The work buffer management used by the garbage
collector during parallel collections leaks buffers.
This CL tests for and fixes the leak.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/5254059
Use FlagNoPointers and do not zeroize memory when allocate strings.
test/garbage/parser.out old new
run #1 32.923s 32.065s
run #2 33.047s 31.931s
run #3 32.702s 31.841s
run #4 32.718s 31.838s
run #5 32.702s 31.868s
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5259041
Implement a locking model based on the current linux model - a
tri-state mutex with active spinning, passive spinning and sleeping.
R=golang-dev, dvyukov, rsc
CC=golang-dev
https://golang.org/cl/4974043
The malloc sample trigger was not being set in a
new m, so the first allocation in each new m - the
goroutine structure - was being sampled with
probability 1 instead of probability sizeof(G)/rate,
an oversampling of about 5000x for the default
rate of 1 MB. This bug made pprof graphs show
far more G allocations than there actually were.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5224041
Fixes#2337.
Unfortunate sequence of events is:
1. maxcpu=2, mcpu=1, grunning=1
2. starttheworld creates an extra M:
maxcpu=2, mcpu=2, grunning=1
4. the goroutine calls runtime.GOMAXPROCS(1)
maxcpu=1, mcpu=2, grunning=1
5. since it sees mcpu>maxcpu, it calls gosched()
6. schedule() deschedules the goroutine:
maxcpu=1, mcpu=1, grunning=0
7. schedule() call getnextandunlock() which
fails to pick up the goroutine again,
because canaddcpu() fails, because mcpu==maxcpu
8. then it sees that grunning==0,
reports deadlock and terminates
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5191044
When ncpu < 2, work.nproc is always 1 which results in infinite helper
threads being created if gomaxprocs > 1 and MaxGcproc > 1. Avoid this
by using the same limits as imposed helpgc().
R=golang-dev, rsc, dvyukov
CC=golang-dev
https://golang.org/cl/5176044
This change adds the osyield and usleep
functions and code to read the number of
processors from /dev/sysstat.
I also changed SysAlloc to return nil
when brk fails (it was returning -1).
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5177049
The map implementation was using the C idiom of using
a pointer just past the end of its table as a limit pointer.
Unfortunately, the garbage collector sees that pointer as
pointing at the block adjacent to the map table, pinning
in memory a block that would otherwise be freed.
Fix by making limit pointer point at last valid entry, not
just past it.
Reviewed by Mike Burrows.
R=golang-dev, bradfitz, lvd, r
CC=golang-dev
https://golang.org/cl/5158045
Running test/garbage/parser.out.
On a 4-core Lenovo X201s (Linux):
31.12u 0.60s 31.74r 1 cpu, no atomics
32.27u 0.58s 32.86r 1 cpu, atomic instructions
33.04u 0.83s 27.47r 2 cpu
On a 16-core Xeon (Linux):
33.08u 0.65s 33.80r 1 cpu, no atomics
34.87u 1.12s 29.60r 2 cpu
36.00u 1.87s 28.43r 3 cpu
36.46u 2.34s 27.10r 4 cpu
38.28u 3.85s 26.92r 5 cpu
37.72u 5.25s 26.73r 6 cpu
39.63u 7.11s 26.95r 7 cpu
39.67u 8.10s 26.68r 8 cpu
On a 2-core MacBook Pro Core 2 Duo 2.26 (circa 2009, MacBookPro5,5):
39.43u 1.45s 41.27r 1 cpu, no atomics
43.98u 2.95s 38.69r 2 cpu
On a 2-core Mac Mini Core 2 Duo 1.83 (circa 2008; Macmini2,1):
48.81u 2.12s 51.76r 1 cpu, no atomics
57.15u 4.72s 51.54r 2 cpu
The handoff algorithm is really only good for two cores.
Beyond that we will need to so something more sophisticated,
like have each core hand off to the next one, around a circle.
Even so, the code is a good checkpoint; for now we'll limit the
number of gc procs to at most 2.
R=dvyukov
CC=golang-dev
https://golang.org/cl/4641082
The Dwarf info has the full typenames, the go *struct runtime.commonType
has the short name. A more permanent fix would link the two together
but this way the user gets useable stack traces for now.
R=rsc
CC=golang-dev
https://golang.org/cl/5097046
gotest src/pkg/exp/template/html was crashing because the exception handler overflowed the goroutine stack.
R=alex.brainman, golang-dev
CC=golang-dev
https://golang.org/cl/5031049
The Windows implementation of the net package churns through a couple of channels for every read/write operation. This translates into a lot of time spent in the kernel creating and deleting event objects.
R=rsc, dvyukov, alex.brainman, jp
CC=golang-dev
https://golang.org/cl/4997044
My string literal was being rewritten from
"runtime.SysReserve(%p, %D) = error %d"
to
"runtime.SysReserve ( %p , %D ) = error %d"
R=iant
CC=golang-dev
https://golang.org/cl/4972051
- Rename sys_sched_yield() to osyield() as this is now defined in asm.h.
- Only print kern.rtheads message if rfork_thread() failed with ENOTSUP.
- Remove unused variables.
R=rsc
CC=golang-dev
https://golang.org/cl/4973043
cdecl calbacks have been implemented in C/ASM code, just Go function is missing
R=golang-dev, alex.brainman
CC=golang-dev
https://golang.org/cl/4969047
Make the stack traces more readable for new
Go programmers while preserving their utility for old hands.
- Change status number [4] to string.
- Elide frames in runtime package (internal details).
- Swap file:line and arguments.
- Drop 'created by' for main goroutine.
- Show goroutines in order of allocation:
implies main goroutine first if nothing else.
There is no option to get the extra frames back.
Uncomment 'return 1' at the bottom of symtab.c.
$ 6.out
throw: all goroutines are asleep - deadlock!
goroutine 1 [chan send]:
main.main()
/Users/rsc/g/go/src/pkg/runtime/x.go:22 +0x8a
goroutine 2 [select (no cases)]:
main.sel()
/Users/rsc/g/go/src/pkg/runtime/x.go:11 +0x18
created by main.main
/Users/rsc/g/go/src/pkg/runtime/x.go:19 +0x23
goroutine 3 [chan receive]:
main.recv(0xf8400010a0, 0x0)
/Users/rsc/g/go/src/pkg/runtime/x.go:15 +0x2e
created by main.main
/Users/rsc/g/go/src/pkg/runtime/x.go:20 +0x50
goroutine 4 [chan receive (nil chan)]:
main.recv(0x0, 0x0)
/Users/rsc/g/go/src/pkg/runtime/x.go:15 +0x2e
created by main.main
/Users/rsc/g/go/src/pkg/runtime/x.go:21 +0x66
$
$ 6.out index
panic: runtime error: index out of range
goroutine 1 [running]:
main.main()
/Users/rsc/g/go/src/pkg/runtime/x.go:25 +0xb9
$
$ 6.out nil
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x22ca]
goroutine 1 [running]:
main.main()
/Users/rsc/g/go/src/pkg/runtime/x.go:28 +0x211
$
$ 6.out panic
panic: panic
goroutine 1 [running]:
main.main()
/Users/rsc/g/go/src/pkg/runtime/x.go:30 +0x101
$
R=golang-dev, qyzhai, n13m3y3r, r
CC=golang-dev
https://golang.org/cl/4907048
Allocate Defer on stack during cgo calls, as suggested
by dvyukov. Also includes some comment corrections.
benchmark old,ns/op new,ns/op
BenchmarkCgoCall 669 330
(Intel Xeon CPU 1.80GHz * 4, Linux 386)
R=dvyukov, rsc
CC=golang-dev
https://golang.org/cl/4910041
The corruption can occur when GOMAXPROCS
is changed from >1 to 1, since GOMAXPROCS=1
does not imply there is only 1 goroutine running,
other goroutines can still be not parked after
the change.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4873050
Every time we enter callback from Windows, it is
possible that go exception handler is not at the top
of per-thread exception handlers chain. So it needs
to be installed again. At this moment this is done
by replacing top SEH frame with SEH frame as at time
of syscall for the time of callback. This is incorrect,
because, if exception strike, we won't be able to call
any exception handlers installed inside syscall,
because they are not in the chain. This changes
procedure to add new SEH frame on top of existing
chain instead.
I also removed m sehframe field, because I don't
think it is needed. We use single global exception
handler everywhere.
R=golang-dev, r
CC=golang-dev, hectorchu
https://golang.org/cl/4832060
Add support for the go runtime on openbsd/amd64. This is based on
the existing freebsd runtime.
Threads are implemented using OpenBSD's rthreads, which are currently
disabled by default, however can be enabled via the kern.rthreads
sysctl.
For now, cgo is disabled.
R=rsc
CC=golang-dev
https://golang.org/cl/4815067
The change adds specialized type algorithms
for slices and types of size 8/16/32/64/128.
It significantly accelerates chan and map operations
for most builtin types as well as user structs.
benchmark old,ns/op new,ns/op
BenchmarkChanUncontended 226 94
(on Intel Xeon E5620, 2.4GHz, Linux 64 bit)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4815087
The data race can lead to reads of partially
initialized concurrently mutated symbol data.
The change also adds a simple sanity test
for Caller() and FuncForPC().
R=rsc
CC=golang-dev
https://golang.org/cl/4817058
When rnd is called with a second argument of 1, it simply
returns the first argument anyway.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4820045
Replace cas with xadd in scheduler.
Suggested by Dmitriy in last code review.
Verified with Promela model.
When there's actual contention for the atomic word,
this avoids the looping that compare-and-swap requires.
benchmark old ns/op new ns/op delta
runtime_test.BenchmarkSyscall 32 26 -17.08%
runtime_test.BenchmarkSyscall-2 155 59 -61.81%
runtime_test.BenchmarkSyscall-3 112 52 -52.95%
runtime_test.BenchmarkSyscall-4 94 48 -48.57%
runtime_test.BenchmarkSyscallWork 871 872 +0.11%
runtime_test.BenchmarkSyscallWork-2 481 477 -0.83%
runtime_test.BenchmarkSyscallWork-3 338 335 -0.89%
runtime_test.BenchmarkSyscallWork-4 263 256 -2.66%
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/4800047
Drops mallocrep1.go back to a reasonable
amount of time. (154 -> 0.8 seconds on my Mac)
Fixes#2085.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/4811045
Remove complicated PRNG algorithm
(argument is limited by uint16 and can't be <= 1).
Do not require chansend/chanrecv selgen to be bumped with CAS.
R=rsc, ken
CC=golang-dev
https://golang.org/cl/4816041
pkg/runtime/Makefile:
. Adjusted so "goc2c.c" is built using the Plan 9 libraries.
pkg/runtime/goc2c.c:
. Added/subtracted #include headers to correspond to Plan 9
toolkit.
. Changed fprintf(stderr,...)/exit() combinations to
sysfatal() calls, adjusted the "%u" format to "%ud".
. Added exits(0) at the end of main().
. Made main() a void-returning function and removed the
"return 0" at the end of it.
Tested on UBUNTU and Plan 9 only.
R=r, rsc
CC=golang-dev
https://golang.org/cl/4626093
Used to use mcpu+msyscall but that's
problematic for packing into a single
atomic word. The running goroutine count
(where running == Go code or syscall)
can be maintained separately, always
manipulated under lock.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4767041
