Commit Graph

169 Commits

Author SHA1 Message Date
Keith Randall 2278a51fa0 sync/atomic: use consistent first-store-in-progress marker
We need to use the same marker everywhere. My CL to rename the
marker (CL 241661) and the CL to add more uses of the marker
under the old name (CL 241678) weren't coordinated with each other.

Fixes #52612

Change-Id: I97023c0769e518491924ef457fe03bf64a2cefa6
Reviewed-on: https://go-review.googlesource.com/c/go/+/403094
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
2022-04-29 20:42:52 +00:00
Michael Pratt 29bbca5c2c runtime: differentiate "user" and "system" throws
"User" throws are throws due to some invariant broken by the application.
"System" throws are due to some invariant broken by the runtime,
environment, etc (i.e., not the fault of the application).

This CL sends "user" throws through the new fatal. Currently this
function is identical to throw, but with a different name to clearly
differentiate the throw type in the stack trace, and hopefully be a bit
more clear to users what it means.

This CL changes a few categories of throw to fatal:

1. Concurrent map read/write.
2. Deadlock detection.
3. Unlock of unlocked sync.Mutex.
4. Inconsistent results from syscall.AllThreadsSyscall.

"Thread exhaustion" and "out of memory" (usually address space full)
throws are additional throws that are arguably the fault of user code,
but I've left off for now because there is no specific invariant that
they have broken to get into these states.

For #51485

Change-Id: I713276a6c290fd34a6563e6e9ef378669d74ae32
Reviewed-on: https://go-review.googlesource.com/c/go/+/390420
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
2022-04-28 16:50:31 +00:00
Russ Cox 19309779ac all: gofmt main repo
[This CL is part of a sequence implementing the proposal #51082.
The design doc is at https://go.dev/s/godocfmt-design.]

Run the updated gofmt, which reformats doc comments,
on the main repository. Vendored files are excluded.

For #51082.

Change-Id: I7332f099b60f716295fb34719c98c04eb1a85407
Reviewed-on: https://go-review.googlesource.com/c/go/+/384268
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2022-04-11 16:34:30 +00:00
Russ Cox 9839668b56 all: separate doc comment from //go: directives
A future change to gofmt will rewrite

	// Doc comment.
	//go:foo

to

	// Doc comment.
	//
	//go:foo

Apply that change preemptively to all comments (not necessarily just doc comments).

For #51082.

Change-Id: Iffe0285418d1e79d34526af3520b415a12203ca9
Reviewed-on: https://go-review.googlesource.com/c/go/+/384260
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-04-05 17:54:15 +00:00
Russ Cox 690ac4071f all: remove trailing blank doc comment lines
A future change to gofmt will rewrite

	// Doc comment.
	//
	func f()

to

	// Doc comment.
	func f()

Apply that change preemptively to all doc comments.

For #51082.

Change-Id: I4023e16cfb0729b64a8590f071cd92f17343081d
Reviewed-on: https://go-review.googlesource.com/c/go/+/384259
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
2022-04-01 18:18:07 +00:00
Russ Cox 2580d0e08d all: gofmt -w -r 'interface{} -> any' src
And then revert the bootstrap cmd directories and certain testdata.
And adjust tests as needed.

Not reverting the changes in std that are bootstrapped,
because some of those changes would appear in API docs,
and we want to use any consistently.
Instead, rewrite 'any' to 'interface{}' in cmd/dist for those directories
when preparing the bootstrap copy.

A few files changed as a result of running gofmt -w
not because of interface{} -> any but because they
hadn't been updated for the new //go:build lines.

Fixes #49884.

Change-Id: Ie8045cba995f65bd79c694ec77a1b3d1fe01bb09
Reviewed-on: https://go-review.googlesource.com/c/go/+/368254
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
2021-12-13 18:45:54 +00:00
Ian Lance Taylor fdd67930a0 sync: in TryLock try to acquire mutex even if state is not 0
For #45435

Change-Id: I728accd9a53c1826243f52aa04dc2a0a1dfdaadf
Reviewed-on: https://go-review.googlesource.com/c/go/+/363672
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2021-11-16 05:58:03 +00:00
Changkun Ou d5a5a13ad9 sync: clarify the validity to call Map methods inside Range
This change clarifies that calling all Map methods inside the callback
of Range is allowed. For further assurance, a nested range call test
is also added.

Fixes #46399

Change-Id: I0a766a5c1470e6b573ec35df1ccd62b2e46f1561
Reviewed-on: https://go-review.googlesource.com/c/go/+/337389
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Ian Lance Taylor <iant@golang.org>
2021-11-11 04:41:56 +00:00
Tobias Klauser f19e400180 all: remove more leftover // +build lines
CL 344955 and CL 359476 removed almost all // +build lines, but leaving
some assembly files and generating scripts. Also, some files were added
with // +build lines after CL 359476 was merged. Remove these or rename
files where more appropriate.

For #41184

Change-Id: I7eb85a498ed9788b42a636e775f261d755504ffa
Reviewed-on: https://go-review.googlesource.com/c/go/+/361480
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2021-11-06 10:24:44 +00:00
Michael Anthony Knyszek 256a8fc6ef sync/atomic: disable GC during TestHammerStoreLoad
TestHammerStoreLoad involves a stress test of StorePointer, which has a
write barrier. The "pointer" that is being written is not a real value,
which is generally fine (though not *really* safe) on 64-bit systems
because they never point to an actual object.

On 32-bit systems, however, this is much more likely. Because I can't
figure out how to rewrite the test such that it still is testing the
same conditions but is also using real pointers, just disable the GC
during the test, and make sure there isn't one currently in progress.

Fixes #49362.

Change-Id: If81883fedf06568132e6484f40c820aa69027a9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/361455
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
2021-11-04 23:35:26 +00:00
Ruslan Andreev 5f1bcd1bc2 sync: add PoolStarvation benchmark
This benchmark simulates object starvation in order to force Ps to steal
objects from other Ps. Extracted from CL 314229.

Change-Id: Iee31df355ba04d80fbd91c4414e397a375e6d6d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/360256
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Trust: Cherry Mui <cherryyz@google.com>
2021-11-01 19:42:30 +00:00
Russ Cox 645d07819b sync: add Mutex.TryLock, RWMutex.TryLock, RWMutex.TryRLock
Use of these functions is almost (but not) always a bad idea.

Very rarely they are necessary, and third-party implementations
(using a mutex and an atomic word, say) cannot integrate as well
with the race detector as implmentations in package sync itself.

Fixes #45435.

Change-Id: I0128ca48ef5e0a3b09c913f0f3a7ee5c56388000
Reviewed-on: https://go-review.googlesource.com/c/go/+/319769
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2021-10-29 17:13:13 +00:00
Russ Cox f229e7031a all: go fix -fix=buildtag std cmd (except for bootstrap deps, vendor)
When these packages are released as part of Go 1.18,
Go 1.16 will no longer be supported, so we can remove
the +build tags in these files.

Ran go fix -fix=buildtag std cmd and then reverted the bootstrapDirs
as defined in src/cmd/dist/buildtool.go, which need to continue
to build with Go 1.4 for now.

Also reverted src/vendor and src/cmd/vendor, which will need
to be updated in their own repos first.

Manual changes in runtime/pprof/mprof_test.go to adjust line numbers.

For #41184.

Change-Id: Ic0f93f7091295b6abc76ed5cd6e6746e1280861e
Reviewed-on: https://go-review.googlesource.com/c/go/+/344955
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2021-10-28 18:17:57 +00:00
Keith Randall 3a0cd11214 sync/atomic: use a better first-store-in-progress marker
Unlike what the comment says, the GC can see this pointer.
Might as well make it a real pointer, even though ^uintptr(0)
isn't currently causing problems.

Removed the comment about GC not seeing the pointer.

Change-Id: I04bc1fd4848698bec6afb79bd5fda671dfc9a073
Reviewed-on: https://go-review.googlesource.com/c/go/+/241661
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Colin Arnott <colin@urandom.co.uk>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Keith Randall <khr@golang.org>
2021-10-26 20:41:32 +00:00
Carlo Alberto Ferraris ad7db1f90f sync: avoid a dynamic check in WaitGroup on 64-bit architectures
uint64 is guaranteed by the compiler to be aligned on 64-bit archs.
By using uint64+uint32 instead of [3]uint32 we can make use of the
guaranteed alignment to avoid the run-time alignment check.

On linux/amd64:

name                     old time/op    new time/op    delta
WaitGroupUncontended-4     8.84ns ± 3%    7.62ns ± 4%  -13.72%  (p=0.000 n=17+18)
WaitGroupAddDone-4         66.8ns ± 3%    45.9ns ± 2%  -31.31%  (p=0.000 n=20+18)
WaitGroupAddDoneWork-4     79.2ns ± 1%    56.6ns ± 1%  -28.54%  (p=0.000 n=17+20)
WaitGroupWait-4            2.83ns ± 2%    2.58ns ± 2%   -9.05%  (p=0.000 n=18+20)
WaitGroupWaitWork-4        16.8ns ± 6%    16.5ns ± 6%     ~     (p=0.072 n=20+18)
WaitGroupActuallyWait-4     263ns ± 2%     261ns ± 5%     ~     (p=0.063 n=18+20)

Change-Id: I314340f2ed8a47d8b9c15f8a3b07e41f252f4831
Reviewed-on: https://go-review.googlesource.com/c/go/+/189837
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-10-19 18:21:38 +00:00
Damien Neil 011fd00245 sync: remove TestWaitGroupMisuse2 and TestWaitGroupMisuse3
These tests are inherently nondeterministic: They exercise a racy
code path for up to one million iterations, and require that an
error occur at least once.

TestWaitGroupMisuse2 in particular is an ongoing source of trybot
flakiness.

Fixes #38163.

Change-Id: Ibbbda2c998c915333487ad262d3df6829de01c2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/340249
Trust: Damien Neil <dneil@google.com>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2021-10-14 17:38:39 +00:00
Sean Liao eba91e83b0 sync: use example.com for url in ExampleWaitGroup
Fixes #48886

Change-Id: I1093ae0ba30dab5a73d4d6bcfd083564d13877a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/354830
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Meng Zhuo <mzh@golangcn.org>
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
2021-10-09 14:53:12 +00:00
Meng Zhuo ecb2f231fa runtime,sync: using fastrandn instead of modulo reduction
fastrandn is ~50% faster than fastrand() % n.
`ack -v 'fastrand\(\)\s?\%'` finds all modulo on fastrand()

name              old time/op  new time/op  delta
Fastrandn/2       2.86ns ± 0%  1.59ns ± 0%  -44.35%  (p=0.000 n=9+10)
Fastrandn/3       2.87ns ± 1%  1.59ns ± 0%  -44.41%  (p=0.000 n=10+9)
Fastrandn/4       2.87ns ± 1%  1.58ns ± 1%  -45.10%  (p=0.000 n=10+10)
Fastrandn/5       2.86ns ± 1%  1.58ns ± 1%  -44.84%  (p=0.000 n=10+10)

Change-Id: Ic91f5ca9b9e3b65127bc34792b62fd64fbd13b5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/353269
Trust: Meng Zhuo <mzh@golangcn.org>
Run-TryBot: Meng Zhuo <mzh@golangcn.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-10-07 14:01:52 +00:00
Jeff Wentworth 0a0a160d4d sync/atomic: fix documentation for CompareAndSwap
Fixes #47699

The documentation for CompareAndSwap atomic/value incorrectly labelled the function as CompareAndSwapPointer. This PR fixes that.

Change-Id: I6db08fdfe166570b775248fd24550f5d28e3434e
GitHub-Last-Rev: 41f7870792
GitHub-Pull-Request: golang/go#47700
Reviewed-on: https://go-review.googlesource.com/c/go/+/342210
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Trust: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Go Bot <gobot@golang.org>
2021-08-14 16:56:14 +00:00
Tobias Klauser 2c76a6f7f8 all: add //go:build lines to assembly files
Don't add them to files in vendor and cmd/vendor though. These will be
pulled in by updating the respective dependencies.

For #41184

Change-Id: Icc57458c9b3033c347124323f33084c85b224c70
Reviewed-on: https://go-review.googlesource.com/c/go/+/319389
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2021-05-13 09:12:17 +00:00
Colin Arnott 2422c5eae5 sync/atomic: add (*Value).Swap and (*Value).CompareAndSwap
The functions SwapPointer and CompareAndSwapPointer can be used to
interact with unsafe.Pointer, however generally it is prefered to work
with Value, due to its safer interface. As such, they have been added
along with glue logic to maintain invariants Value guarantees.

To meet these guarantees, the current implementation duplicates much of
the Store function. Some of this is due to inexperience with concurrency
and desire for correctness, but the lack of generic programming
functionality does not help.

Fixes #39351

Change-Id: I1aa394b1e70944736ac1e19de49fe861e1e46fba
Reviewed-on: https://go-review.googlesource.com/c/go/+/241678
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-05-04 00:15:27 +00:00
Bryan C. Mills 0d1280c685 Revert "sync: improve sync.Pool object stealing"
This reverts CL 303949.

Reason for revert: broke linux-arm-aws TryBots.

Change-Id: Ib44949df70520cdabff857846be0d2221403d2f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/313630
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-04-26 18:54:39 +00:00
Ruslan Andreev d5d24dbe41 sync: improve sync.Pool object stealing
This CL provide abilty to randomly select P to steal object from its
shared queue. In order to provide such ability randomOrder structure
was copied from runtime/proc.go.
It should reduce contention in firsts Ps and improve balance of object
stealing across all Ps. Also, the patch provides new benchmark
PoolStarvation which force Ps to steal objects.
Benchmarks:
name                old time/op     new time/op     delta
Pool-8                 2.16ns ±14%     2.14ns ±16%    ~     (p=0.425 n=10+10)
PoolOverflow-8          489ns ± 0%      489ns ± 0%    ~     (p=0.719 n=9+10)
PoolStarvation-8       7.00µs ± 4%     6.59µs ± 2%  -5.86%  (p=0.000 n=10+10)
PoolSTW-8              15.1µs ± 1%     15.2µs ± 1%  +0.99%  (p=0.001 n=10+10)
PoolExpensiveNew-8     1.25ms ±10%     1.31ms ± 9%    ~     (p=0.143 n=10+10)
[Geo mean]             2.68µs          2.68µs       -0.28%

name                old p50-ns/STW  new p50-ns/STW  delta
PoolSTW-8               15.0k ± 1%      15.1k ± 1%  +0.92%  (p=0.000 n=10+10)

name                old p95-ns/STW  new p95-ns/STW  delta
PoolSTW-8               16.2k ± 3%      16.4k ± 2%    ~     (p=0.143 n=10+10)

name                old GCs/op      new GCs/op      delta
PoolExpensiveNew-8       0.29 ± 2%       0.30 ± 1%  +2.84%  (p=0.000 n=8+10)

name                old New/op      new New/op      delta
PoolExpensiveNew-8       8.07 ±11%       8.49 ±10%    ~     (p=0.123 n=10+10)

Change-Id: I3ca1d0bf1f358b1148c58e64740fb2d5bfc0bc02
Reviewed-on: https://go-review.googlesource.com/c/go/+/303949
Reviewed-by: David Chase <drchase@google.com>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
2021-04-26 17:13:36 +00:00
panchenglong01 1749f3915e sync: update misleading comment in map.go about entry type
As discussed in: https://github.com/golang/go/issues/45429,  about entry
type comments, it is possible for p == nil when m.dirty != nil, so
update the commemt about it.

Fixes #45429

Change-Id: I7ef96ee5b6948df9ac736481d177a59ab66d7d4d
GitHub-Last-Rev: 202c598a0a
GitHub-Pull-Request: golang/go#45443
Reviewed-on: https://go-review.googlesource.com/c/go/+/308292
Reviewed-by: Changkun Ou <euryugasaki@gmail.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Trust: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-04-08 14:08:29 +00:00
Russ Cox d4b2638234 all: go fmt std cmd (but revert vendor)
Make all our package sources use Go 1.17 gofmt format
(adding //go:build lines).

Part of //go:build change (#41184).
See https://golang.org/design/draft-gobuild

Change-Id: Ia0534360e4957e58cd9a18429c39d0e32a6addb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/294430
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2021-02-20 03:54:50 +00:00
Martin Möhrmann d902791b50 sync: use 386 instead of x86-32 to refer to the 32 bit x86 architecture
This aligns the naming with GOARCH using 386 as a build target for
this architecture and makes it more easily found when searching
for documentation related to the build target.

Change-Id: I393bb89dd2f71e568124107b13e1b288fbd0c76a
Reviewed-on: https://go-review.googlesource.com/c/go/+/271988
Trust: Martin Möhrmann <moehrmann@google.com>
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-11-23 05:57:35 +00:00
Michael Pratt b4f3d52f6a sync: document RWMutex race semantics
RWMutex provides explicit acquire/release synchronization events to the
race detector to model the mutex. It disables sync events within the
methods to avoid e.g., the atomics from adding false synchronization
events, which could cause false negatives in the race detector.

Change-Id: I5126ce2efaab151811ac264864aab1fa025a4aaf
Reviewed-on: https://go-review.googlesource.com/c/go/+/270865
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Trust: Michael Pratt <mpratt@google.com>
2020-11-18 20:12:03 +00:00
Austin Clements c305e49e96 cmd/go,cmd/compile,sync: remove special import case in cmd/go
CL 253748 introduced a special case in cmd/go to allow sync to import
runtime/internal/atomic. Besides introducing unnecessary complexity
into cmd/go, this breaks other packages (like gopls) that understand
how imports work, but don't understand this special case.

Fix this by using the more standard linkname-based approach to pull
the necessary functions from runtime/internal/atomic into sync. Since
these are compiler intrinsics, we also have to tell the compiler that
the linknamed symbols are intrinsics to get this optimization in sync.

Fixes #42196.

Change-Id: I1f91498c255c91583950886a89c3c9adc39a32f0
Reviewed-on: https://go-review.googlesource.com/c/go/+/265124
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Paul Murphy <murp@ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
2020-10-26 20:12:53 +00:00
Dmitri Shuralyov f8376a55b0 sync: document that Once must not be copied
Fixes #42160.

Change-Id: I9bf8b6f0bf1eccd3ab32cbd94c812f768746d291
Reviewed-on: https://go-review.googlesource.com/c/go/+/264557
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2020-10-23 19:57:55 +00:00
Paul E. Murphy 15ead857db cmd/compiler,cmd/go,sync: add internal {LoadAcq,StoreRel}64 on ppc64
Add an internal atomic intrinsic for load with acquire semantics
(extending LoadAcq to 64b) and add LoadAcquintptr for internal
use within the sync package.  For other arches, this remaps to the
appropriate atomic.Load{,64} intrinsic which should not alter code
generation.

Similarly, add StoreRel{uintptr,64} for consistency, and inline.

Finally, add an exception to allow sync to directly use the
runtime/internal/atomic package which avoids more convoluted
workarounds (contributed by Lynn Boger).

In an extreme example, sync.(*Pool).pin consumes 20% of wall time
during fmt tests.  This is reduced to 5% on ppc64le/power9.

From the fmt benchmarks on ppc64le:

name                           old time/op  new time/op  delta
SprintfPadding                  468ns ± 0%   451ns ± 0%   -3.63%
SprintfEmpty                   73.3ns ± 0%  51.9ns ± 0%  -29.20%
SprintfString                   135ns ± 0%   122ns ± 0%   -9.63%
SprintfTruncateString           232ns ± 0%   214ns ± 0%   -7.76%
SprintfTruncateBytes            216ns ± 0%   202ns ± 0%   -6.48%
SprintfSlowParsingPath          162ns ± 0%   142ns ± 0%  -12.35%
SprintfQuoteString             1.00µs ± 0%  0.99µs ± 0%   -1.39%
SprintfInt                      117ns ± 0%   104ns ± 0%  -11.11%
SprintfIntInt                   190ns ± 0%   175ns ± 0%   -7.89%
SprintfPrefixedInt              232ns ± 0%   212ns ± 0%   -8.62%
SprintfFloat                    270ns ± 0%   255ns ± 0%   -5.56%
SprintfComplex                 1.01µs ± 0%  0.99µs ± 0%   -1.68%
SprintfBoolean                  127ns ± 0%   111ns ± 0%  -12.60%
SprintfHexString                220ns ± 0%   198ns ± 0%  -10.00%
SprintfHexBytes                 261ns ± 0%   252ns ± 0%   -3.45%
SprintfBytes                    600ns ± 0%   590ns ± 0%   -1.67%
SprintfStringer                 684ns ± 0%   658ns ± 0%   -3.80%
SprintfStructure               2.57µs ± 0%  2.57µs ± 0%   -0.12%
ManyArgs                        669ns ± 0%   646ns ± 0%   -3.44%
FprintInt                       140ns ± 0%   136ns ± 0%   -2.86%
FprintfBytes                    184ns ± 0%   181ns ± 0%   -1.63%
FprintIntNoAlloc                140ns ± 0%   136ns ± 0%   -2.86%
ScanInts                        929µs ± 0%   921µs ± 0%   -0.79%
ScanRecursiveInt                122ms ± 0%   121ms ± 0%   -0.11%
ScanRecursiveIntReaderWrapper   122ms ± 0%   122ms ± 0%   -0.18%

Change-Id: I4d66780261b57b06ef600229e475462e7313f0d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/253748
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Go Bot <gobot@golang.org>
2020-10-21 14:34:44 +00:00
Austin Clements 83317d9e3c runtime/internal/atomic: panic nicely on unaligned 64-bit atomics
On 386 and arm, unaligned 64-bit atomics aren't safe, so we check for
this and panic. Currently, we panic by dereferencing nil, which may be
expedient but is pretty user-hostile since it gives no hint of what
the actual problem was.

This CL replaces this with an actual panic. The only subtlety here is
now the atomic assembly implementations are calling back into Go, so
they have to play nicely with stack maps and stack scanning. On 386,
this just requires declaring NO_LOCAL_POINTERS. On arm, this is
somewhat more complicated: first, we have to move the alignment check
into the functions that have Go signatures. Then we have to support
both the tail call from these functions to the underlying
implementation (which requires that they have no frame) and the call
into Go to panic (which requires that they have a frame). We resolve
this by forcing them to have no frame and setting up the frame
manually just before the panic call.

Change-Id: I19f1e860045df64088013db37a18acea47342c69
Reviewed-on: https://go-review.googlesource.com/c/go/+/262778
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
2020-10-16 17:31:17 +00:00
ZhangYunHao a3bc52b786 sync: fix typo in pooldequeue
.

Change-Id: I26fa26d67d01bcd583a1efaaf9a38398cbf793f7
GitHub-Last-Rev: ded020d02c
GitHub-Pull-Request: golang/go#41932
Reviewed-on: https://go-review.googlesource.com/c/go/+/261477
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
2020-10-14 13:38:41 +00:00
Changkun Ou 94953d3e59 sync: delete dirty keys inside Map.LoadAndDelete
Fixes #40999

Change-Id: Ie32427e5cb5ed512b976b554850f50be156ce9f2
Reviewed-on: https://go-review.googlesource.com/c/go/+/250197
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2020-08-24 20:05:41 +00:00
Tobias Klauser dc12d5b0f5 all: add empty line between copyright header and package clause
Makes sure the copyright notice is not interpreted as the package level
godoc.

Change-Id: I2afce7c9d620f19d51ec1438b1d0db1774b57146
Reviewed-on: https://go-review.googlesource.com/c/go/+/248760
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
2020-08-17 09:45:44 +00:00
Gaurav Singh 5a18e0b58c sync: fix goroutine leak for when TestMutexFairness times out
If the timeout triggers before writing to the done channel, the
goroutine will be blocked waiting for a corresponding read that’s
no longer existent, thus a goroutine leak. This change fixes that by
using a buffered channel instead.

Change-Id: I9cf4067a58bc5a729ab31e4426edd78bd359e8e0
GitHub-Last-Rev: a7d811a7be
GitHub-Pull-Request: golang/go#40236
Reviewed-on: https://go-review.googlesource.com/c/go/+/242902
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-08-14 23:04:16 +00:00
Ian Lance Taylor 9591515f51 runtime, sync: add copyright headers to new files
For #38029

Change-Id: I71de2b66c1de617d32c46d4f2c1866f9ff1756ec
Reviewed-on: https://go-review.googlesource.com/c/go/+/244631
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-07-25 03:26:17 +00:00
BurtonQin 4874835232 net/textproto, sync: unlock mutexes appropriately before panics
Ensure mutexes are unlocked right before panics, where defers aren’t easily usable.

Change-Id: I67c9870e7a626f590a8de8df6c8341c5483918dc
GitHub-Last-Rev: bb8ffe538b
GitHub-Pull-Request: golang/go#37143
Reviewed-on: https://go-review.googlesource.com/c/go/+/218717
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-04-08 16:19:51 +00:00
Dan Scales 0a820007e7 runtime: static lock ranking for the runtime (enabled by GOEXPERIMENT)
I took some of the infrastructure from Austin's lock logging CR
https://go-review.googlesource.com/c/go/+/192704 (with deadlock
detection from the logs), and developed a setup to give static lock
ranking for runtime locks.

Static lock ranking establishes a documented total ordering among locks,
and then reports an error if the total order is violated. This can
happen if a deadlock happens (by acquiring a sequence of locks in
different orders), or if just one side of a possible deadlock happens.
Lock ordering deadlocks cannot happen as long as the lock ordering is
followed.

Along the way, I found a deadlock involving the new timer code, which Ian fixed
via https://go-review.googlesource.com/c/go/+/207348, as well as two other
potential deadlocks.

See the constants at the top of runtime/lockrank.go to show the static
lock ranking that I ended up with, along with some comments. This is
great documentation of the current intended lock ordering when acquiring
multiple locks in the runtime.

I also added an array lockPartialOrder[] which shows and enforces the
current partial ordering among locks (which is embedded within the total
ordering). This is more specific about the dependencies among locks.

I don't try to check the ranking within a lock class with multiple locks
that can be acquired at the same time (i.e. check the ranking when
multiple hchan locks are acquired).

Currently, I am doing a lockInit() call to set the lock rank of most
locks. Any lock that is not otherwise initialized is assumed to be a
leaf lock (a very high rank lock), so that eliminates the need to do
anything for a bunch of locks (including all architecture-dependent
locks). For two locks, root.lock and notifyList.lock (only in the
runtime/sema.go file), it is not as easy to do lock initialization, so
instead, I am passing the lock rank with the lock calls.

For Windows compilation, I needed to increase the StackGuard size from
896 to 928 because of the new lock-rank checking functions.

Checking of the static lock ranking is enabled by setting
GOEXPERIMENT=staticlockranking before doing a run.

To make sure that the static lock ranking code has no overhead in memory
or CPU when not enabled by GOEXPERIMENT, I changed 'go build/install' so
that it defines a build tag (with the same name) whenever any experiment
has been baked into the toolchain (by checking Expstring()). This allows
me to avoid increasing the size of the 'mutex' type when static lock
ranking is not enabled.

Fixes #38029

Change-Id: I154217ff307c47051f8dae9c2a03b53081acd83a
Reviewed-on: https://go-review.googlesource.com/c/go/+/207619
Reviewed-by: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-04-07 21:51:03 +00:00
Keith Randall 95773ab9b0 sync/atomic: fix TestSwapPointer test
It plays way too loose with unsafe.Pointer rules.
It runs afoul of the checkptr rules, so some race detector builds
were failing.

Fixes #38210

Change-Id: I5e1c78201d06295524fdedb3fe5b49d61446f443
Reviewed-on: https://go-review.googlesource.com/c/go/+/226880
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2020-04-02 03:47:13 +00:00
Daniel Martí a4c48d61f5 sync/atomic: remove panic64
The func has been unused since https://golang.org/cl/93637 in 2018.

Change-Id: I1cab6f265aa5058ac080fd7c7cbf0fe85370f073
Reviewed-on: https://go-review.googlesource.com/c/go/+/224077
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
2020-03-19 19:46:54 +00:00
Ziheng Liu 42f8199290 all: fix incorrect channel and API usage in some unit tests
This CL changes some unit test functions, making sure that these tests (and goroutines spawned during test) won't block.
Since they are just test functions, I use one CL to fix them all. I hope this won't cause trouble to reviewers and can save time for us.
There are three main categories of incorrect logic fixed by this CL:
1. Use testing.Fatal()/Fatalf() in spawned goroutines, which is forbidden by Go's document.
2. Channels are used in such a way that, when errors or timeout happen, the test will be blocked and never return.
3. Channels are used in such a way that, when errors or timeout happen, the test can return but some spawned goroutines will be leaked, occupying resource until all other tests return and the process is killed.

Change-Id: I3df931ec380794a0cf1404e632c1dd57c65d63e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/219380
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-02-27 19:04:17 +00:00
Changkun Ou 2e8dbae85c sync: add new Map method LoadAndDelete
This CL implements a LoadAndDelete method in sync.Map. Benchmark:

name                                              time/op
LoadAndDeleteBalanced/*sync_test.RWMutexMap-12    98.8ns ± 1%
LoadAndDeleteBalanced/*sync.Map-12                10.3ns ±11%
LoadAndDeleteUnique/*sync_test.RWMutexMap-12      99.2ns ± 2%
LoadAndDeleteUnique/*sync.Map-12                  6.63ns ±10%
LoadAndDeleteCollision/*sync_test.DeepCopyMap-12   140ns ± 0%
LoadAndDeleteCollision/*sync_test.RWMutexMap-12   75.2ns ± 2%
LoadAndDeleteCollision/*sync.Map-12               5.21ns ± 5%

In addition, Delete is bounded and more efficient if many collisions:

DeleteCollision/*sync_test.DeepCopyMap-12   120ns ± 2%   125ns ± 1%   +3.80%  (p=0.000 n=10+9)
DeleteCollision/*sync_test.RWMutexMap-12   73.5ns ± 3%  79.5ns ± 1%   +8.03%  (p=0.000 n=10+9)
DeleteCollision/*sync.Map-12               97.8ns ± 3%   5.9ns ± 4%  -94.00%  (p=0.000 n=10+10)

Fixes #33762

Change-Id: Ic8469a7861d27ab0edeface0078aad8af9b26c2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/205899
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-02-25 14:31:55 +00:00
Ian Lance Taylor 0915a19a11 sync: deflake TestWaitGroupMisuse3
If one of the helper goroutine panics, the main goroutine call to Wait
may hang forever waiting for something to call Done. Put that call in
a goroutine like the others.

Fixes #35774

Change-Id: I8d2b58d8f473644a49a95338f70111d4e6ed4e12
Reviewed-on: https://go-review.googlesource.com/c/go/+/210218
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2019-12-06 05:12:15 +00:00
Rhys Hiltner 7148478f1b sync: yield to the waiter when unlocking a starving mutex
When we have already assigned the semaphore ticket to a specific
waiter, we want to get the waiter running as fast as possible since
no other G waiting on the semaphore can acquire it optimistically.

The net effect is that, when a sync.Mutex is contended, the code in
the critical section guarded by the Mutex gets a priority boost.

Fixes #33747

The original work was done in CL 200577 by Carlo Alberto Ferraris. The
change was reverted in CL 205817 because it broke the linux-arm64-packet
and solaris-amd64-oraclerel builders.

Change-Id: I76d79b1d63fd206ed1c57fe6900cb7ae9e4d46cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/206180
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-11-09 19:31:32 +00:00
Bryan C. Mills 73d57bf80f Revert "sync: yield to the waiter when unlocking a starving mutex"
This reverts CL 200577.

Reason for revert: broke linux-arm64-packet and solaris-amd64-oraclerel builders

Fixes #35424
Updates #33747

Change-Id: I2575fd84d37995d458183caae54704f15d8b8426
Reviewed-on: https://go-review.googlesource.com/c/go/+/205817
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-11-07 15:04:03 +00:00
Carlo Alberto Ferraris a8f57f4ada sync: yield to the waiter when unlocking a starving mutex
When we have already assigned the semaphore ticket to a specific
waiter, we want to get the waiter running as fast as possible since
no other G waiting on the semaphore can acquire it optimistically.

The net effect is that, when a sync.Mutex is contented, the code in
the critical section guarded by the Mutex gets a priority boost.

Fixes #33747

Change-Id: I9967f0f763c25504010651bdd7f944ee0189cd45
Reviewed-on: https://go-review.googlesource.com/c/go/+/200577
Reviewed-by: Rhys Hiltner <rhys@justin.tv>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-11-07 05:59:33 +00:00
Matthew Dempsky a97ccc8940 sync/atomic: suppress checkptr errors for hammerStoreLoadPointer
This test could be updated to use unsafe.Pointer arithmetic properly
(e.g., see discussion at #34972), but it doesn't seem worthwhile. The
test is just checking that LoadPointer and StorePointer are atomic.

Updates #34972.

Change-Id: I85a8d610c1766cd63136cae686aa8a240a362a18
Reviewed-on: https://go-review.googlesource.com/c/go/+/202597
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-10-22 18:09:03 +00:00
Brad Fitzpatrick 03ef105dae all: remove nacl (part 3, more amd64p32)
Part 1: CL 199499 (GOOS nacl)
Part 2: CL 200077 (amd64p32 files, toolchain)
Part 3: stuff that arguably should've been part of Part 2, but I forgot
        one of my grep patterns when splitting the original CL up into
        two parts.

This one might also have interesting stuff to resurrect for any future
x32 ABI support.

Updates #30439

Change-Id: I2b4143374a253a003666f3c69e776b7e456bdb9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/200318
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-10-10 22:38:38 +00:00
Russ Cox bc593eac2d sync: document implementation of Once.Do
It's not correct to use atomic.CompareAndSwap to implement Once.Do,
and we don't, but why we don't is a question that has come up
twice on golang-dev in the past few months.
Add a comment to help others with the same question.

Change-Id: Ia89ec9715cc5442c6e7f13e57a49c6cfe664d32c
Reviewed-on: https://go-review.googlesource.com/c/go/+/184261
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ingo Oeser <nightlyone@googlemail.com>
2019-07-01 14:45:49 +00:00
Austin Clements 9caaac2c92 sync: only check for successful PopHeads in long mode
In TestPoolDequeue it's surprisingly common for the queue to stay
nearly empty the whole time and for a racing PopTail to happen in the
window between the producer doing a PushHead and doing a PopHead. In
short mode, there are only 100 PopTail attempts. On linux/amd64, it's
not uncommon for this to fail 50% of the time. On linux/arm64, it's
not uncommon for this to fail 100% of the time, causing the test to
fail.

This CL fixes this by only checking for a successful PopTail in long
mode. Long mode makes 200,000 PopTail attempts, and has never been
observed to fail.

Fixes #31422.

Change-Id: If464d55eb94fcb0b8d78fbc441d35be9f056a290
Reviewed-on: https://go-review.googlesource.com/c/go/+/183981
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2019-06-26 19:48:42 +00:00