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Issue 112990043: code review 112990043: runtime: fine-grained locking in select

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Created:
5 years, 10 months ago by dvyukov
Modified:
5 years, 5 months ago
Reviewers:
CC:
golang-codereviews, rsc, josharian, khr, rlh, r
Visibility:
Public.

Description

runtime: fine-grained locking in select Never lock more than one channel at a time. Also makes lockorder and channel sorting unnecessary. Details of the algorithm are in comments. benchmark old ns/op new ns/op delta BenchmarkSelectUncontended 213 188 -11.74% BenchmarkSelectUncontended-2 110 97.2 -11.64% BenchmarkSelectUncontended-4 56.2 49.5 -11.92% BenchmarkSelectUncontended-8 29.7 25.9 -12.79% BenchmarkSelectUncontended-16 17.3 16.4 -5.20% BenchmarkSelectUncontended-32 13.7 11.4 -16.79% BenchmarkSelectSyncContended 795 710 -10.69% BenchmarkSelectSyncContended-2 946 710 -24.95% BenchmarkSelectSyncContended-4 1791 1187 -33.72% BenchmarkSelectSyncContended-8 1749 637 -63.58% BenchmarkSelectSyncContended-16 2109 563 -73.30% BenchmarkSelectSyncContended-32 3165 1172 -62.97% BenchmarkSelectAsyncContended 231 208 -9.96% BenchmarkSelectAsyncContended-2 671 209 -68.85% BenchmarkSelectAsyncContended-4 395 215 -45.57% BenchmarkSelectAsyncContended-8 451 240 -46.78% BenchmarkSelectAsyncContended-16 486 233 -52.06% BenchmarkSelectAsyncContended-32 861 395 -54.12% BenchmarkSelectNonblock 126 36.0 -71.43% BenchmarkSelectNonblock-2 155 17.6 -88.65% BenchmarkSelectNonblock-4 285 8.45 -97.04% BenchmarkSelectNonblock-8 212 4.41 -97.92% BenchmarkSelectNonblock-16 180 2.44 -98.64% BenchmarkSelectNonblock-32 395 1.63 -99.59% BenchmarkSelectProdCons 1140 926 -18.77% BenchmarkSelectProdCons-2 653 545 -16.54% BenchmarkSelectProdCons-4 519 352 -32.18% BenchmarkSelectProdCons-8 667 372 -44.23% BenchmarkSelectProdCons-16 751 431 -42.61% BenchmarkSelectProdCons-32 1142 583 -48.95%

Patch Set 1 #

Patch Set 2 : diff -r 141e6dead8db https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 3 : diff -r c0a68bcf19ae https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 4 : diff -r c0a68bcf19ae https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 5 : diff -r c0a68bcf19ae https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 6 : diff -r 67f9ef140028 https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 7 : diff -r 67f9ef140028 https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 8 : diff -r 03b003455359b09fff0f1662255dc5fe10b93290 https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 9 : diff -r 03b003455359b09fff0f1662255dc5fe10b93290 https://dvyukov%40google.com@code.google.com/p/go/ #

Patch Set 10 : diff -r 03b003455359b09fff0f1662255dc5fe10b93290 https://dvyukov%40google.com@code.google.com/p/go/ #

Unified diffs Side-by-side diffs Delta from patch set Stats (+462 lines, -288 lines) Patch
M src/cmd/gc/select.c View 1 2 3 4 5 6 7 8 1 chunk +0 lines, -3 lines 0 comments Download
M src/pkg/runtime/chan.h View 1 2 3 4 5 6 7 8 1 chunk +0 lines, -1 line 0 comments Download
M src/pkg/runtime/chan.go View 1 2 3 4 5 6 7 8 6 chunks +121 lines, -31 lines 0 comments Download
M src/pkg/runtime/chan.goc View 1 2 3 4 5 6 7 8 27 chunks +332 lines, -252 lines 0 comments Download
M src/pkg/runtime/runtime.h View 1 2 3 4 5 6 7 1 chunk +1 line, -1 line 0 comments Download
M src/pkg/runtime/stubs.go View 1 2 3 4 5 6 7 1 chunk +3 lines, -0 lines 0 comments Download
M src/pkg/runtime/stubs.goc View 1 2 3 4 5 6 7 1 chunk +5 lines, -0 lines 0 comments Download

Messages

Total messages: 7
dvyukov
Hello golang-codereviews@googlegroups.com, I'd like you to review this change to https://dvyukov%40google.com@code.google.com/p/go/
5 years, 10 months ago (2014-07-14 12:00:24 UTC) #1
rsc
not reviewing until the other CL is worked out
5 years, 10 months ago (2014-07-16 11:42:37 UTC) #2
dvyukov
On 2014/07/16 11:42:37, rsc wrote: > not reviewing until the other CL is worked out ...
5 years, 9 months ago (2014-08-25 14:07:25 UTC) #3
dvyukov
Quick benchmarking shows that the win still holds: benchmark old ns/op new ns/op delta BenchmarkSelectUncontended ...
5 years, 9 months ago (2014-08-25 14:09:03 UTC) #4
josharian
This no longer applies cleanly to tip.
5 years, 9 months ago (2014-08-26 20:35:42 UTC) #5
dvyukov
On Wed, Aug 27, 2014 at 12:35 AM, <josharian@gmail.com> wrote: > This no longer applies ...
5 years, 9 months ago (2014-08-30 13:04:50 UTC) #6
gobot
5 years, 5 months ago (2014-12-19 05:10:33 UTC) #7
R=close

To the author of this CL:

The Go project has moved to Gerrit Code Review.

If this CL should be continued, please see the latest version of
https://golang.org/doc/contribute.html for instructions on
how to set up Git and the Go project's Gerrit codereview plugin,
and then create a new change with your current code.

If there has been discussion on this CL, please give a link to it
(golang.org/cl/112990043 is best) in the description in your
new CL.

Thanks very much.
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