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path: root/src/sync/pool_test.go
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2025-05-16sync: set GOMAXPROCS to 1 in TestPoolGCMichael Anthony Knyszek
This test expects to be able to drain a Pool using only Get. This isn't actually possible in the general case, since a pooled value could get stuck in some P's private slot. However, if GOMAXPROCS=1, there's only 1 P we could be running on, so getting stuck becomes impossible. This test isn't checking any concurrent properties of Pool, so this is fine. Just set GOMAXPROCS=1 for this one particular test. Fixes #73728. Change-Id: I9053e28118060650f2cd7d0d58f5a86d630b36f7 Reviewed-on: https://go-review.googlesource.com/c/go/+/673375 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2025-05-14sync: use blockUntilCleanupQueueEmpty instead of busy-looping in testsMichael Anthony Knyszek
testPool currently does the old-style busy loop to wait until cleanups have executed. Clean this up by using the linkname'd blockUntilCleanupQueueEmpty. For #73642. Change-Id: Ie0c2614db858a984f25b33a805dc52948069eb52 Reviewed-on: https://go-review.googlesource.com/c/go/+/671675 Reviewed-by: Michael Pratt <mpratt@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2025-02-14sync: use runtime.AddCleanup instead of runtime.SetFinalizerCarlos Amedee
This changes the use of finalizers to the cleanup implementation in tests. Updates #70907 Change-Id: I7d7289999a83fa53f538698f34294f7d9651c921 Reviewed-on: https://go-review.googlesource.com/c/go/+/640735 Reviewed-by: Ian Lance Taylor <iant@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-05-23all: change from sort functions to slices functions where feasibleIan Lance Taylor
Doing this because the slices functions are slightly faster and slightly easier to use. It also removes one dependency layer. This CL does not change packages that are used during bootstrap, as the bootstrap compiler does not have the required slices functions. It does not change the go/scanner package because the ErrorList Len, Swap, and Less methods are part of the Go 1 API. Change-Id: If52899be791c829198e11d2408727720b91ebe8a Reviewed-on: https://go-review.googlesource.com/c/go/+/587655 LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Commit-Queue: Ian Lance Taylor <iant@google.com> Reviewed-by: Damien Neil <dneil@google.com>
2023-07-31sync: panic rather than throw on nil *PoolIan Lance Taylor
Fixes #61651 Change-Id: I27d581719e6bf38910f9d47dcf023bbff74ddf72 Reviewed-on: https://go-review.googlesource.com/c/go/+/514037 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Auto-Submit: Ian Lance Taylor <iant@google.com> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Ian Lance Taylor <iant@google.com>
2022-04-05all: separate doc comment from //go: directivesRuss Cox
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>
2021-12-13all: gofmt -w -r 'interface{} -> any' srcRuss Cox
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>
2021-11-01sync: add PoolStarvation benchmarkRuslan Andreev
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>
2021-10-28all: go fix -fix=buildtag std cmd (except for bootstrap deps, vendor)Russ Cox
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>
2021-04-26Revert "sync: improve sync.Pool object stealing"Bryan C. Mills
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>
2021-04-26sync: improve sync.Pool object stealingRuslan Andreev
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>
2021-02-20all: go fmt std cmd (but revert vendor)Russ Cox
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>
2019-06-26sync: only check for successful PopHeads in long modeAustin Clements
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>
2019-06-26sync: make TestPoolDequeue termination condition more robustAustin Clements
TestPoolDequeue creates P-1 consumer goroutines and 1 producer goroutine. Currently, if a consumer goroutine pops the last value from the dequeue, it sets a flag that stops all consumers, but the producer also periodically pops from the dequeue and doesn't set this flag. Hence, if the producer were to pop the last element, the consumers will continue to run and the test won't terminate. This CL fixes this by also setting the termination flag in the producer. I believe it's impossible for this to happen right now because the producer only pops after pushing an element for which j%10==0 and the last element is either 999 or 1999999, which means it should never try to pop after pushing the last element. However, we shouldn't depend on this reasoning. Change-Id: Icd2bc8d7cb9a79ebfcec99e367c8a2ba76e027d8 Reviewed-on: https://go-review.googlesource.com/c/go/+/183980 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Bryan C. Mills <bcmills@google.com>
2019-06-26sync: fix pool wrap-around testAustin Clements
TestPoolDequeue in long mode does a little more than 1<<21 pushes. This was originally because the head and tail indexes were 21 bits and the intent was to test wrap-around behavior. However, in the final version they were both 32 bits, so the test no longer tested wrap-around. It would take too long to reach 32-bit wrap around in a test, so instead we initialize the poolDequeue with indexes that are already nearly at their limit. This keeps the knowledge of the maximum index in one place, and lets us test wrap-around even in short mode. Change-Id: Ib9b8d85b6d9b5be235849c2b32e81c809e806579 Reviewed-on: https://go-review.googlesource.com/c/go/+/183979 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Bryan C. Mills <bcmills@google.com>
2019-05-22all: shorten some testsRuss Cox
Shorten some of the longest tests that run during all.bash. Removes 7r 50u 21s from all.bash. After this change, all.bash is under 5 minutes again on my laptop. For #26473. Change-Id: Ie0460aa935808d65460408feaed210fbaa1d5d79 Reviewed-on: https://go-review.googlesource.com/c/go/+/177559 Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-04-05sync: smooth out Pool behavior over GC with a victim cacheAustin Clements
Currently, every Pool is cleared completely at the start of each GC. This is a problem for heavy users of Pool because it causes an allocation spike immediately after Pools are clear, which impacts both throughput and latency. This CL fixes this by introducing a victim cache mechanism. Instead of clearing Pools, the victim cache is dropped and the primary cache is moved to the victim cache. As a result, in steady-state, there are (roughly) no new allocations, but if Pool usage drops, objects will still be collected within two GCs (as opposed to one). This victim cache approach also improves Pool's impact on GC dynamics. The current approach causes all objects in Pools to be short lived. However, if an application is in steady state and is just going to repopulate its Pools, then these objects impact the live heap size *as if* they were long lived. Since Pooled objects count as short lived when computing the GC trigger and goal, but act as long lived objects in the live heap, this causes GC to trigger too frequently. If Pooled objects are a non-trivial portion of an application's heap, this increases the CPU overhead of GC. The victim cache lets Pooled objects affect the GC trigger and goal as long-lived objects. This has no impact on Get/Put performance, but substantially reduces the impact to the Pool user when a GC happens. PoolExpensiveNew demonstrates this in the substantially reduction in the rate at which the "New" function is called. name old time/op new time/op delta Pool-12 2.21ns ±36% 2.00ns ± 0% ~ (p=0.070 n=19+16) PoolOverflow-12 587ns ± 1% 583ns ± 1% -0.77% (p=0.000 n=18+18) PoolSTW-12 5.57µs ± 3% 4.52µs ± 4% -18.82% (p=0.000 n=20+19) PoolExpensiveNew-12 3.69ms ± 7% 1.25ms ± 5% -66.25% (p=0.000 n=20+19) name old p50-ns/STW new p50-ns/STW delta PoolSTW-12 5.48k ± 2% 4.53k ± 2% -17.32% (p=0.000 n=20+20) name old p95-ns/STW new p95-ns/STW delta PoolSTW-12 6.69k ± 4% 5.13k ± 3% -23.31% (p=0.000 n=19+18) name old GCs/op new GCs/op delta PoolExpensiveNew-12 0.39 ± 1% 0.32 ± 2% -17.95% (p=0.000 n=18+20) name old New/op new New/op delta PoolExpensiveNew-12 40.0 ± 6% 12.4 ± 6% -68.91% (p=0.000 n=20+19) (https://perf.golang.org/search?q=upload:20190311.2) Fixes #22950. Change-Id: If2e183d948c650417283076aacc20739682cdd70 Reviewed-on: https://go-review.googlesource.com/c/go/+/166961 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2019-04-05sync: add Pool benchmarks to stress STW and reuseAustin Clements
This adds two benchmarks that will highlight two problems in Pool that we're about to address. The first benchmark measures the impact of large Pools on GC STW time. Currently, STW time is O(# of items in Pools), and this benchmark demonstrates 70µs STW times. The second benchmark measures the impact of fully clearing all Pools on each GC. Typically this is a problem in heavily-loaded systems because it causes a spike in allocation. This benchmark stresses this by simulating an expensive "New" function, so the cost of creating new objects is reflected in the ns/op of the benchmark. For #22950, #22331. Change-Id: I0c8853190d23144026fa11837b6bf42adc461722 Reviewed-on: https://go-review.googlesource.com/c/go/+/166959 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2019-04-05sync: internal dynamically sized lock-free queue for sync.PoolAustin Clements
This adds a dynamically sized, lock-free, single-producer, multi-consumer queue that will be used in the new Pool stealing implementation. It's built on top of the fixed-size queue added in the previous CL. For #22950, #22331. Change-Id: Ifc0ca3895bec7e7f9289ba9fb7dd0332bf96ba5a Reviewed-on: https://go-review.googlesource.com/c/go/+/166958 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2019-04-05sync: internal fixed size lock-free queue for sync.PoolAustin Clements
This is the first step toward fixing multiple issues with sync.Pool. This adds a fixed size, lock-free, single-producer, multi-consumer queue that will be used in the new Pool stealing implementation. For #22950, #22331. Change-Id: I50e85e3cb83a2ee71f611ada88e7f55996504bb5 Reviewed-on: https://go-review.googlesource.com/c/go/+/166957 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2017-06-28sync: deflake TestPool and TestPoolNewAliaksandr Valialkin
Prevent possible goroutine rescheduling to another P between Put and Get calls by locking the goroutine to OS thread. Inspired by the CL 42770. Fixes #20198. Change-Id: I18e24fcad1630658713e6b9d80d90d7941f604be Reviewed-on: https://go-review.googlesource.com/44310 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2016-11-15all: don't call t.Fatal from a goroutineIan Lance Taylor
Fixes #17900. Change-Id: I42cda6ac9cf48ed739d3a015a90b3cb15edf8ddf Reviewed-on: https://go-review.googlesource.com/33243 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2014-10-22sync: release Pool memory during second and later GCsDmitriy Vyukov
Pool memory was only being released during the first GC after the first Put. Put assumes that p.local != nil means p is on the allPools list. poolCleanup (called during each GC) removed each pool from allPools but did not clear p.local, so each pool was cleared by exactly one GC and then never cleared again. This bug was introduced late in the Go 1.3 release cycle. Fixes #8979. LGTM=rsc R=golang-codereviews, bradfitz, r, rsc CC=golang-codereviews, khr https://golang.org/cl/162980043
2014-09-08build: move package sources from src/pkg to srcRuss Cox
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.