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2023-01-20sync: document memory model for Swap/CompareAnd{Swap,Delete} in MapChangkun Ou
CL 381316 documented the memory model of Map's APIs. However, the newly introduced Swap, CompareAndSwap, and CompareAndDelete are missing from this documentation as CL 399094 did not add this info. This CL specifies the defined read/write operations of the new Map APIs. For #51972 Change-Id: I519a04040a0b429a3f978823a183cd62e42c90ae Reviewed-on: https://go-review.googlesource.com/c/go/+/459715 TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Run-TryBot: Changkun Ou <mail@changkun.de> Auto-Submit: Bryan Mills <bcmills@google.com> Reviewed-by: Bryan Mills <bcmills@google.com>
2022-11-15sync: add new Map method Swap, CompareAndSwap, CompareAndDeleteChangkun Ou
name time/op SwapCollision/*sync_test.DeepCopyMap-8 235ns ± 0% SwapCollision/*sync_test.RWMutexMap-8 145ns ± 0% SwapCollision/*sync.Map-8 153ns ± 0% SwapMostlyHits/*sync_test.DeepCopyMap-8 48.2µs ± 0% SwapMostlyHits/*sync_test.RWMutexMap-8 190ns ± 0% SwapMostlyHits/*sync.Map-8 28.3ns ± 0% SwapMostlyMisses/*sync_test.DeepCopyMap-8 681ns ± 0% SwapMostlyMisses/*sync_test.RWMutexMap-8 336ns ± 0% SwapMostlyMisses/*sync.Map-8 523ns ± 0% CompareAndSwapCollision/*sync_test.DeepCopyMap-8 3.99ns ± 0% CompareAndSwapCollision/*sync_test.RWMutexMap-8 151ns ± 0% CompareAndSwapCollision/*sync.Map-8 21.6ns ± 0% CompareAndSwapNoExistingKey/*sync_test.DeepCopyMap-8 3.95ns ± 0% CompareAndSwapNoExistingKey/*sync_test.RWMutexMap-8 126ns ± 0% CompareAndSwapNoExistingKey/*sync.Map-8 6.11ns ± 0% CompareAndSwapValueNotEqual/*sync_test.DeepCopyMap-8 2.15ns ± 0% CompareAndSwapValueNotEqual/*sync_test.RWMutexMap-8 132ns ± 0% CompareAndSwapValueNotEqual/*sync.Map-8 5.32ns ± 0% CompareAndSwapMostlyHits/*sync_test.RWMutexMap-8 219ns ± 0% CompareAndSwapMostlyHits/*sync.Map-8 27.1ns ± 0% CompareAndSwapMostlyMisses/*sync_test.DeepCopyMap-8 13.0ns ± 0% CompareAndSwapMostlyMisses/*sync_test.RWMutexMap-8 147ns ± 0% CompareAndSwapMostlyMisses/*sync.Map-8 19.6ns ± 0% CompareAndDeleteCollision/*sync_test.DeepCopyMap-8 2.23ns ± 0% CompareAndDeleteCollision/*sync_test.RWMutexMap-8 131ns ± 0% CompareAndDeleteCollision/*sync.Map-8 16.2ns ± 0% CompareAndDeleteMostlyHits/*sync_test.RWMutexMap-8 367ns ± 0% CompareAndDeleteMostlyHits/*sync.Map-8 33.1ns ± 0% CompareAndDeleteMostlyMisses/*sync_test.DeepCopyMap-8 8.75ns ± 0% CompareAndDeleteMostlyMisses/*sync_test.RWMutexMap-8 134ns ± 0% CompareAndDeleteMostlyMisses/*sync.Map-8 10.9ns ± 0% name alloc/op SwapCollision/*sync_test.DeepCopyMap-8 336B ± 0% SwapCollision/*sync_test.RWMutexMap-8 0.00B SwapCollision/*sync.Map-8 16.0B ± 0% SwapMostlyHits/*sync_test.DeepCopyMap-8 82.1kB ± 0% SwapMostlyHits/*sync_test.RWMutexMap-8 12.0B ± 0% SwapMostlyHits/*sync.Map-8 28.0B ± 0% SwapMostlyMisses/*sync_test.DeepCopyMap-8 713B ± 0% SwapMostlyMisses/*sync_test.RWMutexMap-8 23.0B ± 0% SwapMostlyMisses/*sync.Map-8 129B ± 0% CompareAndSwapCollision/*sync_test.DeepCopyMap-8 0.00B CompareAndSwapCollision/*sync_test.RWMutexMap-8 0.00B CompareAndSwapCollision/*sync.Map-8 3.00B ± 0% CompareAndSwapNoExistingKey/*sync_test.DeepCopyMap-8 8.00B ± 0% CompareAndSwapNoExistingKey/*sync_test.RWMutexMap-8 8.00B ± 0% CompareAndSwapNoExistingKey/*sync.Map-8 8.00B ± 0% CompareAndSwapValueNotEqual/*sync_test.DeepCopyMap-8 0.00B CompareAndSwapValueNotEqual/*sync_test.RWMutexMap-8 0.00B CompareAndSwapValueNotEqual/*sync.Map-8 0.00B CompareAndSwapMostlyHits/*sync_test.RWMutexMap-8 18.0B ± 0% CompareAndSwapMostlyHits/*sync.Map-8 33.0B ± 0% CompareAndSwapMostlyMisses/*sync_test.DeepCopyMap-8 24.0B ± 0% CompareAndSwapMostlyMisses/*sync_test.RWMutexMap-8 23.0B ± 0% CompareAndSwapMostlyMisses/*sync.Map-8 23.0B ± 0% CompareAndDeleteCollision/*sync_test.DeepCopyMap-8 0.00B CompareAndDeleteCollision/*sync_test.RWMutexMap-8 0.00B CompareAndDeleteCollision/*sync.Map-8 0.00B CompareAndDeleteMostlyHits/*sync_test.RWMutexMap-8 23.0B ± 0% CompareAndDeleteMostlyHits/*sync.Map-8 39.0B ± 0% CompareAndDeleteMostlyMisses/*sync_test.DeepCopyMap-8 16.0B ± 0% CompareAndDeleteMostlyMisses/*sync_test.RWMutexMap-8 15.0B ± 0% CompareAndDeleteMostlyMisses/*sync.Map-8 15.0B ± 0% name allocs/op SwapCollision/*sync_test.DeepCopyMap-8 2.00 ± 0% SwapCollision/*sync_test.RWMutexMap-8 0.00 SwapCollision/*sync.Map-8 1.00 ± 0% SwapMostlyHits/*sync_test.DeepCopyMap-8 4.00 ± 0% SwapMostlyHits/*sync_test.RWMutexMap-8 1.00 ± 0% SwapMostlyHits/*sync.Map-8 2.00 ± 0% SwapMostlyMisses/*sync_test.DeepCopyMap-8 6.00 ± 0% SwapMostlyMisses/*sync_test.RWMutexMap-8 2.00 ± 0% SwapMostlyMisses/*sync.Map-8 6.00 ± 0% CompareAndSwapCollision/*sync_test.DeepCopyMap-8 0.00 CompareAndSwapCollision/*sync_test.RWMutexMap-8 0.00 CompareAndSwapCollision/*sync.Map-8 0.00 CompareAndSwapNoExistingKey/*sync_test.DeepCopyMap-8 1.00 ± 0% CompareAndSwapNoExistingKey/*sync_test.RWMutexMap-8 0.00 CompareAndSwapNoExistingKey/*sync.Map-8 1.00 ± 0% CompareAndSwapValueNotEqual/*sync_test.DeepCopyMap-8 0.00 CompareAndSwapValueNotEqual/*sync_test.RWMutexMap-8 0.00 CompareAndSwapValueNotEqual/*sync.Map-8 0.00 CompareAndSwapMostlyHits/*sync_test.RWMutexMap-8 2.00 ± 0% CompareAndSwapMostlyHits/*sync.Map-8 3.00 ± 0% CompareAndSwapMostlyMisses/*sync_test.DeepCopyMap-8 2.00 ± 0% CompareAndSwapMostlyMisses/*sync_test.RWMutexMap-8 2.00 ± 0% CompareAndSwapMostlyMisses/*sync.Map-8 2.00 ± 0% CompareAndDeleteCollision/*sync_test.DeepCopyMap-8 0.00 CompareAndDeleteCollision/*sync_test.RWMutexMap-8 0.00 CompareAndDeleteCollision/*sync.Map-8 0.00 CompareAndDeleteMostlyHits/*sync_test.RWMutexMap-8 2.00 ± 0% CompareAndDeleteMostlyHits/*sync.Map-8 3.00 ± 0% CompareAndDeleteMostlyMisses/*sync_test.DeepCopyMap-8 2.00 ± 0% CompareAndDeleteMostlyMisses/*sync_test.RWMutexMap-8 1.00 ± 0% CompareAndDeleteMostlyMisses/*sync.Map-8 1.00 ± 0% Fixes #51972 Change-Id: I469e71033592997832c3e8ebdad1b8950a70c99c Reviewed-on: https://go-review.googlesource.com/c/go/+/399094 Run-TryBot: Changkun Ou <mail@changkun.de> Reviewed-by: Joedian Reid <joedian@golang.org> Auto-Submit: Bryan Mills <bcmills@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Bryan Mills <bcmills@google.com>
2022-10-31sync: use atomic.Pointer for entryChangkun Ou
Change-Id: Ie3b4bfe483d7ef43da29ea1dd73d423dac36cf39 Reviewed-on: https://go-review.googlesource.com/c/go/+/432055 Auto-Submit: Bryan Mills <bcmills@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Bryan Mills <bcmills@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Run-TryBot: Changkun Ou <mail@changkun.de>
2022-08-29sync: switch Map to use atomic.PointerJoe Tsai
There was no noticeable change in performance. Change-Id: I9c57bf836c8b6066e0620afb3d536ce99e4b9d87 Reviewed-on: https://go-review.googlesource.com/c/go/+/426074 Reviewed-by: Bryan Mills <bcmills@google.com> Reviewed-by: Heschi Kreinick <heschi@google.com> Auto-Submit: Joseph Tsai <joetsai@digital-static.net> Run-TryBot: Joseph Tsai <joetsai@digital-static.net> TryBot-Result: Gopher Robot <gobot@golang.org>
2022-06-06runtime, sync, sync/atomic: document happens-before guaranteesRuss Cox
A few of these are copied from the memory model doc. Many are entirely new, following discussion on #47141. See https://research.swtch.com/gomm for background. The rule we are establishing is that each type that is meant to help synchronize a Go program should document its happens-before guarantees. For #50859. Change-Id: I947c40639b263abe67499fa74f68711a97873a39 Reviewed-on: https://go-review.googlesource.com/c/go/+/381316 Auto-Submit: Russ Cox <rsc@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Alan Donovan <adonovan@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Roland Shoemaker <roland@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>
2021-11-11sync: clarify the validity to call Map methods inside RangeChangkun Ou
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>
2021-04-08sync: update misleading comment in map.go about entry typepanchenglong01
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 <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>
2020-08-24sync: delete dirty keys inside Map.LoadAndDeleteChangkun Ou
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>
2020-02-25sync: add new Map method LoadAndDeleteChangkun Ou
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>
2018-09-27sync: simplify (*entry).tryStoreIan Lance Taylor
The only change to the go build -gcflags=-m=2 output was to remove these two lines: sync/map.go:178:26: &e.p escapes to heap sync/map.go:178:26: from &e.p (passed to call[argument escapes]) at sync/map.go:178:25 Benchstat report for sync.Map benchmarks: name old time/op new time/op delta LoadMostlyHits/*sync_test.DeepCopyMap-12 10.6ns ±11% 10.2ns ± 3% ~ (p=0.299 n=10+8) LoadMostlyHits/*sync_test.RWMutexMap-12 54.6ns ± 3% 54.6ns ± 2% ~ (p=0.782 n=10+10) LoadMostlyHits/*sync.Map-12 10.1ns ± 1% 10.1ns ± 1% ~ (p=1.127 n=10+8) LoadMostlyMisses/*sync_test.DeepCopyMap-12 8.65ns ± 1% 8.77ns ± 5% +1.39% (p=0.017 n=9+10) LoadMostlyMisses/*sync_test.RWMutexMap-12 53.6ns ± 2% 53.8ns ± 2% ~ (p=0.408 n=10+9) LoadMostlyMisses/*sync.Map-12 7.37ns ± 1% 7.46ns ± 1% +1.19% (p=0.000 n=9+10) LoadOrStoreBalanced/*sync_test.RWMutexMap-12 895ns ± 4% 906ns ± 3% ~ (p=0.203 n=9+10) LoadOrStoreBalanced/*sync.Map-12 872ns ±10% 804ns ±12% -7.75% (p=0.014 n=10+10) LoadOrStoreUnique/*sync_test.RWMutexMap-12 1.29µs ± 2% 1.28µs ± 1% ~ (p=0.586 n=10+9) LoadOrStoreUnique/*sync.Map-12 1.30µs ± 7% 1.40µs ± 2% +6.95% (p=0.000 n=9+10) LoadOrStoreCollision/*sync_test.DeepCopyMap-12 6.98ns ± 1% 6.91ns ± 1% -1.10% (p=0.000 n=10+10) LoadOrStoreCollision/*sync_test.RWMutexMap-12 371ns ± 1% 372ns ± 2% ~ (p=0.679 n=9+9) LoadOrStoreCollision/*sync.Map-12 5.49ns ± 1% 5.49ns ± 1% ~ (p=0.732 n=9+10) Range/*sync_test.DeepCopyMap-12 2.49µs ± 1% 2.50µs ± 0% ~ (p=0.148 n=10+10) Range/*sync_test.RWMutexMap-12 54.7µs ± 1% 54.6µs ± 3% ~ (p=0.549 n=9+10) Range/*sync.Map-12 2.74µs ± 1% 2.76µs ± 1% +0.68% (p=0.011 n=10+8) AdversarialAlloc/*sync_test.DeepCopyMap-12 2.52µs ± 5% 2.54µs ± 7% ~ (p=0.225 n=10+10) AdversarialAlloc/*sync_test.RWMutexMap-12 108ns ± 1% 107ns ± 1% ~ (p=0.101 n=10+9) AdversarialAlloc/*sync.Map-12 712ns ± 2% 714ns ± 3% ~ (p=0.984 n=8+10) AdversarialDelete/*sync_test.DeepCopyMap-12 581ns ± 3% 578ns ± 3% ~ (p=0.781 n=9+9) AdversarialDelete/*sync_test.RWMutexMap-12 126ns ± 2% 126ns ± 1% ~ (p=0.883 n=10+10) AdversarialDelete/*sync.Map-12 155ns ± 8% 158ns ± 2% ~ (p=0.158 n=10+9) Change-Id: I1ed8e3109baca03087d0fad3df769fc7e38f6dbb Reviewed-on: https://go-review.googlesource.com/137441 Reviewed-by: Bryan C. Mills <bcmills@google.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-01-04sync: document when and when not to use MapRuss Cox
Fixes #21587. Change-Id: I47eb181d65da67a3b530c7f8acac9c0c619ea474 Reviewed-on: https://go-review.googlesource.com/83796 Run-TryBot: Russ Cox <rsc@golang.org> Reviewed-by: Bryan Mills <bcmills@google.com> Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-21sync: delete a sentence from the Map docsBrad Fitzpatrick
From Josh's comments on https://golang.org/cl/50310 Once I removed the "from the Go standard library" bit, the beginning wasn't worth keeping. It also wasn't clear whether what it meant by "cache contention". Processor caches, or user-level caches built with sync.Map? It didn't seem worth clarifying and didn't convey any useful information, so deleted. Change-Id: Id1d76105a3081d0855f6a64540700932bb83d98e Reviewed-on: https://go-review.googlesource.com/50632 Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Bryan Mills <bcmills@google.com>
2017-07-21sync: update Map documentation with usage rule of thumbMichael Stapelberg
As per bcmills’s lightning talk at GopherCon 2017: https://github.com/gophercon/2017-talks/tree/master/lightningtalks/BryanCMills-AnOverviewOfSyncMap Change-Id: I12dd0daa608af175d110298780f32c6dc5e1e0a0 Reviewed-on: https://go-review.googlesource.com/50310 Reviewed-by: Bryan Mills <bcmills@google.com>
2017-04-26sync: import Map from x/sync/syncmapBryan C. Mills
This is a direct port of the version from commit a60ad46e0ed33d02e09bda439efaf9c9727dbc6c (https://go-review.googlesource.com/c/37342/). updates #17973 updates #18177 Change-Id: I63fa5ef6951b1edd39f84927d1181a4df9b15385 Reviewed-on: https://go-review.googlesource.com/36617 Reviewed-by: Russ Cox <rsc@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
generated by cgit v1.3 (git 2.53.0) at 2026-04-15 13:22:35 +0000