This change adds support for serving and receiving Signed Certificate
Timestamps as described in RFC 6962.
The server is now capable of serving SCTs listed in the Certificate
structure. The client now asks for SCTs and, if any are received,
they are exposed in the ConnectionState structure.
Fixes#10201
Change-Id: Ib3adae98cb4f173bc85cec04d2bdd3aa0fec70bb
Reviewed-on: https://go-review.googlesource.com/8988
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Jonathan Rudenberg <jonathan@titanous.com>
Currently parseRecord will always start with a nil
slice and then resize the slice on append. For input
with a fixed number of fields per record we can preallocate
the slice to avoid having to resize the slice.
This change implements this optimization by using
FieldsPerRecord as capacity if it's > 0 and also adds a
benchmark to better show the differences.
benchmark old ns/op new ns/op delta
BenchmarkRead 19741 17909 -9.28%
benchmark old allocs new allocs delta
BenchmarkRead 59 41 -30.51%
benchmark old bytes new bytes delta
BenchmarkRead 6276 5844 -6.88%
Change-Id: I7c2abc9c80a23571369bcfcc99a8ffc474eae7ab
Reviewed-on: https://go-review.googlesource.com/8880
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Follows the linux signal forwarding semantics from
http://golang.org/cl/8712, sharing the implementation of sigfwdgo.
Forwarding for 386, arm, and arm64 will follow.
Change-Id: I6bf30d563d19da39b6aec6900c7fe12d82ed4f62
Reviewed-on: https://go-review.googlesource.com/9302
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is largely cosmetic in the sense that it is the remnants
of a change proposal I had prepared for testing/quick, until I
discovered that 3e9ed27 already implemented the feature I was looking
for: quick.Value() for reflect.Kind Array. What you see is a merger
and manual cleanup; the cosmetic cleanups are as follows:
(1.) Keeping the TestCheckEqual and its associated input functions
in the same order as type kinds defined in reflect.Kind. Since
3e9ed27 was committed, the test case began to diverge from the
constant's ordering.
(2.) The `Intptr` derivatives existed to exercise quick.Value with
reflect.Kind's `Ptr` constant. All `Intptr` (unrelated to `uintptr`)
in the test have been migrated to ensure the parallelism of the
listings and to convey that `Intptr` is not special.
(3.) Correct a misspelling (transposition) of "alias", whereby it is
named as "Alais".
Change-Id: I441450db16b8bb1272c52b0abcda3794dcd0599d
Reviewed-on: https://go-review.googlesource.com/8804
Reviewed-by: Russ Cox <rsc@golang.org>
The long comment block in obj6.go:progedit talked about the two code sequences
for accessing g as "local exec" and "initial exec", but really they are both forms
of local exec. This stuff is confusing enough without using the wrong words for
things, so rewrite it to talk about 2-instruction and 1-instruction sequences.
Unfortunately the confusion has made it into code, with the R_TLS_IE relocation
now doing double duty as meaning actual initial exec when externally linking and
boring old local exec when linking internally (half of this is my fault). So this
stops using R_TLS_IE in the local exec case. There is a chance this might break
plan9 or windows, but I don't think so. Next step is working out what the heck is
going on on ARM...
Change-Id: I09da4388210cf49dbc99fd25f5172bbe517cee57
Reviewed-on: https://go-review.googlesource.com/9273
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
A previous change to mbitmap.go dropped a return on a
path the seems not to be excersized. This was a mistake that
this CL fixes.
Change-Id: I715ee4ef08f5bf8d9f53cee84e8fb31a237e2d43
Reviewed-on: https://go-review.googlesource.com/9295
Reviewed-by: Austin Clements <austin@google.com>
I think this should fix the arm build. A proper fix involves making the handling
of tlsg less fragile, I'll try that tomorrow.
Update #10557
Change-Id: I9b1b666737fb40aebb6f284748509afa8483cce5
Reviewed-on: https://go-review.googlesource.com/9272
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
Currently, each M has a cache of the most recently used *workbuf. This
is used primarily by the write barrier so it doesn't have to access
the global workbuf lists on every write barrier. It's also used by
stack scanning because it's convenient.
This cache is important for write barrier performance, but this
particular approach has several downsides. It's faster than no cache,
but far from optimal (as the benchmarks below show). It's complex:
access to the cache is sprinkled through most of the workbuf list
operations and it requires special care to transform into and back out
of the gcWork cache that's actually used for scanning and marking. It
requires atomic exchanges to take ownership of the cached workbuf and
to return it to the M's cache even though it's almost always used by
only the current M. Since it's per-M, flushing these caches is O(# of
Ms), which may be high. And it has some significant subtleties: for
example, in general the cache shouldn't be used after the
harvestwbufs() in mark termination because it could hide work from
mark termination, but stack scanning can happen after this and *will*
use the cache (but it turns out this is okay because it will always be
followed by a getfull(), which drains the cache).
This change replaces this cache with a per-P gcWork object. This
gcWork cache can be used directly by scanning and marking (as long as
preemption is disabled, which is a general requirement of gcWork).
Since it's per-P, it doesn't require synchronization, which simplifies
things and means the only atomic operations in the write barrier are
occasionally fetching new work buffers and setting a mark bit if the
object isn't already marked. This cache can be flushed in O(# of Ps),
which is generally small. It follows a simple flushing rule: the cache
can be used during any phase, but during mark termination it must be
flushed before allowing preemption. This also makes the dispose during
mutator assist no longer necessary, which eliminates the vast majority
of gcWork dispose calls and reduces contention on the global workbuf
lists. And it's a lot faster on some benchmarks:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 11963668673 11206112763 -6.33%
BenchmarkFannkuch11 2643217136 2649182499 +0.23%
BenchmarkFmtFprintfEmpty 70.4 70.2 -0.28%
BenchmarkFmtFprintfString 364 307 -15.66%
BenchmarkFmtFprintfInt 317 282 -11.04%
BenchmarkFmtFprintfIntInt 512 483 -5.66%
BenchmarkFmtFprintfPrefixedInt 404 380 -5.94%
BenchmarkFmtFprintfFloat 521 479 -8.06%
BenchmarkFmtManyArgs 2164 1894 -12.48%
BenchmarkGobDecode 30366146 22429593 -26.14%
BenchmarkGobEncode 29867472 26663152 -10.73%
BenchmarkGzip 391236616 396779490 +1.42%
BenchmarkGunzip 96639491 96297024 -0.35%
BenchmarkHTTPClientServer 100110 70763 -29.31%
BenchmarkJSONEncode 51866051 52511382 +1.24%
BenchmarkJSONDecode 103813138 86094963 -17.07%
BenchmarkMandelbrot200 4121834 4120886 -0.02%
BenchmarkGoParse 16472789 5879949 -64.31%
BenchmarkRegexpMatchEasy0_32 140 140 +0.00%
BenchmarkRegexpMatchEasy0_1K 394 394 +0.00%
BenchmarkRegexpMatchEasy1_32 120 120 +0.00%
BenchmarkRegexpMatchEasy1_1K 621 614 -1.13%
BenchmarkRegexpMatchMedium_32 209 202 -3.35%
BenchmarkRegexpMatchMedium_1K 54889 55175 +0.52%
BenchmarkRegexpMatchHard_32 2682 2675 -0.26%
BenchmarkRegexpMatchHard_1K 79383 79524 +0.18%
BenchmarkRevcomp 584116718 584595320 +0.08%
BenchmarkTemplate 125400565 109620196 -12.58%
BenchmarkTimeParse 386 387 +0.26%
BenchmarkTimeFormat 580 447 -22.93%
(Best out of 10 runs. The delta of averages is similar.)
This also puts us in a good position to flush these caches when
nearing the end of concurrent marking, which will let us increase the
size of the work buffers while still controlling mark termination
pause time.
Change-Id: I2dd94c8517a19297a98ec280203cccaa58792522
Reviewed-on: https://go-review.googlesource.com/9178
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
When findRunnable considers running a fractional mark worker, it first
checks if there's any work to be done; if there isn't there's no point
in running the worker because it will just reschedule immediately.
However, currently findRunnable just checks work.full and
work.partial, whereas getfull can *also* draw work from m.currentwbuf.
As a result, findRunnable may not start a worker even though there
actually is work.
This problem manifests itself in occasional failures of the
test/init1.go test. This test is unusual because it performs a large
amount of allocation without executing any write barriers, which means
there's nothing to force the pointers in currentwbuf out to the
work.partial/full lists where findRunnable can see them.
This change fixes this problem by making findRunnable also check for a
currentwbuf. This aligns findRunnable with trygetfull's notion of
whether or not there's work.
Change-Id: Ic76d22b7b5d040bc4f58a6b5975e9217650e66c4
Reviewed-on: https://go-review.googlesource.com/9299
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, findRunnable only considers running a mark worker if
there's work in the work queue. In principle, this can delay the start
of the desired number of dedicated mark workers if there's no work
pending. This is unlikely to occur in practice, since there should be
work queued from the scan phase, but if it were to come up, a CPU hog
mutator could slow down or delay garbage collection.
This check makes sense for fractional mark workers, since they'll just
return to the scheduler immediately if there's no work, but we want
the scheduler to start all of the dedicated mark workers promptly,
even if there's currently no queued work. Hence, this change moves the
pending work check after the check for starting a dedicated worker.
Change-Id: I52b851cc9e41f508a0955b3f905ca80f109ea101
Reviewed-on: https://go-review.googlesource.com/9298
Reviewed-by: Rick Hudson <rlh@golang.org>
Instead of comparing against the entire output that may include
verbose warning messages, use the last line of the output and check
it includes the expected success message (PASS).
Change-Id: Iafd583ee5529a8aef5439b9f1f6ce0185e4b1331
Reviewed-on: https://go-review.googlesource.com/9304
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also rename and update mkdoc.sh to mkalldocs.sh
Change-Id: Ief3673c22d45624e173fc65ee279cea324da03b5
Reviewed-on: https://go-review.googlesource.com/9226
Reviewed-by: Russ Cox <rsc@golang.org>
The motivation is that sysAlloc/Free() currently aren't safe to be
called without a valid G, because arm's xadd64() uses locks that require
a valid G.
The solution here was proposed by Dmitry Vyukov: use xadduintptr()
instead of xadd64(), until arm can support xadd64 on all of its
architectures (not a trivial task for arm).
Change-Id: I250252079357ea2e4360e1235958b1c22051498f
Reviewed-on: https://go-review.googlesource.com/9002
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
- main3.c tests main.main is exported when compiled for GOOS=android.
- wait longer for main2.c (it's slow on android/arm)
- rearranged test.bash
Fixes#10070.
Change-Id: I6e5a98d1c5fae776afa54ecb5da633b59b269316
Reviewed-on: https://go-review.googlesource.com/9296
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
This lets us avoid loading string constants via the GOT and (together with
http://golang.org/cl/9102) results in the fannkuch benchmark having very similar
register usage with -dynlink as without.
Change-Id: Ic3892b399074982b76773c3e547cfbba5dabb6f9
Reviewed-on: https://go-review.googlesource.com/9103
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Currently, when allocation reaches the GC trigger, the runtime uses
readyExecute to start the GC goroutine immediately rather than wait
for the scheduler to get around to the GC goroutine while the mutator
continues to grow the heap.
Now that the scheduler runs the most recently readied goroutine when a
goroutine yields its time slice, this rigmarole is no longer
necessary. The runtime can simply ready the GC goroutine and yield
from the readying goroutine.
Change-Id: I3b4ebadd2a72a923b1389f7598f82973dd5c8710
Reviewed-on: https://go-review.googlesource.com/9292
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Currently, the main GC goroutine sleeps on a note during concurrent
mark and the first background mark worker or assist to finish marking
use wakes up that note to let the main goroutine proceed into mark
termination. Unfortunately, the latency of this wakeup can be quite
high, since the GC goroutine will typically have lost its P while in
the futex sleep, meaning it will be placed on the global run queue and
will wait there until some P is kind enough to pick it up. This delay
gives the mutator more time to allocate and create floating garbage,
growing the heap unnecessarily. Worse, it's likely that background
marking has stopped at this point (unless GOMAXPROCS>4), so anything
that's allocated and published to the heap during this window will
have to be scanned during mark termination while the world is stopped.
This change replaces the note sleep/wakeup with a gopark/ready
scheme. This keeps the wakeup inside the Go scheduler and lets the
garbage collector take advantage of the new scheduler semantics that
run the ready()d goroutine immediately when the ready()ing goroutine
sleeps.
For the json benchmark from x/benchmarks with GOMAXPROCS=4, this
reduces the delay in waking up the GC goroutine and entering mark
termination once concurrent marking is done from ~100ms to typically
<100µs.
Change-Id: Ib11f8b581b8914f2d68e0094f121e49bac3bb384
Reviewed-on: https://go-review.googlesource.com/9291
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, we use a note sleep with a timeout in a loop in func gc to
periodically revise the GC control variables. Replace this with a
fully blocking note sleep and use a periodic timer to trigger the
revise instead. This is a step toward replacing the note sleep in func
gc.
Change-Id: I2d562f6b9b2e5f0c28e9a54227e2c0f8a2603f63
Reviewed-on: https://go-review.googlesource.com/9290
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Currently, when the runtime ready()s a G, it adds it to the end of the
current P's run queue and continues running. If there are many other
things in the run queue, this can result in a significant delay before
the ready()d G actually runs and can hurt fairness when other Gs in
the run queue are CPU hogs. For example, if there are three Gs sharing
a P, one of which is a CPU hog that never voluntarily gives up the P
and the other two of which are doing small amounts of work and
communicating back and forth on an unbuffered channel, the two
communicating Gs will get very little CPU time.
Change this so that when G1 ready()s G2 and then blocks, the scheduler
immediately hands off the remainder of G1's time slice to G2. In the
above example, the two communicating Gs will now act as a unit and
together get half of the CPU time, while the CPU hog gets the other
half of the CPU time.
This fixes the problem demonstrated by the ping-pong benchmark added
in the previous commit:
benchmark old ns/op new ns/op delta
BenchmarkPingPongHog 684287 825 -99.88%
On the x/benchmarks suite, this change improves the performance of
garbage by ~6% (for GOMAXPROCS=1 and 4), and json by 28% and 36% for
GOMAXPROCS=1 and 4. It has negligible effect on heap size.
This has no effect on the go1 benchmark suite since those benchmarks
are mostly single-threaded.
Change-Id: I858a08eaa78f702ea98a5fac99d28a4ac91d339f
Reviewed-on: https://go-review.googlesource.com/9289
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This benchmark demonstrates a current problem with the scheduler where
a set of frequently communicating goroutines get very little CPU time
in the presence of another goroutine that hogs that CPU, even if one
of those communicating goroutines is always runnable.
Currently it takes about 0.5 milliseconds to switch between
ping-ponging goroutines in the presence of a CPU hog:
BenchmarkPingPongHog 2000 684287 ns/op
Change-Id: I278848c84f778de32344921ae8a4a8056e4898b0
Reviewed-on: https://go-review.googlesource.com/9288
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
There are a variety of places where we check if a P's run queue is
empty. This test is about to get slightly more complicated, so factor
it out into a new function, runqempty. This function is inlinable, so
this has no effect on performance.
Change-Id: If4a0b01ffbd004937de90d8d686f6ded4aad2c6b
Reviewed-on: https://go-review.googlesource.com/9287
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We can expand the test cases as we discover problems.
This is some basic tests plus all the things I got wrong
in some recent work.
Change-Id: Id875fcfaf74eb087ae42b441fe47a34c5b8ccb39
Reviewed-on: https://go-review.googlesource.com/9158
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Explicitly specify that we represent polynomial in reversed notation
Fixes#8229
Change-Id: Idf094c01fd82f133cd0c1b50fa967d12c577bdb5
Reviewed-on: https://go-review.googlesource.com/9237
Reviewed-by: David Chase <drchase@google.com>
Some machines are so slow that even with the default timeoutScale,
they still timeout some tests. For example, currently some linux/arm
builders and the openbsd/arm builder are timing out the runtime
test and CL 8397 was proposed to skip some tests on openbsd/arm
to fix the build.
Instead of increasing timeoutScale or skipping tests, this CL
introduces an environment variable $GO_TEST_TIMEOUT_SCALE that
could be set to manually set a larger timeoutScale for those
machines/builders.
Fixes#10314.
Change-Id: I16c9a9eb980d6a63309e4cacd79eee2fe05769ee
Reviewed-on: https://go-review.googlesource.com/9223
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Forward signals to signal handlers installed before Go installs its own,
under certain circumstances. In particular, as iant@ suggests, signals are
forwarded iff:
(1) a non-SIG_DFL signal handler existed before Go, and
(2) signal is synchronous (i.e., one of SIGSEGV, SIGBUS, SIGFPE), and
(3a) signal occured on a non-Go thread, or
(3b) signal occurred on a Go thread but in CGo code.
Supported only on Linux, for now.
Change-Id: I403219ee47b26cf65da819fb86cf1ec04d3e25f5
Reviewed-on: https://go-review.googlesource.com/8712
Reviewed-by: Ian Lance Taylor <iant@golang.org>
They are vestiges of the c2go transition.
Change-Id: I22672e40373ef77d7a0bf69cfff8017e46353055
Reviewed-on: https://go-review.googlesource.com/9265
Reviewed-by: Minux Ma <minux@golang.org>
This addresses iant's comments from CL 9164.
Change-Id: I7b5b282f61b11aab587402c2d302697e76666376
Reviewed-on: https://go-review.googlesource.com/9222
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, it's possible for the next_gc calculation to underflow.
Since next_gc is unsigned, this wraps around and effectively disables
GC for the rest of the program's execution. Besides being obviously
wrong, this is causing test failures on 32-bit because some tests are
running out of heap.
This underflow happens for two reasons, both having to do with how we
estimate the reachable heap size at the end of the GC cycle.
One reason is that this calculation depends on the value of heap_live
at the beginning of the GC cycle, but we currently only record that
value during a concurrent GC and not during a forced STW GC. Fix this
by moving the recorded value from gcController to work and recording
it on a common code path.
The other reason is that we use the amount of allocation during the GC
cycle as an approximation of the amount of floating garbage and
subtract it from the marked heap to estimate the reachable heap.
However, since this is only an approximation, it's possible for the
amount of allocation during the cycle to be *larger* than the marked
heap size (since the runtime allocates white and it's possible for
these allocations to never be made reachable from the heap). Currently
this causes wrap-around in our estimate of the reachable heap size,
which in turn causes wrap-around in next_gc. Fix this by bottoming out
the reachable heap estimate at 0, in which case we just fall back to
triggering GC at heapminimum (which is okay since this only happens on
small heaps).
Fixes#10555, fixes#10556, and fixes#10559.
Change-Id: Iad07b529c03772356fede2ae557732f13ebfdb63
Reviewed-on: https://go-review.googlesource.com/9286
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
To achieve a 2% improvement in the garbage benchmark this CL removes
an unneeded assert and avoids one hbits.next() call per object
being scanned.
Change-Id: Ibd542d01e9c23eace42228886f9edc488354df0d
Reviewed-on: https://go-review.googlesource.com/9244
Reviewed-by: Austin Clements <austin@google.com>
newosproc0 does not work on android/arm.
See issue #10548.
Change-Id: Ieaf6f5d0b77cddf5bf0b6c89fd12b1c1b8723f9b
Reviewed-on: https://go-review.googlesource.com/9293
Reviewed-by: David Crawshaw <crawshaw@golang.org>
github.com/kr/goven says it's deprecated and anyway
it would be preferable to point users to a standard Go tool.
Change-Id: Iac4a0d13233604a36538748d498f5770b2afce19
Reviewed-on: https://go-review.googlesource.com/8969
Reviewed-by: Minux Ma <minux@golang.org>
If the machine's network configuration files (resolv.conf,
nsswitch.conf) don't have any unsupported options, prefer Go's DNS
resolver, which doesn't have the cgo & thread over.
It means users can have more than 500 DNS requests outstanding (our
current limit for cgo lookups) and not have one blocked thread per
outstanding request.
Discussed in thread https://groups.google.com/d/msg/golang-dev/2ZUi792oztM/Q0rg_DkF5HMJ
Change-Id: I3f685d70aff6b47bec30b63e9fba674b20507f95
Reviewed-on: https://go-review.googlesource.com/8945
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
They are vestiges of the c2go translation.
Change-Id: I9a10536f5986b751a35cc7d84b5ba69ae0c2ede7
Reviewed-on: https://go-review.googlesource.com/9262
Reviewed-by: Minux Ma <minux@golang.org>
There is an assumption that the function executed in child thread
created by runtime.close should not return. And different systems
enforce that differently: some exit that thread, some exit the
whole process.
The test TestNewOSProc0 introduced in CL 9161 breaks that assumption,
so we need to adjust the code to only exit the thread should the
called function return.
Change-Id: Id631cb2f02ec6fbd765508377a79f3f96c6a2ed6
Reviewed-on: https://go-review.googlesource.com/9246
Reviewed-by: Dave Cheney <dave@cheney.net>
It was only visible when you run godoc with explicit GOOS=windows,
which is less useful for people developing portable application on
non-windows platforms.
Also added a note that log/syslog is not supported on NaCl.
Change-Id: I81650445fb2a5ee161da7e0608c3d3547d5ac2a6
Reviewed-on: https://go-review.googlesource.com/9245
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The constants in cmd/internal/goobj had gone stale (we had three copies of
these constants, working on reducing that was what got me to noticing this).
Some of the changes to link.hello.darwin.amd64 are the change from absolute
to %rip-relative addressing, a change which happened quite a while ago...
Depends on http://golang.org/cl/9113.
Fixes#10501.
Change-Id: Iaa1511f458a32228c2df2ccd0076bb9ae212a035
Reviewed-on: https://go-review.googlesource.com/9105
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, we set the heap goal for the next GC cycle using the size
of the marked heap at the end of the current cycle. This can lead to a
bad feedback loop if the mutator is rapidly allocating and releasing
pointers that can significantly bloat heap size.
If the GC were STW, the marked heap size would be exactly the
reachable heap size (call it stwLive). However, in concurrent GC,
marked=stwLive+floatLive, where floatLive is the amount of "floating
garbage": objects that were reachable at some point during the cycle
and were marked, but which are no longer reachable by the end of the
cycle. If the GC cycle is short, then the mutator doesn't have much
time to create floating garbage, so marked≈stwLive. However, if the GC
cycle is long and the mutator is allocating and creating floating
garbage very rapidly, then it's possible that marked≫stwLive. Since
the runtime currently sets the heap goal based on marked, this will
cause it to set a high heap goal. This means that 1) the next GC cycle
will take longer because of the larger heap and 2) the assist ratio
will be low because of the large distance between the trigger and the
goal. The combination of these lets the mutator produce even more
floating garbage in the next cycle, which further exacerbates the
problem.
For example, on the garbage benchmark with GOMAXPROCS=1, this causes
the heap to grow to ~500MB and the garbage collector to retain upwards
of ~300MB of heap, while the true reachable heap size is ~32MB. This,
in turn, causes the GC cycle to take upwards of ~3 seconds.
Fix this bad feedback loop by estimating the true reachable heap size
(stwLive) and using this rather than the marked heap size
(stwLive+floatLive) as the basis for the GC trigger and heap goal.
This breaks the bad feedback loop and causes the mutator to assist
more, which decreases the rate at which it can create floating
garbage. On the same garbage benchmark, this reduces the maximum heap
size to ~73MB, the retained heap to ~40MB, and the duration of the GC
cycle to ~200ms.
Change-Id: I7712244c94240743b266f9eb720c03802799cdd1
Reviewed-on: https://go-review.googlesource.com/9177
Reviewed-by: Rick Hudson <rlh@golang.org>
Change-Id: I429402dd91243cd9415b054ee17bfebccc68ed57
Reviewed-on: https://go-review.googlesource.com/9197
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
This may or may not be useful to the end user, but it's incredibly
useful for us to understand the behavior of the pacer. Currently this
is fairly easy (though not trivial) to derive from the other heap
stats we print, but we're about to change how we compute the goal,
which will make it much harder to derive.
Change-Id: I796ef233d470c01f606bd9929820c01ece1f585a
Reviewed-on: https://go-review.googlesource.com/9176
Reviewed-by: Rick Hudson <rlh@golang.org>
The trigger controller computes GC CPU utilization by dividing by the
wall-clock time that's passed since concurrent mark began. Since this
delta is nanoseconds it's borderline impossible for it to be zero, but
if it is zero we'll currently divide by zero. Be robust to this
possibility by ignoring the utilization in the error term if no time
has elapsed.
Change-Id: I93dfc9e84735682af3e637f6538d1e7602634f09
Reviewed-on: https://go-review.googlesource.com/9175
Reviewed-by: Rick Hudson <rlh@golang.org>
To make the gcprog for global data containing variables of types defined in other shared
libraries, we need to know a lot about those types. So read the value of any symbol with
a name starting with "type.". If a type uses a mask, the name of the symbol defining the
mask unfortunately cannot be predicted from the type name so I have to keep track of the
addresses of every such symbol and associate them with the type symbols after the fact.
I'm not very happy about this change, but something like this is needed and this is as
pleasant as I know how to make it.
Change-Id: I408d831b08b3b31e0610688c41367b23998e975c
Reviewed-on: https://go-review.googlesource.com/8334
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
There were 10 implementations of the trivial bool2int function, 9 of which
were the only thing in their file. Remove all of them in favor of one in
cmd/internal/obj.
Change-Id: I9c51d30716239df51186860b9842a5e9b27264d3
Reviewed-on: https://go-review.googlesource.com/9230
Reviewed-by: Ian Lance Taylor <iant@golang.org>
since the "precision" parameter means constant arithmetic is not
necessarily exact.
As requested by gri, within go/types, the local import name 'exact'
has been kept, to reduce the diff with the x/tools branch. This may
be changed later.
Since the go/types.bash script was already obsolete, I added a comment
to this effect.
Tested with all.bash.
Change-Id: I45153688d9d8afa8384fb15229b0124c686059b4
Reviewed-on: https://go-review.googlesource.com/9242
Reviewed-by: Rob Pike <r@golang.org>
