delta/go-git.git/src/sync, branch dev.typeparams

all: add //go:build lines to assembly files

2021-05-13T09:12:17+00:00

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 
Run-TryBot: Tobias Klauser 
TryBot-Result: Go Bot 
Reviewed-by: Russ Cox

sync/atomic: add (Value).Swap and (Value).CompareAndSwap

2021-05-04T00:15:27+00:00

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 
TryBot-Result: Go Bot 
Reviewed-by: Ian Lance Taylor 
Reviewed-by: Keith Randall

Revert "sync: improve sync.Pool object stealing"

2021-04-26T18:54:39+00:00

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 
Run-TryBot: Bryan C. Mills 
Reviewed-by: Cherry Zhang 
TryBot-Result: Go Bot

sync: improve sync.Pool object stealing

2021-04-26T17:13:36+00:00

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 
Trust: Emmanuel Odeke

sync: update misleading comment in map.go about entry type

2021-04-08T14:08:29+00:00

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: 202c598a0ab98f4634cb56fe2486e8e82f9d991f
GitHub-Pull-Request: golang/go#45443
Reviewed-on: https://go-review.googlesource.com/c/go/+/308292
Reviewed-by: Changkun Ou 
Reviewed-by: Bryan C. Mills 
Run-TryBot: Bryan C. Mills 
Trust: Robert Findley 
TryBot-Result: Go Bot

all: go fmt std cmd (but revert vendor)

2021-02-20T03:54:50+00:00

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 
Run-TryBot: Russ Cox 
TryBot-Result: Go Bot 
Reviewed-by: Jason A. Donenfeld 
Reviewed-by: Ian Lance Taylor

sync: use 386 instead of x86-32 to refer to the 32 bit x86 architecture

2020-11-23T05:57:35+00:00

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 
Run-TryBot: Martin Möhrmann 
TryBot-Result: Go Bot 
Reviewed-by: Ian Lance Taylor

sync: document RWMutex race semantics

2020-11-18T20:12:03+00:00

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 
TryBot-Result: Go Bot 
Reviewed-by: Austin Clements 
Trust: Michael Pratt

cmd/go,cmd/compile,sync: remove special import case in cmd/go

2020-10-26T20:12:53+00:00

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 
Run-TryBot: Austin Clements 
Reviewed-by: Bryan C. Mills 
Reviewed-by: Keith Randall 
Reviewed-by: Paul Murphy 
TryBot-Result: Go Bot

sync: document that Once must not be copied

2020-10-23T19:57:55+00:00

Fixes #42160.

Change-Id: I9bf8b6f0bf1eccd3ab32cbd94c812f768746d291
Reviewed-on: https://go-review.googlesource.com/c/go/+/264557
Trust: Dmitri Shuralyov 
Run-TryBot: Dmitri Shuralyov 
TryBot-Result: Go Bot 
Reviewed-by: Bryan C. Mills