If we start a garbage collection on g0 during a
stack split or unsplit, we'll see morestack or lessstack
at the top of the stack. Record an argument frame size
for those, and record that they terminate the stack.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11533043
Deferreturn is synthesizing a new call frame.
It must not be interrupted between copying the args there
and fixing up the program counter, or else the stack will
be in an inconsistent state, one that will confuse the
garbage collector.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11522043
With preemption, _sfloat2 can show up in stack traces.
Write the function prototype in a way that accurately
shows the frame size and the fact that it might contain
pointers.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11523043
Windows was the only one seeing this bug reliably in the builder,
but it was easy to reproduce using 'GOGC=1 go test strconv'.
concatstring looked like it took only one string, but in fact it
takes a long list of strings. Add an explicit ... so that the traceback
will not use the "fixed" frame size and instead look at the
frame size metadata recorded by the caller.
R=golang-dev
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/11531043
Be consistent with os.File, strings.Reader, bytes.Reader, etc,
which all allow seeks past the end.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/11403043
Otherwise the tests in pkg/runtime fail:
runtime: unknown argument frame size for runtime.deferreturn called from 0x48657b [runtime_test.func·022]
fatal error: invalid stack
...
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/11483043
Update #543
I believe the runtime is strong enough now to reenable
preemption during the function prologue.
Assuming this is or can be made stable, it will be in Go 1.2.
More aggressive preemption is not planned for Go 1.2.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/11433045
Currently preemption signal g->stackguard0==StackPreempt
can be lost if it is received when preemption is disabled
(e.g. m->lock!=0). This change duplicates the preemption
signal in g->preempt and restores g->stackguard0
when preemption is enabled.
Update #543.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10792043
With this CL, I believe the runtime always knows
the frame size during the gc walk. There is no fallback
to "assume entire stack frame of caller" anymore.
R=golang-dev, khr, cshapiro, dvyukov
CC=golang-dev
https://golang.org/cl/11374044
Add support for ECDHE-ECDSA (RFC4492), which uses an ephemeral server
key pair to perform ECDH with ECDSA signatures. Like ECDHE-RSA,
ECDHE-ECDSA also provides PFS.
R=agl
CC=golang-dev
https://golang.org/cl/7006047
I have not done the system call stubs in sys_*.s.
I hope to avoid that, because those do not block, so those
frames will not appear in stack traces during garbage
collection.
R=golang-dev, dvyukov, khr
CC=golang-dev
https://golang.org/cl/11360043
While we're here, fix Syscall9 on NetBSD and OpenBSD:
it was storing the results into the wrong memory locations.
I guess no one uses that function's results on those systems.
Part of cleaning up stack traces and argument frame information.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11355044
Design at http://golang.org/s/go12symtab.
This enables some cleanup of the garbage collector metadata
that will be done in future CLs.
This CL does not move the old symtab and pclntab back into
an unmapped section of the file. That's a bit tricky and will be
done separately.
Fixes#4020.
R=golang-dev, dave, cshapiro, iant, r
CC=golang-dev, nigeltao
https://golang.org/cl/11085043
Race instrumentation can allocate, switch stacks, preempt, etc.
All that is not allowed in between fork and exec.
Fixes#4840.
R=golang-dev, daniel.morsing, dave
CC=golang-dev
https://golang.org/cl/11324044
A type switch on a value with map index expressions,
could get a spurious instrumentation from a OTYPESW node.
These nodes do not need instrumentation because after
walk the type switch has been turned into a sequence
of ifs.
Fixes#5890.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/11308043
Sets both the duration from the last data packet to the first
keep alive packet and the duration between keep alive packets to be
the passed duration.
I've tested the function on both Darwin (10.8.4) and 4.2 Linux.
I've compiled (make.bash) for all the OS's and tested (all.bash)
on Darwin and Linux.
R=golang-dev, dave, rsc, dvyukov, presotto+facebook, nick
CC=golang-dev, veyron-team
https://golang.org/cl/11130044
Before:
$ go test -c -cover fmt
$ ./fmt.test -test.covermode=set
PASS
coverage: 65.1% of statements in strconv
$
After:
$ go test -c -cover fmt
$ ./fmt.test
PASS
coverage: 65.1% of statements in strconv
$
In addition to being cumbersome, the old flag didn't make sense:
the cover mode cannot be changed after the binary has been built.
Another useful effect of this CL is that if you happen to do
$ go test -c -covermode=atomic fmt
and then forget you did that and run benchmarks,
the final line of the output (the coverage summary) reminds you
that you are benchmarking with coverage enabled, which might
not be what you want.
$ ./fmt.test -test.bench .
PASS
BenchmarkSprintfEmpty 10000000 217 ns/op
BenchmarkSprintfString 2000000 755 ns/op
BenchmarkSprintfInt 2000000 774 ns/op
BenchmarkSprintfIntInt 1000000 1363 ns/op
BenchmarkSprintfPrefixedInt 1000000 1501 ns/op
BenchmarkSprintfFloat 1000000 1257 ns/op
BenchmarkManyArgs 500000 5346 ns/op
BenchmarkScanInts 1000 2562402 ns/op
BenchmarkScanRecursiveInt 500 3189457 ns/op
coverage: 91.4% of statements
$
As part of passing the new mode setting in via _testmain.go, merge
the two registration mechanisms into one extensible mechanism
(a struct).
R=r
CC=golang-dev
https://golang.org/cl/11219043
I want to think more carefully about this.
We put this in because Marshal encoded named []byte but Unmarshal rejected them.
And we noticed that Marshal's behavior was undocumented so we documented it.
But I am starting to think the docs and Unmarshal were correct and Marshal's
behavior was the problem.
Rolling back to give us more time to think.
««« original CL description
json: unmarshal types that are byte slices.
The json package cheerfully would marshal
type S struct {
IP net.IP
}
but would give an error when unmarshalling. This change allows any
type whose concrete type is a byte slice to be unmarshalled from a
string.
Fixes#5086.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/11161044
»»»
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/11042046
In practice, rejecting an entire structure due to a single invalid byte
in a string is just too picky, and too hard to track down.
Be consistent with the bulk of the standard library by converting
invalid UTF-8 into UTF-8 with replacement runes.
R=golang-dev, crawshaw
CC=golang-dev
https://golang.org/cl/11211045
If the stack frame size is larger than the known-unmapped region at the
bottom of the address space, then the stack split prologue cannot use the usual
condition:
SP - size >= stackguard
because SP - size may wrap around to a very large number.
Instead, if the stack frame is large, the prologue tests:
SP - stackguard >= size
(This ends up being a few instructions more expensive, so we don't do it always.)
Preemption requests register by setting stackguard to a very large value, so
that the first test (SP - size >= stackguard) cannot possibly succeed.
Unfortunately, that same very large value causes a wraparound in the
second test (SP - stackguard >= size), making it succeed incorrectly.
To avoid *that* wraparound, we have to amend the test:
stackguard != StackPreempt && SP - stackguard >= size
This test is only used for functions with large frames, which essentially
always split the stack, so the cost of the few instructions is noise.
This CL and CL 11085043 together fix the known issues with preemption,
at the beginning of a function, so we will be able to try turning it on again.
R=ken2
CC=golang-dev
https://golang.org/cl/11205043
This is a transcript before this change. I've capitalized the text being removed.
Note that it is always near another line that already says fmt, marked with <<<
$ cd $GOROOT/src/pkg/fmt
$ go test -cover
PASS
coverage FOR FMT: 91.3% of statements
ok fmt 0.040s <<<
$ go test -coverpkg strconv
PASS
coverage FOR FMT: 64.9% of statements in strconv
ok fmt 0.039s <<<
$ go test -cover -c
$ ./fmt.test -test.covermode=set <<<
PASS
coverage FOR FMT: 91.3% of statements
$ go test -coverpkg strconv -c
$ ./fmt.test -test.covermode=set <<<
PASS
coverage FOR FMT: 64.9% of statements in strconv
That the summary printed by 'go test [options] fmt' is unchanged:
$ go test -cover fmt
ok fmt 0.040s coverage: 91.3% of statements
$ go test -coverpkg strconv fmt
ok fmt 0.038s coverage: 64.9% of statements in strconv
R=r
CC=gobot, golang-dev
https://golang.org/cl/10932045
The current cas64 definition hard-codes the x86 behavior
of updating *old with the new value when the cas fails.
This is inconsistent with cas32 and casp.
Make it consistent.
This means that the cas64 uses will be epsilon less efficient
than they might be, because they have to do an unnecessary
memory load on x86. But so be it. Code clarity and consistency
is more important.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10909045
The json package cheerfully would marshal
type S struct {
IP net.IP
}
but would give an error when unmarshalling. This change allows any
type whose concrete type is a byte slice to be unmarshalled from a
string.
Fixes#5086.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/11161044
runtime.newproc/ready are deliberately sloppy about waking new M's,
they only ensure that there is at least 1 spinning M.
Currently to compensate for that, schedule() checks if the current P
has local work and there are no spinning M's, it wakes up another one.
It does not work if goroutines do not call schedule.
With this change a spinning M wakes up another M when it finds work to do.
It's also not ideal, but it fixes the underutilization.
A proper check would require to know the exact number of runnable G's,
but it's too expensive to maintain.
Fixes#5586.
This is reincarnation of cl/9776044 with the bug fixed.
The bug was due to code added after cl/9776044 was created:
if(tick - (((uint64)tick*0x4325c53fu)>>36)*61 == 0 && runtime·sched.runqsize > 0) {
runtime·lock(&runtime·sched);
gp = globrunqget(m->p, 1);
runtime·unlock(&runtime·sched);
}
If M gets gp from global runq here, it does not reset m->spinning.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10743044
Currently it crashes as follows:
fatal error: unknown pc
...
goroutine 71698 [runnable]:
runtime.racegoend()
src/pkg/runtime/race.c:171
runtime.goexit()
src/pkg/runtime/proc.c:1276 +0x9
created by runtime_test.testConcurrentReadsAfterGrowth
src/pkg/runtime/map_test.go:264 +0x332
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10674047
Merging a couple of CLs into one, since they collided in my client
and I'm lazy.
1) Fix up output in "go test -cover" case.
We need to tell the testing package the name of the package being tested
and the name of the package being covered. It can then sort out the report.
2) Filter out the _test.go files from coverage processing. We want to measure
what the tests cover, not what's covered in the tests,
The coverage for encoding/gob goes from 82.2% to 88.4%.
There may be a cleaner way to do this - suggestions welcome - but ça suffit.
Fixes#5810.
R=rsc
CC=golang-dev
https://golang.org/cl/10868047
Part 3 of several.
* Linux has grown a SetsockoptByte.
* SetsockoptIPMreqn is handled directly by syscall_linux.go and syscall_freebsd.go.
R=golang-dev, mikioh.mikioh, r, bradfitz
CC=golang-dev
https://golang.org/cl/10775043
The lzw.NewReader doc comment says, "It is the caller's responsibility
to call Close on the ReadCloser when finished reading."
Thanks to Andrew Bonventre for noticing this.
R=r, dsymonds, adg
CC=andybons, golang-dev
https://golang.org/cl/10821043
ReadMIMEHeader is used by net/http, net/mail, and
mime/multipart.
Don't do so many small allocations. Calculate up front
how much we'll probably need.
benchmark old ns/op new ns/op delta
BenchmarkReadMIMEHeader 8433 7467 -11.45%
benchmark old allocs new allocs delta
BenchmarkReadMIMEHeader 23 14 -39.13%
benchmark old bytes new bytes delta
BenchmarkReadMIMEHeader 1705 1343 -21.23%
R=golang-dev, r, iant, adg
CC=golang-dev
https://golang.org/cl/8179043
This does not include AES-GCM yet. Also, it assumes that the handshake and
certificate signature hash are always SHA-256, which is true of the ciphersuites
that we currently support.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10762044
using m->tls[0] to save ucontext pointer is not re-entry safe, and
the old code didn't set it before the early return when signal is
received on non-Go threads.
so misc/cgo/test used to hang when testing issue 5337.
R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/10076045
When deleting a timer, a panic due to nil deref
would leave a lock held, possibly leading to a deadlock
in a defer. Instead return false on a nil timer.
Fixes#5745.
R=golang-dev, daniel.morsing, dvyukov, rsc, iant
CC=golang-dev
https://golang.org/cl/10373047
This CL provides stable in-place sorting by use of
bottom up merge sort with in-place merging done by
the SymMerge algorithm from P.-S. Kim and A. Kutzner.
The additional space needed for stable sorting (in the form of
stack space) is logarithmic in the inputs size n.
Number of calls to Less and Swap grow like O(n * log n) and
O(n * log n * log n):
Stable sorting random data uses significantly more calls
to Swap than the unstable quicksort implementation (5 times more
on n=100, 10 times more on n=1e4 and 23 times more on n=1e8).
The number of calls to Less is practically the same for Sort and
Stable.
Stable sorting 1 million random integers takes 5 times longer
than using Sort.
BenchmarkSortString1K 50000 328662 ns/op
BenchmarkStableString1K 50000 380231 ns/op 1.15 slower
BenchmarkSortInt1K 50000 157336 ns/op
BenchmarkStableInt1K 50000 191167 ns/op 1.22 slower
BenchmarkSortInt64K 1000 14466297 ns/op
BenchmarkStableInt64K 500 16190266 ns/op 1.12 slower
BenchmarkSort1e2 200000 64923 ns/op
BenchmarkStable1e2 50000 167128 ns/op 2.57 slower
BenchmarkSort1e4 1000 14540613 ns/op
BenchmarkStable1e4 100 58117289 ns/op 4.00 slower
BenchmarkSort1e6 5 2429631508 ns/op
BenchmarkStable1e6 1 12077036952 ns/op 4.97 slower
R=golang-dev, bradfitz, iant, 0xjnml, rsc
CC=golang-dev
https://golang.org/cl/9612044
There are various problems, and both Dmitriy and I
will be away for the next week. Make the runtime a bit
more stable while we're gone.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10848043
fn can clearly hold a closure in memory.
argp/pc point into stack and so can hold
in memory a block that was previously
a large stack serment.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/10784043
Depending on net/http means depending on cgo.
When the tree is in a shaky state it's nice to see sync/atomic
pass even if cgo or net causes broken binaries.
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/10753044
After loading a frame of a GIF, check that each pixel
is inside the frame's palette.
Fixes#5401.
R=nigeltao, r
CC=golang-dev
https://golang.org/cl/10597043
On amd64 the frames are very close to the limit for a
nosplit (textflag 7) function, in part because the C compiler
does not make any attempt to reclaim space allocated for
completely registerized variables. Avoid a few short-lived
variables to reclaim two words.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10758043
Currently it replaces GOGCTRACE env var (GODEBUG=gctrace=1).
The plan is to extend it with other type of debug tracing,
e.g. GODEBUG=gctrace=1,schedtrace=100.
R=rsc
CC=bradfitz, daniel.morsing, gobot, golang-dev
https://golang.org/cl/10026045
The last patch for preemptive scheduler,
with this change stoptheworld issues preemption
requests every 100us.
Update #543.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/10264044
On x86 it is a few words lower on the stack than m->morebuf.sp
so it is a more precise check. Enabling the check requires recording
a valid gp->sched in reflect.call too. This is a good thing in general,
since it will make stack traces during reflect.call work better, and it
may be useful for preemption too.
R=dvyukov
CC=golang-dev
https://golang.org/cl/10709043
runtime.entersyscall() sets g->status = Gsyscall,
then calls runtime.lock() which causes stack split.
runtime.newstack() resets g->status to Grunning.
This will lead to crash during GC (world is not stopped) or GC will scan stack incorrectly.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10696043
Also use 2048-bit RSA keys as default in generate_cert.go,
as recommended by the NIST.
R=golang-dev, rsc, bradfitz
CC=golang-dev
https://golang.org/cl/10676043
On my 64-bit machine, despite being 32-bit code, fixed-base
multiplications are 7.1x faster and arbitary multiplications are 2.6x
faster.
It is difficult to review this change. However, the code is essentially
the same as code that has been open-sourced in Chromium. There it has
been successfully performing P-256 operations for several months on
many machines so the arithmetic of the code should be sound.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10551044
Failure on bot:
http://build.golang.org/log/f4c648906e1289ec2237c1d0880fb1a8b1852a08
««« original CL description
runtime: fix CPU underutilization
runtime.newproc/ready are deliberately sloppy about waking new M's,
they only ensure that there is at least 1 spinning M.
Currently to compensate for that, schedule() checks if the current P
has local work and there are no spinning M's, it wakes up another one.
It does not work if goroutines do not call schedule.
With this change a spinning M wakes up another M when it finds work to do.
It's also not ideal, but it fixes the underutilization.
A proper check would require to know the exact number of runnable G's,
but it's too expensive to maintain.
Fixes#5586.
R=rsc
TBR=rsc
CC=gobot, golang-dev
https://golang.org/cl/9776044
»»»
R=golang-dev
CC=golang-dev
https://golang.org/cl/10692043
runtime.newproc/ready are deliberately sloppy about waking new M's,
they only ensure that there is at least 1 spinning M.
Currently to compensate for that, schedule() checks if the current P
has local work and there are no spinning M's, it wakes up another one.
It does not work if goroutines do not call schedule.
With this change a spinning M wakes up another M when it finds work to do.
It's also not ideal, but it fixes the underutilization.
A proper check would require to know the exact number of runnable G's,
but it's too expensive to maintain.
Fixes#5586.
R=rsc
CC=gobot, golang-dev
https://golang.org/cl/9776044
Current code can print more arguments than necessary
and also incorrectly prints "...".
Update #5723.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10689043
Until now, the goroutine state has been scattered during the
execution of newstack and oldstack. It's all there, and those routines
know how to get back to a working goroutine, but other pieces of
the system, like stack traces, do not. If something does interrupt
the newstack or oldstack execution, the rest of the system can't
understand the goroutine. For example, if newstack decides there
is an overflow and calls throw, the stack tracer wouldn't dump the
goroutine correctly.
For newstack to save a useful state snapshot, it needs to be able
to rewind the PC in the function that triggered the split back to
the beginning of the function. (The PC is a few instructions in, just
after the call to morestack.) To make that possible, we change the
prologues to insert a jmp back to the beginning of the function
after the call to morestack. That is, the prologue used to be roughly:
TEXT myfunc
check for split
jmpcond nosplit
call morestack
nosplit:
sub $xxx, sp
Now an extra instruction is inserted after the call:
TEXT myfunc
start:
check for split
jmpcond nosplit
call morestack
jmp start
nosplit:
sub $xxx, sp
The jmp is not executed directly. It is decoded and simulated by
runtime.rewindmorestack to discover the beginning of the function,
and then the call to morestack returns directly to the start label
instead of to the jump instruction. So logically the jmp is still
executed, just not by the cpu.
The prologue thus repeats in the case of a function that needs a
stack split, but against the cost of the split itself, the extra few
instructions are noise. The repeated prologue has the nice effect of
making a stack split double-check that the new stack is big enough:
if morestack happens to return on a too-small stack, we'll now notice
before corruption happens.
The ability for newstack to rewind to the beginning of the function
should help preemption too. If newstack decides that it was called
for preemption instead of a stack split, it now has the goroutine state
correctly paused if rescheduling is needed, and when the goroutine
can run again, it can return to the start label on its original stack
and re-execute the split check.
Here is an example of a split stack overflow showing the full
trace, without any special cases in the stack printer.
(This one was triggered by making the split check incorrect.)
runtime: newstack framesize=0x0 argsize=0x18 sp=0x6aebd0 stack=[0x6b0000, 0x6b0fa0]
morebuf={pc:0x69f5b sp:0x6aebd8 lr:0x0}
sched={pc:0x68880 sp:0x6aebd0 lr:0x0 ctxt:0x34e700}
runtime: split stack overflow: 0x6aebd0 < 0x6b0000
fatal error: runtime: split stack overflow
goroutine 1 [stack split]:
runtime.mallocgc(0x290, 0x100000000, 0x1)
/Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:21 fp=0x6aebd8
runtime.new()
/Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:682 +0x5b fp=0x6aec08
go/build.(*Context).Import(0x5ae340, 0xc210030c71, 0xa, 0xc2100b4380, 0x1b, ...)
/Users/rsc/g/go/src/pkg/go/build/build.go:424 +0x3a fp=0x6b00a0
main.loadImport(0xc210030c71, 0xa, 0xc2100b4380, 0x1b, 0xc2100b42c0, ...)
/Users/rsc/g/go/src/cmd/go/pkg.go:249 +0x371 fp=0x6b01a8
main.(*Package).load(0xc21017c800, 0xc2100b42c0, 0xc2101828c0, 0x0, 0x0, ...)
/Users/rsc/g/go/src/cmd/go/pkg.go:431 +0x2801 fp=0x6b0c98
main.loadPackage(0x369040, 0x7, 0xc2100b42c0, 0x0)
/Users/rsc/g/go/src/cmd/go/pkg.go:709 +0x857 fp=0x6b0f80
----- stack segment boundary -----
main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc2100e6c00, 0xc2100e5750, ...)
/Users/rsc/g/go/src/cmd/go/build.go:539 +0x437 fp=0x6b14a0
main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc21015b400, 0x2, ...)
/Users/rsc/g/go/src/cmd/go/build.go:528 +0x1d2 fp=0x6b1658
main.(*builder).test(0xc2100902a0, 0xc210092000, 0x0, 0x0, 0xc21008ff60, ...)
/Users/rsc/g/go/src/cmd/go/test.go:622 +0x1b53 fp=0x6b1f68
----- stack segment boundary -----
main.runTest(0x5a6b20, 0xc21000a020, 0x2, 0x2)
/Users/rsc/g/go/src/cmd/go/test.go:366 +0xd09 fp=0x6a5cf0
main.main()
/Users/rsc/g/go/src/cmd/go/main.go:161 +0x4f9 fp=0x6a5f78
runtime.main()
/Users/rsc/g/go/src/pkg/runtime/proc.c:183 +0x92 fp=0x6a5fa0
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1266 fp=0x6a5fa8
And here is a seg fault during oldstack:
SIGSEGV: segmentation violation
PC=0x1b2a6
runtime.oldstack()
/Users/rsc/g/go/src/pkg/runtime/stack.c:159 +0x76
runtime.lessstack()
/Users/rsc/g/go/src/pkg/runtime/asm_amd64.s:270 +0x22
goroutine 1 [stack unsplit]:
fmt.(*pp).printArg(0x2102e64e0, 0xe5c80, 0x2102c9220, 0x73, 0x0, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:818 +0x3d3 fp=0x221031e6f8
fmt.(*pp).doPrintf(0x2102e64e0, 0x12fb20, 0x2, 0x221031eb98, 0x1, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:1183 +0x15cb fp=0x221031eaf0
fmt.Sprintf(0x12fb20, 0x2, 0x221031eb98, 0x1, 0x1, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:234 +0x67 fp=0x221031eb40
flag.(*stringValue).String(0x2102c9210, 0x1, 0x0)
/Users/rsc/g/go/src/pkg/flag/flag.go:180 +0xb3 fp=0x221031ebb0
flag.(*FlagSet).Var(0x2102f6000, 0x293d38, 0x2102c9210, 0x143490, 0xa, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:633 +0x40 fp=0x221031eca0
flag.(*FlagSet).StringVar(0x2102f6000, 0x2102c9210, 0x143490, 0xa, 0x12fa60, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:550 +0x91 fp=0x221031ece8
flag.(*FlagSet).String(0x2102f6000, 0x143490, 0xa, 0x12fa60, 0x0, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:563 +0x87 fp=0x221031ed38
flag.String(0x143490, 0xa, 0x12fa60, 0x0, 0x161950, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:570 +0x6b fp=0x221031ed80
testing.init()
/Users/rsc/g/go/src/pkg/testing/testing.go:-531 +0xbb fp=0x221031edc0
strings_test.init()
/Users/rsc/g/go/src/pkg/strings/strings_test.go:1115 +0x62 fp=0x221031ef70
main.init()
strings/_test/_testmain.go:90 +0x3d fp=0x221031ef78
runtime.main()
/Users/rsc/g/go/src/pkg/runtime/proc.c:180 +0x8a fp=0x221031efa0
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1269 fp=0x221031efa8
goroutine 2 [runnable]:
runtime.MHeap_Scavenger()
/Users/rsc/g/go/src/pkg/runtime/mheap.c:438
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1269
created by runtime.main
/Users/rsc/g/go/src/pkg/runtime/proc.c:166
rax 0x23ccc0
rbx 0x23ccc0
rcx 0x0
rdx 0x38
rdi 0x2102c0170
rsi 0x221032cfe0
rbp 0x221032cfa0
rsp 0x7fff5fbff5b0
r8 0x2102c0120
r9 0x221032cfa0
r10 0x221032c000
r11 0x104ce8
r12 0xe5c80
r13 0x1be82baac718
r14 0x13091135f7d69200
r15 0x0
rip 0x1b2a6
rflags 0x10246
cs 0x2b
fs 0x0
gs 0x0
Fixes#5723.
R=r, dvyukov, go.peter.90, dave, iant
CC=golang-dev
https://golang.org/cl/10360048
Setenv("AN_ENV_VAR", "") deletes AN_ENV_VAR instead of setting it
to "" at this moment. Also Getenv("AN_ENV_VAR") returns "not found",
if AN_ENV_VAR is "". Change it, so they behave like unix.
Fixes#5610
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10594043
Makes it easy to ask the simple question, what is the hash of this data?
Also fix the commentary and prints in Sum256.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10630043
Makes it easy to ask the simple question, what is the hash of this data?
Also mark block as non-escaping.
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10624044
Currently more than 1 gorutine can execute raceWrite() in Wait()
in the following scenario:
1. goroutine 1 executes first check of wg.counter, sees that it's == 0
2. goroutine 2 executes first check of wg.counter, sees that it's == 0
3. goroutine 2 locks the mutex, sees that he is the first waiter and executes raceWrite()
4. goroutine 2 block on the semaphore
5. goroutine 3 executes Done() and unblocks goroutine 2
6. goroutine 1 lock the mutex, sees that he is the first waiter and executes raceWrite()
It produces the following false report:
WARNING: DATA RACE
Write by goroutine 35:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.TestNoRaceWaitGroupMultipleWait2()
src/pkg/runtime/race/testdata/waitgroup_test.go:156 +0x19a
testing.tRunner()
src/pkg/testing/testing.go:361 +0x108
Previous write by goroutine 36:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.func·012()
src/pkg/runtime/race/testdata/waitgroup_test.go:148 +0x4d
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10424043
Resubmit 3c2cddfbdaec now that windows callbacks
are not generated during runtime.
Fixes#5494
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/10487043
- change runtime_pollWait so it does not return
closed or timeout if IO is ready - windows must
know if IO has completed or not even after
interruption;
- add (*pollDesc).Prepare(mode int) that can be
used for both read and write, same for Wait;
- introduce runtime_pollWaitCanceled and expose
it in net as (*pollDesc).WaitCanceled(mode int);
Full windows netpoll changes are
here https://golang.org/cl/8670044/.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/10485043
The compiler still gets the escape analysis wrong, but the annotation here is correct.
R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/10514046
No semantic change.
I found the wording distracting in a couple of instances and was moved to improve it.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10478048
If a server response contains a Content-Length and the body is short,
the Transport should end in io.ErrUnexpectedEOF, not io.EOF.
Fixes#5738
R=golang-dev, kevlar, r
CC=golang-dev
https://golang.org/cl/10237050
until we decide what to do with issues 5659/5736.
Profiling with race detector is not very useful in general,
and now it makes race builders red.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10523043
Time is a tiny struct, so the compiler copies a Time by
copying each of the three fields.
The layout of a time on amd64 is [ptr int32 gap32 ptr].
Copying a Time onto a location that formerly held a pointer in the
second word changes only the low 32 bits, creating a different
but still plausible pointer. This confuses the garbage collector
when it appears in argument or result frames.
To avoid this problem, declare nsec as uintptr, so that there is
no gap on amd64 anymore, and therefore no partial pointers.
Note that rearranging the fields to put the int32 last still leaves
a gap - [ptr ptr int32 gap32] - because Time must have a total
size that is ptr-width aligned.
Update #5749
This CL is enough to fix the problem, but we should still do
the other actions listed in the initial report. We're not too far
from completely precise collection.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/10504043
The tradition is to use _posix when the platform extends beyond unix variants. As windows has its own file, rename to the more usual _unix.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10320043
If time.Sub results in a value that won't fit in a Duration (int64),
return either the min or max int64 value as appropriate.
Fixes#5011.
R=golang-dev, bradfitz, r, rsc
CC=golang-dev
https://golang.org/cl/10328043
trivial: it is not a serious problem to leak a fd in a short lived process, but it was obscuring my investigation of issue 5593.
R=golang-dev, iant, bradfitz
CC=golang-dev
https://golang.org/cl/10391043
The old code worked, somewhat on accident, but was confusing,
and had a useless assignment to the inner err. It worked
because url.Parse parses just about anything, so the outer err
was always nil, so it always fell through to the bottom return
statement, even without the "err = nil" line.
Instead, just have two return statements, and add a comment.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10448044
TLS clients send ciphersuites in preference order (most prefereable
first). This change alters the order so that ECDHE comes before plain
RSA, and RC4 comes before AES (because of the Lucky13 attack).
This is unlikely to have much effect: as a server, the code uses the
client's ciphersuite order by default and, as a client, the non-Go
server probably imposes its order.
R=golang-dev, r, raggi, jsing
CC=golang-dev
https://golang.org/cl/10372045
The single flag -cover provides the default simplest behavior.
The other flags, -covermode and -coverprofile, provide more
control. The three flags interconnect to work well.
R=rsc, adg
CC=golang-dev
https://golang.org/cl/10364044
Move the data dumper to the testing package, where it has access
to file I/O.
Print a percentage value at the end of the run.
R=rsc, adg
CC=golang-dev
https://golang.org/cl/10264045
use correct field count when resolving nameservers via /net/dns on Plan 9.
we incorrectly check for 4 fields instead of 3 when parsing the result of /net/dns, and get no results
R=golang-dev, ality
CC=golang-dev
https://golang.org/cl/10182044
Don't panic when the underlying Writer isn't a Closer. And
document what Close does and clarify that it's not a Flush.
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10310043
If first GC runs concurrently with setGCPercent,
it can overwrite gcpercent value with default.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/10242047
Currently global runqueue is starved if a group of goroutines
constantly respawn each other (local runqueue never becomes empty).
Fixes#5639.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/10042044
It was used to request large stack segment for GC
when it was running not on g0.
Now GC is running on g0 with large stack,
and it is not needed anymore.
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/10242045
No need to change to Grunnable state.
Add some more checks for Grunning state.
R=golang-dev, rsc, khr, dvyukov
CC=golang-dev
https://golang.org/cl/10186045
In Issue 5625, Russ says: "We should at least have a cache of
inflight lookups, so that 100 simultaneous dials of one host
name don't do the work 100x. That's easy and (assume we forget
the answer once they all get it) doesn't pose any consistency
problems. It just merges simultaneous work."
This brings in singleflight (unexported) from Google /
Camlistore, but without its tests. Maybe we should put it
somewhere in the standard library. But not now.
Update #5625
R=golang-dev, iant, cespare, rsc, dave, rogpeppe, remyoudompheng
CC=golang-dev
https://golang.org/cl/10079043
The previous implementation would only record access to
the address of the array but the memory access to the whole
memory range must be recorded instead.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/8053044
These are required to correctly determine the End() of the node.
Also set these fields in go/parser and use them in go/printer.
This is a backward-compatible API change.
R=gri, r
CC=golang-dev
https://golang.org/cl/10189043
Instrumentation of ntest expression should go to ntest->init.
Same for nincr.
Fixes#5340.
R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/10026046
Obscure misfeature now fixed: When run from "go test", profiles were always
written in the package's source directory. This change puts them in the directory
where "go test" is run.
Also fix a couple of problems causing errors in testing.after to go unreported
unless -v was set.
R=rsc, minux.ma, iant, alex.brainman
CC=golang-dev
https://golang.org/cl/10234044
Add gostartcall and gostartcallfn.
The old gogocall = gostartcall + gogo.
The old gogocallfn = gostartcallfn + gogo.
R=dvyukov, minux.ma
CC=golang-dev
https://golang.org/cl/10036044
In starttheworld() we assume that P's with local work
are situated in the beginning of idle P list.
However, once we start the first M, it can execute all local G's
and steal G's from other P's.
That breaks the assumption above. Thus starttheworld() will fail
to start some P's with local work.
It seems that it can not lead to very bad things, but still
it's wrong and breaks other assumtions
(e.g. we can have a spinning M with local work).
The fix is to collect all P's with local work first,
and only then start them.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10051045
The garbage collection routine addframeroots is duplicating
logic in the traceback routine that calls it, sometimes correctly,
sometimes incorrectly, sometimes incompletely.
Pass necessary information to addframeroots instead of
deriving it anew.
Should make addframeroots significantly more robust.
It's certainly smaller.
Also try to standardize on uintptr for saved pc, sp values.
Will make CL 10036044 trivial.
R=golang-dev, dave, dvyukov
CC=golang-dev
https://golang.org/cl/10169045
There's no reason to use a different name on each architecture,
and doing so makes it impossible for portable code to refer to
the original Go runtime entry point. Rename it _rt0_go everywhere.
This is a global search and replace only.
R=golang-dev, bradfitz, minux.ma
CC=golang-dev
https://golang.org/cl/10196043
The first identifier in an Object Identifer must be between 0 and 2
inclusive. The range of values that the second one can take depends
on the value of the first one.
The two first identifiers are not necessarily encoded in a single octet,
but in a varint.
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10140046
Do not synchronize Add(1) with Wait().
Imitate read on first Add(1) and write on Wait(),
it allows to catch common misuses of WaitGroup:
- Add() called in the additional goroutine itself
- incorrect reuse of WaitGroup with multiple waiters
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/10093044
Also reduce FixAlloc allocation granulatiry from 128k to 16k,
small programs do not need that much memory for MCache's and MSpan's.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/10140044
Especially important for Windows because it reserves VM
only in multiple of 64k.
R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/10082048
Count only number of frees, everything else is derivable
and does not need to be counted on every malloc.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 68 66 -3.07%
BenchmarkMalloc16 75 70 -6.48%
BenchmarkMallocTypeInfo8 102 97 -4.80%
BenchmarkMallocTypeInfo16 108 105 -2.78%
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/9776043
CFLAGS comes before CPPFLAGS.
Also fix one typo CPPCFLAGS.
Cleanup for CL 8248043.
R=golang-dev, iant, alberto.garcia.hierro
CC=golang-dev
https://golang.org/cl/9965045
The significant change between TLS 1.0 and 1.1 is the addition of an explicit IV in the case of CBC encrypted records. Support for TLS 1.1 is needed in order to support TLS 1.2.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7880043
Remove unnecessary ( ) around == in && clause.
Add { } around multiline if body, even though it's one statement.
Add runtime: prefix to printed errors.
R=cshapiro, iant
CC=golang-dev
https://golang.org/cl/9685047
This is part of preemptive scheduler.
stackguard0 is checked in split stack checks and can be set to StackPreempt.
stackguard is not set to StackPreempt (holds the original value).
R=golang-dev, daniel.morsing, iant
CC=golang-dev
https://golang.org/cl/9875043
Fixes#5599.
Thanks to minux.ma for the suggested fix.
As we now have a harness to test testing internal functions I added some coverage for testing.roundUp, as it is the main consumer of roundDown10.
R=minux.ma, kr, r
CC=golang-dev
https://golang.org/cl/9926043
Before this change, grow work was done only
during map writes to ensure multithreaded safety.
This can lead to maps remaining in a partially
grown state for a long time, potentially forever.
This change allows grow work to happen during reads,
which will lead to grow work finishing sooner, making
the resulting map smaller and faster.
Grow work is not done in parallel. Reads can
happen in parallel while grow work is happening.
R=golang-dev, dvyukov, khr, iant
CC=golang-dev
https://golang.org/cl/8852047
instead of regular g stack. We do this so that the g stack
we're currently running on is no longer changing. Cuts
the root set down a bit (g0 stacks are not scanned, and
we don't need to scan gc's internal state). Also an
enabler for copyable stacks.
R=golang-dev, cshapiro, khr, 0xe2.0x9a.0x9b, dvyukov, rsc, iant
CC=golang-dev
https://golang.org/cl/9754044
* Add a CXXFiles field to Package, which includes .cc, .cpp and .cxx files.
* CXXFiles are compiled using g++, which can be overridden using the CXX environment variable.
* Include .hh, .hpp and .hxx files in HFiles.
* Add support for CPPFLAGS (used for both C and C++) and CXXFLAGS (used only for C++) in cgo directive.
* Changed pkg-config cgo directive to modify CPPFLAGS rather than CFLAGS, so both C and C++ files get any flag returned by pkg-config --cflags.
Fixes#1476.
R=iant, r
CC=bradfitz, gobot, golang-dev, iant, minux.ma, remyoudompheng, seb.binet
https://golang.org/cl/8248043
mheap.map become a pointer, so nelem(h->map) returns 1 rather than the map size.
As the result coalescing with subsequent spans does not happen.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/9649046
It is a caching wrapper around SysAlloc() that can allocate small chunks.
Use it for symtab allocations. Reduces number of symtab walks from 4 to 3
(reduces buildfuncs time from 10ms to 7.5ms on a large binary,
reduces initial heap size by 680K on the same binary).
Also can be used for type info allocation, itab allocation.
There are also several places in GC where we do the same thing,
they can be changed to use persistentalloc().
Also can be used in FixAlloc, because each instance of FixAlloc allocates
in 128K regions, which is too eager.
Reincarnation of committed and rolled back https://golang.org/cl/9805043
The latent bugs that it revealed are fixed:
https://golang.org/cl/9837049https://golang.org/cl/9778048
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/9778049
Then use the limit to make sure MHeap_LookupMaybe & inlined
copies don't return a span if the pointer is beyond the limit.
Use this fact to optimize all call sites.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/9869045
As the code now says:
We are forced to return a float64 because the API is silly, but do
the division as integers so we can ask if AllocsPerRun()==1
instead of AllocsPerRun()<2.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/9837049
A nosplits was assumed to have no argument information and no
pointer map. However, nosplits created by the linker often
have both. This change uses the pointer map size as an
alternate source of argument size when processing a nosplit.
In addition, the symbol table construction pointer map size
and argument size consistency check is strengthened. If a
nptrs is greater than 0 it must be equal to the number of
argument words.
R=golang-dev, khr, khr
CC=golang-dev
https://golang.org/cl/9666047
to avoid unintentionally clobber R9/R10.
Thanks Lucio for the suggestion.
PS: yes, this could be considered a big change (but not an API change), but
as it turns out even temporarily changes R9/R10 in user code is unsafe and
leads to very hard to diagnose problems later, better to disable using R9/R10
when the user first uses it.
See CL 6300043 and CL 6305100 for two problems caused by misusing R9/R10.
R=golang-dev, khr, rsc
CC=golang-dev
https://golang.org/cl/9840043
The old code put the index before the period in the precision;
it should be after so it's always before the star, as documented.
A little trickier to do in one pass but compensated for by more
tests and catching a couple of other error cases.
R=rsc
CC=golang-dev
https://golang.org/cl/9751044
Currently we only check the leaf node's issuer against the list of
distinguished names in the server's CertificateRequest message. This
will fail if the client certiciate has more than one certificate in
the path and the leaf node issuer isn't in the list of distinguished
names, but the issuer's issuer was in the distinguished names.
R=agl, agl
CC=gobot, golang-dev
https://golang.org/cl/9795043
This is needed for preemptive scheduler, because during
stoptheworld we want to wait with timeout and re-preempt
M's on timeout.
R=golang-dev, remyoudompheng, iant
CC=golang-dev
https://golang.org/cl/9375043
With this change the compiler emits a bitmap for each function
covering its stack frame arguments area. If an argument word
is known to contain a pointer, a bit is set. The garbage
collector reads this information when scanning the stack by
frames and uses it to ignores locations known to not contain a
pointer.
R=golang-dev, bradfitz, daniel.morsing, dvyukov, khr, khr, iant, cshapiro
CC=golang-dev
https://golang.org/cl/9223046
This depends on: 9791044: runtime: allocate page table lazily
Once page table is moved out of heap, the heap becomes small.
This removes unnecessary dereferences during heap access.
No logical changes.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/9802043
This removes the 256MB memory allocation at startup,
which conflicts with ulimit.
Also will allow to eliminate an unnecessary memory dereference in GC,
because the page table is usually mapped at known address.
Update #5049.
Update #5236.
R=golang-dev, khr, r, khr, rsc
CC=golang-dev
https://golang.org/cl/9791044
Currently the test closes random files descriptors,
which leads to hang (in particular if netpoll fd is closed).
Try to open only fd 3, since the parent process expects it to be fd 3 anyway.
Fixes#5571.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9778048
The 'n' variable is used during rescan initiation in GC_END case,
but it's overwritten with chan capacity in GC_CHAN case.
As the result rescan is done with the wrong object size.
Fixes#5554.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/9831043
multiple failures on amd64
««« original CL description
runtime: introduce helper persistentalloc() function
It is a caching wrapper around SysAlloc() that can allocate small chunks.
Use it for symtab allocations. Reduces number of symtab walks from 4 to 3
(reduces buildfuncs time from 10ms to 7.5ms on a large binary,
reduces initial heap size by 680K on the same binary).
Also can be used for type info allocation, itab allocation.
There are also several places in GC where we do the same thing,
they can be changed to use persistentalloc().
Also can be used in FixAlloc, because each instance of FixAlloc allocates
in 128K regions, which is too eager.
R=golang-dev, daniel.morsing, khr
CC=golang-dev
https://golang.org/cl/9805043
»»»
R=golang-dev
CC=golang-dev
https://golang.org/cl/9822043
It is a caching wrapper around SysAlloc() that can allocate small chunks.
Use it for symtab allocations. Reduces number of symtab walks from 4 to 3
(reduces buildfuncs time from 10ms to 7.5ms on a large binary,
reduces initial heap size by 680K on the same binary).
Also can be used for type info allocation, itab allocation.
There are also several places in GC where we do the same thing,
they can be changed to use persistentalloc().
Also can be used in FixAlloc, because each instance of FixAlloc allocates
in 128K regions, which is too eager.
R=golang-dev, daniel.morsing, khr
CC=golang-dev
https://golang.org/cl/9805043
Variables in data sections of 32-bit executables interfere with
garbage collector's ability to free objects and/or unnecessarily
slow down the garbage collector.
This changeset moves some static variables to .noptr sections.
'files' in symtab.c is now allocated dynamically.
R=golang-dev, dvyukov, minux.ma
CC=golang-dev
https://golang.org/cl/9786044
This text is added to doc.go:
Explicit argument indexes:
In Printf, Sprintf, and Fprintf, the default behavior is for each
formatting verb to format successive arguments passed in the call.
However, the notation [n] immediately before the verb indicates that the
nth one-indexed argument is to be formatted instead. The same notation
before a '*' for a width or precision selects the argument index holding
the value. After processing a bracketed expression [n], arguments n+1,
n+2, etc. will be processed unless otherwise directed.
For example,
fmt.Sprintf("%[2]d %[1]d\n", 11, 22)
will yield "22, 11", while
fmt.Sprintf("%[3]*[2].*[1]f", 12.0, 2, 6),
equivalent to
fmt.Sprintf("%6.2f", 12.0),
will yield " 12.00". Because an explicit index affects subsequent verbs,
this notation can be used to print the same values multiple times
by resetting the index for the first argument to be repeated:
fmt.Sprintf("%d %d %#[1]x %#x", 16, 17)
will yield "16 17 0x10 0x11".
The notation chosen differs from that in C, but I believe it's easier to read
and to remember (we're indexing the arguments), and compatibility with
C's printf was never a strong goal anyway.
While we're here, change the word "field" to "arg" or "argument" in the
code; it was being misused and was confusing.
R=rsc, bradfitz, rogpeppe, minux.ma, peter.armitage
CC=golang-dev
https://golang.org/cl/9680043
crypto/x509 has ended up with a variety of error formats. This change makes them all start with "x509: ".
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9736043
According to X.690, only 0 and 255 are allowed as values
for encoded booleans. Also added some test for parsing
booleans
R=golang-dev, agl, r
CC=golang-dev
https://golang.org/cl/9692043
The problem was that server handlers block on done<-,
the goroutine that reads from done blocks on count<-,
and the main goroutine that is supposed to read from count
waits for server handlers to exit.
Fixes#5547.
R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/9722043
This only affects calls where both ReaderFrom and WriterTo are implemented. WriterTo can issue one large write, while ReaderFrom must Read until EOF, potentially reallocating when out of memory. With one large Write, the Writer only needs to allocate once.
This also helps in ioutil.Discard since we can avoid copying memory when the Reader implements WriterTo.
R=golang-dev, dsymonds, remyoudompheng, bradfitz
CC=golang-dev, minux.ma
https://golang.org/cl/9462044
This change contains an implementation of the RSASSA-PSS signature
algorithm described in RFC 3447.
R=agl, agl
CC=gobot, golang-dev, r
https://golang.org/cl/9438043
This CL adds missing IPv6 socket options which are required
to control IPv6 as described in RFC 3493, RFC 3542.
Update #5538
R=golang-dev, dave, iant
CC=golang-dev
https://golang.org/cl/9373046
1) go/doc:
- create correct ast.FuncType
- use more commonly used variable names in a test case
2) make ast.FuncType.Pos robust in case of incorrect ASTs
R=golang-dev
CC=golang-dev
https://golang.org/cl/9651044
This is needed for preemptive scheduler, because the goroutine
can be preempted at surprising points.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/9376043
When cgo is used, runtime creates an additional M to handle callbacks on threads not created by Go.
This effectively disabled deadlock detection, which is a right thing, because Go program can be blocked
and only serve callbacks on external threads.
This also disables deadlock detection under race detector, because it happens to use cgo.
With this change the additional M is created lazily on first cgo call. So deadlock detector
works for programs that import "C", "net" or "net/http/pprof" but do not use them in fact.
Also fixes deadlock detector under race detector.
It should be fine to create the M later, because C code can not call into Go before first cgo call,
because C code does not know when Go initialization has completed. So a Go program need to call into C
first either to create an external thread, or notify a thread created in global ctor that Go
initialization has completed.
Fixes#4973.
Fixes#5475.
R=golang-dev, minux.ma, iant
CC=golang-dev
https://golang.org/cl/9303046
The original code was correct. The count returned must be the length
of the input slice, not the length of the formatted message.
««« original CL description
log/syslog: report errors from Fprintf
Thanks to chiparus for identifying this.
Fixes#5541.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/9658043
»»»
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/9644044
Currently per-sizeclass stats are lost for destroyed MCache's. This patch fixes this.
Also, only update mstats.heap_alloc on heap operations, because that's the only
stat that needs to be promptly updated. Everything else needs to be up-to-date only in ReadMemStats().
R=golang-dev, remyoudompheng, dave, iant
CC=golang-dev
https://golang.org/cl/9207047
The nlistmin/size thresholds are copied from tcmalloc,
but are unnecesary for Go malloc. We do not do explicit
frees into MCache. For sparse cases when we do (mainly hashmap),
simpler logic will do.
R=rsc, dave, iant
CC=gobot, golang-dev, r, remyoudompheng
https://golang.org/cl/9373043
A bufio.Writer.Flush marks the usual end of a Writer's
life. Recycle its internal buffer on those explicit flushes,
but not on normal, as-needed internal flushes.
benchmark old ns/op new ns/op delta
BenchmarkWriterEmpty 1959 727 -62.89%
benchmark old allocs new allocs delta
BenchmarkWriterEmpty 2 1 -50.00%
benchmark old bytes new bytes delta
BenchmarkWriterEmpty 4215 83 -98.03%
R=gri, iant
CC=gobot, golang-dev, voidlogic7
https://golang.org/cl/9459044
This should have been removed in 45c12efb4635. Not a correctness
issue, but unnecessary work.
This CL also adds paranoia checks in removeDep so this doesn't
happen again.
Fixes#5502
R=adg
CC=gobot, golang-dev, google
https://golang.org/cl/9543043
undo CL 8478044 / 0d28fd55e721
Lack of consensus.
««« original CL description
time: add Time.FormatAppend
This is a version of Time.Format that doesn't require allocation.
Fixes#5192
Update #5195
R=r
CC=gobot, golang-dev
https://golang.org/cl/8478044
»»»
R=r
CC=golang-dev
https://golang.org/cl/9462049
This isn't clearly a bug on Go's part, but it triggers a bug in Firefox
which means that crypto/tls and net/http cannot be wired up together
unless NextProtos includes "http/1.1". When net/http sets up the
tls.Config, it does this and so works fine. But anyone setting up the
tls.Config themselves will hit the Firefox bug.
Fixes#5445.
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/9539045
Several places used io.WriteString unnecessarily when the
static type already implemented WriteString. No need to
check for it at runtime.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9608043
It contains the LHS of the range clause and gets
instrumented by racewalk, but it doesn't have any meaning.
Fixes#5446.
R=golang-dev, dvyukov, daniel.morsing, r
CC=golang-dev
https://golang.org/cl/9560044
Failures caused by errors like invalid signatures or missing hash
functions cause rather generic, unhelpful error messages because no
trust chain can be constructed: "x509: certificate signed by unknown
authority."
With this change, authority errors may contain the reason why an
arbitary candidate step in the chain was rejected. For example, in the
event of a missing hash function the error looks like:
x509: certificate signed by unknown authority (possibly because of
"crypto/x509: cannot verify signature: algorithm unimplemented" while
trying to verify candidate authority certificate 'Thawte SGC CA')
Fixes 5058.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9104051
Share garbage between different bufio Readers. When a Reader
has zero buffered data, put its buffer into a pool.
This acknowledges that most bufio.Readers eventually get
read to completion, and their buffers are then no longer
needed.
benchmark old ns/op new ns/op delta
BenchmarkReaderEmpty 2993 1058 -64.65%
benchmark old allocs new allocs delta
BenchmarkReaderEmpty 3 2 -33.33%
benchmark old bytes new bytes delta
BenchmarkReaderEmpty 4278 133 -96.89%
Update #5100
R=r
CC=adg, dvyukov, gobot, golang-dev, rogpeppe
https://golang.org/cl/8819049
The stack scanner for not started goroutines ignored the arguments
area when its size was unknown. With this change, the distance
between the stack pointer and the stack base will be used instead.
Fixes#5486
R=golang-dev, bradfitz, iant, dvyukov
CC=golang-dev
https://golang.org/cl/9440043
A test added in b37d2fdcc4d9 didn't work with some values of GOMAXPROCS
because the defer statements were in the wrong order: the Pipe could be
closed before the TLS Client was.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/9187047
If a slice points to an array embedded in a struct,
the whole struct can be incorrectly scanned as the slice buffer.
Fixes#5443.
R=cshapiro, iant, r, cshapiro, minux.ma
CC=bradfitz, gobot, golang-dev
https://golang.org/cl/9372044
Allocs of size 16 can bypass atomic set of the allocated bit, while allocs of size 8 can not.
Allocs with and w/o type info hit different paths inside of malloc.
Current results on linux/amd64:
BenchmarkMalloc8 50000000 43.6 ns/op
BenchmarkMalloc16 50000000 46.7 ns/op
BenchmarkMallocTypeInfo8 50000000 61.3 ns/op
BenchmarkMallocTypeInfo16 50000000 63.5 ns/op
R=golang-dev, remyoudompheng, minux.ma, bradfitz, iant
CC=golang-dev
https://golang.org/cl/9090045
for checking for page boundary. Also avoid boundary check
when >=16 bytes are hashed.
benchmark old ns/op new ns/op delta
BenchmarkHashStringSpeed 23 22 -0.43%
BenchmarkHashBytesSpeed 44 42 -3.61%
BenchmarkHashStringArraySpeed 71 68 -4.05%
R=iant, khr
CC=gobot, golang-dev, google
https://golang.org/cl/9123046
Finer-grained transfers were relevant with per-M caches,
with per-P caches they are not relevant and harmful for performance.
For few small size classes where it makes difference,
it's fine to grab the whole span (4K).
benchmark old ns/op new ns/op delta
BenchmarkMalloc 42 40 -4.45%
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/9374043
The PKCS#1 spec requires that the PS padding in an RSA message be at
least 8 bytes long. We were not previously checking this. This isn't
important in the most common situation (session key encryption), but
the impact is unclear in other cases.
This change enforces the specified minimum size.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/9222045
OpenSSL can be configured to send empty records in order to randomise
the CBC IV. This is an early version of 1/n-1 record splitting (that Go
does) and is quite reasonable, but it results in tls.Conn.Read
returning (0, nil).
This change ignores up to 100 consecutive, empty records to avoid
returning (0, nil) to callers.
Fixes 5309.
R=golang-dev, r, minux.ma
CC=golang-dev
https://golang.org/cl/8852044
This patch resulted from a bit of quick optimisation in response to a
golang-nuts post. It looks like one could save a couple other copies in
this function, but this addresses the inner loop and is fairly simple.
benchmark old ns/op new ns/op delta
BenchmarkGCD10x10 1964 1711 -12.88%
BenchmarkGCD10x100 2019 1736 -14.02%
BenchmarkGCD10x1000 2471 2171 -12.14%
BenchmarkGCD10x10000 6040 5778 -4.34%
BenchmarkGCD10x100000 43204 43025 -0.41%
BenchmarkGCD100x100 11004 8520 -22.57%
BenchmarkGCD100x1000 11820 9446 -20.08%
BenchmarkGCD100x10000 23846 21382 -10.33%
BenchmarkGCD100x100000 133691 131505 -1.64%
BenchmarkGCD1000x1000 120041 95591 -20.37%
BenchmarkGCD1000x10000 136887 113600 -17.01%
BenchmarkGCD1000x100000 295370 273912 -7.26%
BenchmarkGCD10000x10000 2556126 2205198 -13.73%
BenchmarkGCD10000x100000 3159512 2808038 -11.12%
BenchmarkGCD100000x100000 150543094 139986045 -7.01%
R=gri, remyoudompheng
CC=bradfitz, gobot, golang-dev, gri
https://golang.org/cl/9424043
This is needed for preemptive scheduler,
it will preempt only when m->locks==0,
and we do not want to be preempted while
we have not completely unlocked the lock.
R=golang-dev, khr, iant
CC=golang-dev
https://golang.org/cl/9196047
Also change table type from int32[] to int8[] to save space in L1$.
benchmark old ns/op new ns/op delta
BenchmarkMalloc 42 40 -4.68%
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/9199044
Trying to lookup user's display name with directory services can
take several seconds when user's computer is not in a domain.
As a workaround, check if computer is joined in a domain first,
and don't use directory services if it is not.
Additionally, don't leak tokens in user.Current().
Fixes#5298.
R=golang-dev, bradfitz, alex.brainman, lucio.dere
CC=golang-dev
https://golang.org/cl/8541047
The *Encoder is almost always garbage. It doesn't need an
encodeState inside of it (and its bytes.Buffer), since it's
only needed locally inside of Encode.
benchmark old ns/op new ns/op delta
BenchmarkEncoderEncode 2562 2553 -0.35%
benchmark old bytes new bytes delta
BenchmarkEncoderEncode 283 102 -63.96%
R=r
CC=gobot, golang-dev
https://golang.org/cl/9365044
Move the documentation from race.go to doc.go, because
race.go uses +build race, so it's not normally parsed by go doc.
Rephrase the documentation for end users, provide link to race
detector manual.
Fixes#5444.
R=golang-dev, minux.ma, adg, r
CC=golang-dev
https://golang.org/cl/9144050
runtime.park() can access freed select descriptor
due to a racing free in another thread.
See the comment for details.
Slightly modified version of dvyukov's CL 9259045.
No test yet. Before this CL, the test described in issue 5422
would fail about every 40 times for me. With this CL, I ran
the test 5900 times with no failures.
Fixes#5422.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9311043
The linker can generate split stack prolog when a textflag 7 function
makes an indirect function call. If it happens, badsignal() crashes
trying to dereference g.
Fixes#5337.
R=bradfitz, dave, adg, iant, r, minux.ma
CC=adonovan, golang-dev
https://golang.org/cl/9226043
This must have been from when "error" was a good variable
name for an "os.Error". But we use "err" these days.
R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/9132045
runtime.setmg() calls another function (cgo_save_gm), so it must save
LR onto stack.
Re-enabled TestCthread test in misc/cgo/test.
Fixes#4863.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/9019043
The refcounting of driver Conns was completedly busted and
would leak (be held open forever) with any reasonable
load. This was a significant regression from Go 1.0.
The core of this patch is removing one line:
s.db.addDep(dc, s)
A database conn (dc) is a resource that be re-created any time
(but cached for speed) should not be held open forever with a
dependency refcount just because the Stmt (s) is alive (which
typically last for long periods of time, like forever).
The meat of the patch is new tests. In fixing the real issue,
a lot of tests then failed due to the fakedb_test.go's paranoia
about closing a fakeConn while it has open fakeStmts on it. I
could've ignored that, but that's been a problem in the past for
other bugs.
Instead, I now track per-Conn open statements and close them
when the the conn closes. The proper way to do this would've
been making *driverStmt a finalCloser and using the dep mechanism,
but it was much more invasive. Added a TODO instead.
I'd like to give a way for drivers to opt-out of caring about
driver.Stmt closes before a driver.Conn close, but that's a TODO
for the future, and that TODO is added in this CL.
I know this is very late for Go 1.1, but database/sql is
currently nearly useless without this.
I'd like to believe all these database/sql bugs in the past
release cycle are the result of increased usage, number of
drivers, and good feedback from increasingly-capable Go
developers, and not the result of me sucking. It's also hard
with all the real drivers being out-of-tree, so I'm having to
add more and more hooks to fakedb_test.go to simulate things
which real drivers end up doing.
Fixes#5323
R=golang-dev, snaury, gwenn.kahz, google, r
CC=golang-dev
https://golang.org/cl/8836045
It works on i386, but fails on amd64 and arm.
««« original CL description
runtime: prevent the GC from seeing the content of a frame in runfinq()
Fixes#5348.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/8954044
»»»
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8695051
Change the term 'standard time', which already means something,
to 'reference time', and add a couple of sentences and clarifications.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8799047
Also add a new variable ErrNoProgress that io.Readers can use to
report ineffectual Read calls.
Fixes#5310.
R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/8845043
Late bug fix, but this is arguably a regression from Go 1.0,
since we added this transparent decoding since then. Without
this fix, Go 1.0 users could decode this correctly, but Go 1.1
users would not be able to.
The newly added test is from the RFC itself.
The updated tests had the wrong "want" values before. They
were there to test \r\n vs \n equivalence (which is
unchanged), not leading whitespace.
The skipWhite decoder struct field was added in the battles of
Issue 4771 in revision b3bb265bfecf. It was just a wrong
strategy, from an earlier round of attempts in
https://golang.org/cl/7300092/
Update #4771Fixes#5295
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8536045
From the issue, which describes it as well as I could:
database/sql assumes that driver.Stmt.Close does not need the
connection.
see database/sql/sql.go:1308:
This puts the Rows' connection back into the idle pool, and
then calls the driver.Stmt.Close method of the Stmt it belongs
to. In the postgresql driver implementation
(https://github.com/lib/pq), Stmt.Close communicates with the
server (on the connection that was just put back into the idle
pool). Most of the time, this causes no problems, but if
another goroutine makes a query at the right (wrong?) time,
chaos results.
In any case, traffic is being sent on "free" connections
shortly after they are freed, leading to race conditions that
kill the driver code.
Fixes#5283
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8633044
This will let us ask people to rebuild the Go system without
precise GC, and then rebuild and retest their program, to see
if precise GC is causing whatever problem they are having.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8700043
UMTX_OP_WAIT expects that the address points to a uintptr, but
the code in lock_futex.c uses a uint32. UMTX_OP_WAIT_UINT is
just like UMTX_OP_WAIT, but the address points to a uint32.
This almost certainly makes no difference on a little-endian
system, but since the kernel supports it we should do the
right thing. And, who knows, maybe it matters.
R=golang-dev, bradfitz, r, ality
CC=golang-dev
https://golang.org/cl/8699043
The String method is called whenever the printing operation wants a string,
not just for %s and %v.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8638043
If there are no tags, the rules are the same as before.
If there is a tagged field, choose it if there is exactly one
at the top level of all fields.
More tests. The old tests were clearly inadequate, since
they all pass as is. The new tests only work with the new code.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/8617044
The old code was incorrect and also broken. It passed the tests by accident.
The new algorithm is:
1) Sort the fields in order of names.
2) For all fields with the same name, sort in increasing depth.
3) Choose the single field with shortest depth.
If any of the fields of a given name has a tag, do the above using
tagged fields of that name only.
Fixes#5245.
R=iant
CC=golang-dev
https://golang.org/cl/8583044
Makes it possible to return the spent runtime.PollDesc to
runtime.pollcache descriptor pool when netFD.connect or
syscall.Listen fails.
Fixes#5219.
R=dvyukov, dave, bradfitz, adg
CC=golang-dev
https://golang.org/cl/8318044
The race detector uses a global lock to analyze atomic
operations. A panic in the middle of the code leaves the
lock acquired.
Similarly, the sync package may leave the race detectro
inconsistent when methods are called on nil pointers.
R=golang-dev, r, minux.ma, dvyukov, rsc, adg
CC=golang-dev
https://golang.org/cl/7981043
It's not trivial to make a comprehensive check
due to inferior pointers, reflect, gob, etc.
But this is essentially what I've used to debug
the GC issues.
Update #5193.
R=golang-dev, iant, 0xe2.0x9a.0x9b, r
CC=golang-dev
https://golang.org/cl/8455043
The spec doesn't explicitly say that trailing data is okay, but a lot
of people do this and most unzippers will handle it just fine. In any
case, this makes the package more useful, and led me to make the
directory parsing code marginally more robust.
Fixes#5228.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/8504044
Use atomic operations on flags field to make sure we aren't
losing a flag update during parallel map operations.
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/8377046
It changes an exported API, and breaks the build.
««« original CL description
reflect: use unsafe.Pointer in StringHeader and SliceHeader
Relates to issue 5193.
R=r
CC=golang-dev
https://golang.org/cl/8363045
»»»
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8357051
The invariant is that there must be at least one running P or a thread polling network.
It was broken.
Fixes#5216.
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/8459043
This makes it an unsafe.Pointer in Go so the garbage collector
will treat it as a pointer to untyped data, not a pointer to
bytes.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/8286045
If for whatever reason seh points into Go heap region,
the dangling pointer will cause memory corruption during GC.
Update #5193.
R=golang-dev, alex.brainman, iant
CC=golang-dev
https://golang.org/cl/8402045
We've decided to leave logging to third-parties (there are too
many formats), which others have done.
And we can't change the behavior of the various response
fields at this point anyway. Plus I argue they're correct and
match their documention.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8391043
Fixes#5175.
Race detector runtime expects values passed to MapShadow() to be page-aligned,
because they are used in mmap() call. If they are not aligned mmap() trims
either beginning or end of the mapping.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8325043
- comment fixes
- s/z/x/ in (*rat).Float64 to match convention for functions
returning a non-*Rat
- minor test output tweaking
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8327044
The smtp package originally allowed PLAIN whenever, but then
the TLS check was added for paranoia, but it's too paranoid:
it prevents using PLAIN auth even from localhost to localhost
when the server advertises PLAIN support.
This CL also permits the client to send PLAIN if the server
advertises it.
Fixes#5184
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8279043
Save an allocation per GET request and don't call io.LimitedReader(r, 0)
just to read 0 bytes. There's already an eofReader global variable
for when we just want a non-nil io.Reader to immediately EOF.
(Sorry, I know Rob told me to stop, but I was bored on the plane and
wrote this before I received the recent "please, really stop" email.)
benchmark old ns/op new ns/op delta
BenchmarkServerHandlerTypeLen 13888 13279 -4.39%
BenchmarkServerHandlerNoLen 12912 12229 -5.29%
BenchmarkServerHandlerNoType 13348 12632 -5.36%
BenchmarkServerHandlerNoHeader 10911 10261 -5.96%
benchmark old allocs new allocs delta
BenchmarkServerHandlerTypeLen 20 19 -5.00%
BenchmarkServerHandlerNoLen 18 17 -5.56%
BenchmarkServerHandlerNoType 18 17 -5.56%
BenchmarkServerHandlerNoHeader 13 12 -7.69%
benchmark old bytes new bytes delta
BenchmarkServerHandlerTypeLen 1913 1878 -1.83%
BenchmarkServerHandlerNoLen 1878 1843 -1.86%
BenchmarkServerHandlerNoType 1878 1844 -1.81%
BenchmarkServerHandlerNoHeader 1085 1051 -3.13%
Fixes#5188
R=golang-dev, adg, r
CC=golang-dev
https://golang.org/cl/8297044
My old code was trying to be too smart.
Also: Slightly better error message format
for gofmt -r pattern errors.
Fixes#4406.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/8267045
This changes the map lookup behavior for string maps with 2-8 keys.
There was already previously a fastpath for 0 items and 1 item.
Now, if a string-keyed map has <= 8 items, first check all the
keys for length first. If only one has the right length, then
just check it for equality and avoid hashing altogether. Once
the map has more than 8 items, always hash like normal.
I don't know why some of the other non-string map benchmarks
got faster. This was with benchtime=2s, multiple times. I haven't
anything else getting slower, though.
benchmark old ns/op new ns/op delta
BenchmarkHashStringSpeed 37 34 -8.20%
BenchmarkHashInt32Speed 32 29 -10.67%
BenchmarkHashInt64Speed 31 27 -12.82%
BenchmarkHashStringArraySpeed 105 99 -5.43%
BenchmarkMegMap 274206 255153 -6.95%
BenchmarkMegOneMap 27 23 -14.80%
BenchmarkMegEqMap 148332 116089 -21.74%
BenchmarkMegEmptyMap 4 3 -12.72%
BenchmarkSmallStrMap 22 22 -0.89%
BenchmarkMapStringKeysEight_32 42 23 -43.71%
BenchmarkMapStringKeysEight_64 55 23 -56.96%
BenchmarkMapStringKeysEight_1M 279688 24 -99.99%
BenchmarkIntMap 16 15 -10.18%
BenchmarkRepeatedLookupStrMapKey32 40 37 -8.15%
BenchmarkRepeatedLookupStrMapKey1M 287918 272980 -5.19%
BenchmarkNewEmptyMap 156 130 -16.67%
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/7641057
It was unnecessarily cloning and then mutating a map that had
a very short lifetime (just that function).
No new tests, because they were added in revision 833bf2ef1527
(TestHeaderToWire). The benchmarks below are from the earlier
commit, revision 52e3407d.
I noticed this inefficiency when reviewing a change Peter Buhr
is looking into, which will also use these benchmarks.
benchmark old ns/op new ns/op delta
BenchmarkServerHandlerTypeLen 12547 12325 -1.77%
BenchmarkServerHandlerNoLen 12466 11167 -10.42%
BenchmarkServerHandlerNoType 12699 11800 -7.08%
BenchmarkServerHandlerNoHeader 11901 9210 -22.61%
benchmark old allocs new allocs delta
BenchmarkServerHandlerTypeLen 21 20 -4.76%
BenchmarkServerHandlerNoLen 20 18 -10.00%
BenchmarkServerHandlerNoType 20 18 -10.00%
BenchmarkServerHandlerNoHeader 17 13 -23.53%
benchmark old bytes new bytes delta
BenchmarkServerHandlerTypeLen 1930 1913 -0.88%
BenchmarkServerHandlerNoLen 1912 1879 -1.73%
BenchmarkServerHandlerNoType 1912 1878 -1.78%
BenchmarkServerHandlerNoHeader 1491 1086 -27.16%
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/8268046
The expected precision setting for the x87 on Win32 is 53-bit
but MinGW resets the floating point unit to 64-bit. Win32
object code generally expects values to be rounded to double,
not double extended, precision.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/8175044
Demonstrates one way to sort a slice of structs according
to different sort criteria, done in sequence.
One possible answer to a question that comes up often.
R=golang-dev, gri, bradfitz, adg, adg, rogpeppe
CC=golang-dev
https://golang.org/cl/8182044
Doing grow work on reads is not multithreaded safe.
Changed code to do grow work only on inserts & deletes.
This is a short-term fix, eventually we'll want to do
grow work in parallel to recover the space of the old
table.
Fixes#5120.
R=bradfitz, khr
CC=golang-dev
https://golang.org/cl/8242043
The text is printed only if the test fails or -test.v is set.
Document this behavior in the testing package and 'go help test'.
Also put a 'go install' into mkdoc.sh so I don't get tricked by the
process of updating the documentation ever again.
Fixes#5174.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/8118047
Closes the API documentation gap between platforms.
Also makes the code textual representation same between platforms.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8148043
Closes the API documentation gap between platforms.
Also makes the code textual representation same between platforms.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8147043
Since we can't properly handle anything except 100, treat all
1xx informational responses as sketchy and don't reuse the
connection for future requests.
The only other 1xx response code currently in use in the wild
is WebSockets' use of "101 Switching Protocols", but our
code.google.com/p/go.net/websockets doesn't use Client or
Transport: it uses ReadResponse directly, so is unaffected by
this CL. (and its tests still pass)
So this CL is entirely just future-proofing paranoia.
Also: the Internet is weird.
Update #2184
Update #3665
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/8208043
Whoops. I'm surprised it even worked before. (Need two pipes,
not one.)
Also, remove the whole pipe registration business, since it
wasn't even required in the previous version. (I'd later fixed
it at the end of send100Response, but forgot to delete it)
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8191044
This CL ensures we use the correct socket options for
passive and active open sockets.
For the passive open sockets created by Listen functions,
additional SO_REUSEADDR, SO_REUSEPORT options are required
for the quick service restart and/or multicasting.
For the active open sockets created by Dial functions, no
additional options are required.
R=golang-dev, dave, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/7795050
"There are only two hard problems in computer science:
cache invalidation, naming things, and off-by-one errors."
The HTTP server code already strips Expect: 100-continue on
requests, so httputil.ReverseProxy should be unaffected, but
some servers send unsolicited HTTP/1.1 100 Continue responses,
so we need to skip over them if they're seen to avoid getting
off-by-one on Transport requests/responses.
This does change the behavior of people who were using Client
or Transport directly and explicitly setting "Expect: 100-continue"
themselves, but it didn't work before anyway. Now instead of the
user code seeing a 100 response and then things blowing up, now
it basically works, except the Transport will still blast away
the full request body immediately. That's the part that needs
to be finished to close this issue.
This is the safe quick fix.
Update #3665
R=golang-dev, dsymonds, dave, jgrahamc
CC=golang-dev
https://golang.org/cl/8166045
This benchmark verifies that CL #8173043 reduces time spent
sliding the Buffer's contents.
Results without and with CL #8173043 applied:
benchmark old ns/op new ns/op delta
BenchmarkBufferFullSmallReads 755336 175054 -76.82%
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8174043
Also added a new benchmark from the same test:
benchmark old ns/op new ns/op delta
BenchmarkBufferNotEmptyWriteRead 2643698 709189 -73.17%
Fixes#5154
R=golang-dev, r, gri
CC=golang-dev
https://golang.org/cl/8164043
Adds the missing wildcard port assignment description to ListenUDP.
Also updates the wildcard port description on ListenTCP.
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/8063043
Also removes redundant tests that run Go 1.0 non-IPv6 support
Windows code on IPv6 enabled Windows kernels.
R=alex.brainman, golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/7812052
With the faster strings package, the difference between
the specialized code and strings.Split is in the noise:
benchmark old ns/op new ns/op delta
BenchmarkPrint 16724291 16686729 -0.22%
(Measured on a Mac Pro, 2.8GHz Quad-core Intel Xeon,
4GB 800 MHz DDR2, Mac OS X 10.8.3)
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8100044
Saves both the textproto.Reader allocation, and its internal
scratch buffer growing.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAliveLite 10324 10149 -1.70%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAliveLite 19 17 -10.53%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAliveLite 1559 1492 -4.30%
R=golang-dev, r, gri
CC=golang-dev
https://golang.org/cl/8094046
Removes another per-request allocation. Also makes the code more
readable, IMO. And more testable.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAliveLite 10539 10324 -2.04%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAliveLite 20 19 -5.00%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAliveLite 1609 1559 -3.11%
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/8118044
We already depend on strings in this file, so use it.
Plus strings.Index will be faster than a manual loop
once issue 3751 is finished.
R=golang-dev, khr
CC=golang-dev
https://golang.org/cl/8116043
A chunkWriter and a response are 1:1. Make them contiguous in
memory and save an allocation.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAliveLite 10715 10539 -1.64%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAliveLite 21 20 -4.76%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAliveLite 1626 1609 -1.05%
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/8114043
Add more tests around the various orders handlers can access
and flush response headers.
Also clarify the documentation on fields of response and
chunkWriter.
While there, remove an allocation (a header clone) for simple
handlers.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAliveLite 15245 14966 -1.83%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAliveLite 24 23 -4.17%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAliveLite 1717 1668 -2.85%
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/8101043
Motivated by garbage profiling in HTTP benchmarks. This
changes means new empty maps are just one small allocation
(the HMap) instead the HMap + the relatively larger h->buckets
allocation. This helps maps which remain empty throughout
their life.
benchmark old ns/op new ns/op delta
BenchmarkNewEmptyMap 196 107 -45.41%
benchmark old allocs new allocs delta
BenchmarkNewEmptyMap 2 1 -50.00%
benchmark old bytes new bytes delta
BenchmarkNewEmptyMap 195 50 -74.36%
R=khr, golang-dev, r
CC=golang-dev
https://golang.org/cl/7722046
There was another bufio.Writer not being reused, found with
GOGC=off and -test.memprofile.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnWithKeepAlive 18270 16046 -12.17%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnWithKeepAlive 38 36 -5.26%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnWithKeepAlive 4598 2488 -45.89%
Update #5100
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/8038047
A HMUL node appears in some constant divisions, but
to observe a false negative in race detector the divisor must be
suitably chosen to make sure the only memory access is
done for HMUL.
R=dvyukov
CC=golang-dev
https://golang.org/cl/7935045
For Go 1.1, stop checking the rlimit, because it broke now
that mheap is allocated using SysAlloc. See issue 5049.
R=r
CC=golang-dev
https://golang.org/cl/7741050
The arm gentraceback mishandled frame linkage values pointing
to the assembly return function. This function is special as
its frame size is zero and it contains only one instruction.
These conditions would preserve the frame pointer and result
in an off by one error when unwinding the caller.
Fixes#5124
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8023043
Prevents storm of error messages if something goes wrong.
In the case of issue 5073 the epoll fd was closed by the test.
Update #5073.
R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/7966043
This CL avoids test data sharing in repetitive test runs;
e.g., go test net -cpu=1,1,1
R=golang-dev, fullung, bradfitz
CC=golang-dev
https://golang.org/cl/8011043
Handle interface comparison correctly,
add a few more tests, mark more nodes as impossible.
R=dvyukov, golang-dev
CC=golang-dev
https://golang.org/cl/7942045
Make the copy directly in the convert switch instead of an extra loop.
Also stops converting nil-[]byte to zero-[]byte when assigning to *interface
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7962044
At some point in the past, I believe the GCD algorithm was setting d to
be negative. The RSA code has been correcting that ever since but, now,
it appears to have changed and the correction isn't needed.
Having d be too large is harmless, it's just a little odd and I
happened to notice.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7948044
This keeps the logic about how to set the thread-local variables
m and g in code compiled and linked by the gc toolchain,
an important property for upcoming cgo changes.
It's also just a nice cleanup: one less place to update when
these details change.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7560048
The right operand of a && and || is only executed conditionnally,
so the instrumentation must be more careful. In particular
it should not turn nodes assumed to be cheap after walk into
expensive ones.
Update #4228
R=dvyukov, golang-dev
CC=golang-dev
https://golang.org/cl/7986043
The ARM implementation of runtime.cgocallback_gofunc diverged
from the calling convention by leaving a word of garbage at
the top of the stack and storing the return PC above the
locals. This change stores the return PC at the top of the
stack and removes the save area above the locals.
Update #5124
This CL fixes first part of the ARM issues and added the unwind test.
R=golang-dev, bradfitz, minux.ma, cshapiro, rsc
CC=golang-dev
https://golang.org/cl/7728045
The edit makes Hypot's description match the form
used in the other routines in this package.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/8003046
Adds the new debugging constant 'checkgc'. If its value is non-zero
all calls to mallocgc() from hashmap.c will start a garbage collection.
Fixes#5074.
R=golang-dev, khr
CC=golang-dev, rsc
https://golang.org/cl/7663051
Fixes performance of the current windows network poller
with the new scheduler.
Gives runtime a hint when GetQueuedCompletionStatus() will block.
Fixes#5068.
benchmark old ns/op new ns/op delta
BenchmarkTCP4Persistent 4004000 33906 -99.15%
BenchmarkTCP4Persistent-2 21790 17513 -19.63%
BenchmarkTCP4Persistent-4 44760 34270 -23.44%
BenchmarkTCP4Persistent-6 45280 43000 -5.04%
R=golang-dev, alex.brainman, coocood, rsc
CC=golang-dev
https://golang.org/cl/7612045
This CL updates CL 7511043;
- adds new test cases for both UDPConn and UnixConn,
- makes sure unnamed UnixAddr handling,
- replaces t.Errorf with t.Fatalf in sockname related test cases.
Fixes#3721 (again).
Fixes#3838 (again).
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7627048
I'm not sure how to write a test for this. The change in
behaviour is that if you somehow get a SIGBUS signal for an
address >= 0x1000, the program will now crash rather than
calling panic. As far as I know, on x86 GNU/Linux, the only
way to get a SIGBUS (rather than a SIGSEGV) is to set the
stack pointer to an invalid value.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7906045
E.g conversions from numeric types to RawBytes are missing, what makes RawBytes unusable in some cases.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7783046
The GIF89a spec says: "Each image must fit within the
boundaries of the Logical Screen, as defined in the
Logical Screen Descriptor." Also, do not accept
GIFs which have too much data for the image size.
R=nigeltao, jra, r
CC=bradfitz, golang-dev
https://golang.org/cl/7602045
On Darwin and FreeBSD, the mmap syscall return value is returned
unmodified. This means that the return value will either be a
valid address or a positive error number.
Also check return value from mmap in SysReserve - the callers of
SysReserve expect nil to be returned if the allocation failed.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7871043
Rather than just checking for ENOMEM, check for a return value of less
than 4096, so that we catch other errors such as EACCES and EINVAL.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7942043
Saves over 8KB of allocations per new connection.
benchmark old ns/op new ns/op delta
BenchmarkServerFakeConnNoKeepAlive 28777 24927 -13.38%
benchmark old allocs new allocs delta
BenchmarkServerFakeConnNoKeepAlive 52 46 -11.54%
benchmark old bytes new bytes delta
BenchmarkServerFakeConnNoKeepAlive 13716 5286 -61.46%
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7799047
After the revert of revision 9ea9e7e6e0c8
the related revision 76ff7da868c6 must be reverted too.
Fixes#5102.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7961044
If a handler didn't consume all its Request.Body, child.go was
closing the socket while the host was still writing to it,
causing the child to send a RST and the host (at least nginx)
to send an empty response body.
Now, we tell the host we're done with the request/response
first, and then close our input pipe after consuming a bit of
it. Consuming the body fixes the problem, and flushing to the
host first to tell it that we're done increases the chance
that the host cuts off further data to us, meaning we won't
have much to consume.
No new tests, because this package is lacking in tests.
Tested by hand with nginx. See issue for testing details.
Fixes#4183
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7939045
Also adjust the implementation of applyRelocationsAMD64
so that the test added in CL 6848044 still passes.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7686049
XOR key into data 128 bits at a time instead of 64 bits
and pipeline half of state loads. Rotate loop to allow
single-register indexing for state[i].
On a MacBookPro10,2 (Core i5):
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 412 224 -45.63%
BenchmarkRC4_1K 3179 1613 -49.26%
BenchmarkRC4_8K 25223 12545 -50.26%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 310.51 570.42 1.84x
BenchmarkRC4_1K 322.09 634.48 1.97x
BenchmarkRC4_8K 320.97 645.32 2.01x
For comparison, on the same machine, openssl 0.9.8r reports
its rc4 speed as somewhat under 350 MB/s for both 1K and 8K
(it is operating 64 bits at a time).
On an Intel Xeon E5520:
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 418 259 -38.04%
BenchmarkRC4_1K 3200 1884 -41.12%
BenchmarkRC4_8K 25173 14529 -42.28%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 306.04 492.48 1.61x
BenchmarkRC4_1K 319.93 543.26 1.70x
BenchmarkRC4_8K 321.61 557.20 1.73x
For comparison, on the same machine, openssl 1.0.1
reports its rc4 speed as 587 MB/s for 1K and 601 MB/s for 8K.
R=agl
CC=golang-dev
https://golang.org/cl/7865046
-- amd64 --
On a MacBookPro10,2 (Core i5):
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 470 421 -10.43%
BenchmarkRC4_1K 3123 3275 +4.87%
BenchmarkRC4_8K 26351 25866 -1.84%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 272.22 303.40 1.11x
BenchmarkRC4_1K 327.80 312.58 0.95x
BenchmarkRC4_8K 307.24 313.00 1.02x
For comparison, on the same machine, openssl 0.9.8r reports
its rc4 speed as somewhat under 350 MB/s for both 1K and 8K.
The Core i5 performance can be boosted another 20%, but only
by making the Xeon performance significantly slower.
On an Intel Xeon E5520:
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 774 417 -46.12%
BenchmarkRC4_1K 6121 3200 -47.72%
BenchmarkRC4_8K 48394 25151 -48.03%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 165.18 306.84 1.86x
BenchmarkRC4_1K 167.28 319.92 1.91x
BenchmarkRC4_8K 167.29 321.89 1.92x
For comparison, on the same machine, openssl 1.0.1
(which uses a different implementation than 0.9.8r)
reports its rc4 speed as 587 MB/s for 1K and 601 MB/s for 8K.
It is using SIMD instructions to do more in parallel.
So there's still some improvement to be had, but even so,
this is almost 2x faster than what it replaced.
-- 386 --
On a MacBookPro10,2 (Core i5):
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 3491 421 -87.94%
BenchmarkRC4_1K 28063 3205 -88.58%
BenchmarkRC4_8K 220392 25228 -88.55%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 36.66 303.81 8.29x
BenchmarkRC4_1K 36.49 319.42 8.75x
BenchmarkRC4_8K 36.73 320.90 8.74x
On an Intel Xeon E5520:
benchmark old ns/op new ns/op delta
BenchmarkRC4_128 2268 524 -76.90%
BenchmarkRC4_1K 18161 4137 -77.22%
BenchmarkRC4_8K 142396 32350 -77.28%
benchmark old MB/s new MB/s speedup
BenchmarkRC4_128 56.42 244.13 4.33x
BenchmarkRC4_1K 56.38 247.46 4.39x
BenchmarkRC4_8K 56.86 250.26 4.40x
R=agl
CC=golang-dev
https://golang.org/cl/7547050
Fixes#5061.
Current code relies on the fact that fd's are automatically removed from epoll set when closed. However, it is not true. Underlying file description is removed from epoll set only when *all* fd's referring to it are closed.
There are 2 bad consequences:
1. Kernel delivers notifications on already closed fd's.
2. The following sequence of events leads to error:
- add fd1 to epoll
- dup fd1 = fd2
- close fd1 (not removed from epoll since we've dup'ed the fd)
- dup fd2 = fd1 (get the same fd as fd1)
- add fd1 to epoll = EEXIST
So, if fd can be potentially dup'ed of fork'ed, it's necessary to explicitly remove the fd from epoll set.
R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/7870043
Add missing CLOSUREVAR in switch.
Mark MAKE, string conversion nodes as impossible.
Control statements do not need instrumentation.
Instrument COM and LROT nodes.
Instrument map length.
Update #4228
R=dvyukov, golang-dev
CC=golang-dev
https://golang.org/cl/7504047
Hashtable is arranged as an array of
8-entry buckets with chained overflow.
Each bucket has 8 extra hash bits
per key to provide quick lookup within
a bucket. Table is grown incrementally.
Update #3885
Go time drops from 0.51s to 0.34s.
R=r, rsc, m3b, dave, bradfitz, khr, ugorji, remyoudompheng
CC=golang-dev
https://golang.org/cl/7504044
Found this inconsistency from net/http's Server while
debugging Issue 4183
Unfortunately this package lacks testing around this,
or most of child.go. :/
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7735046
No net package involved. And with ReportAllocs we can see
how much garbage is created per request.
R=adg, dave
CC=golang-dev
https://golang.org/cl/7913044
Inserting a key-value pair into a hashmap storing keys or values
indirectly can cause the garbage collector to find the hashmap in
an inconsistent state.
Fixes#5074.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7913043
- A note doesn't have to be in the first
comment of a comment group anymore, and
several notes may appear in the same comment
group (e.g., it is fairly common to have a
TODO(uid) note immediately following another
comment).
- Define a doc.Note type which also contains
note uid and position info.
- Better formatting in godoc output. The position
information is not yet used, but could be used to
locate the note in the source text if desired.
Fixes#4843.
R=r, cnicolaou
CC=gobot, golang-dev
https://golang.org/cl/7496048
On NetBSD tv_sec is already an int64 so no need for a test.
On OpenBSD, semasleep expects a Unix time as argument,
and 1<<30 is in 2004.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7810044
The example is the same as the FileServer one, but
it's relevant for both.
Also use strings.TrimPrefix while I'm here.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7598046
Now that revision 0c029965805f is in, it's easy
to guarantee that we never access a driver.Conn
concurrently, per the database/sql/driver contract,
so we can remove this overlarge mutex.
Fixes#3857
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7707047
If LookPath in Command fails, sets a sticky error, and then
StdinPipe, StdoutPipe, or StderrPipe were called, those pipe
fds were never cleaned up.
Fixes#5071
R=golang-dev, rogpeppe
CC=golang-dev
https://golang.org/cl/7799046
The current SysAlloc implementation suffers from a signed vs unsigned
comparision bug. Since the error code from mmap is negated, the
unsigned comparision of v < 4096 is always false on error. Fix this
by switching to the darwin/freebsd/linux mmap model and leave the mmap
return value unmodified.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7870044
Avoids printing it every time we ask a question about the package from
the command line.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7789048