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| author | Dmitry Vyukov <dvyukov@google.com> | 2016-01-27 19:22:28 +0100 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2016-01-27 20:49:36 +0000 |
| commit | 572f7660a774ebd8552408a6058b36cc90f6f563 (patch) | |
| tree | 635b05ea9130f6ded5621a525a77bbd9eac5ecef | |
| parent | d326a9641994eccdac1c95901762af45ec801bf1 (diff) | |
| download | go-572f7660a774ebd8552408a6058b36cc90f6f563.tar.gz go-572f7660a774ebd8552408a6058b36cc90f6f563.zip | |
runtime/race: run tests with GOMAXPROCS=1
We set GOMAXPROCS=1 to prevent test flakiness.
There are two sources of flakiness:
1. Some tests rely on particular execution order.
If the order is different, race does not happen at all.
2. Ironically, ThreadSanitizer runtime contains a logical race condition
that can lead to false negatives if racy accesses happen literally at the same time.
Tests used to work reliably in the good old days of GOMAXPROCS=1.
So let's set it for now. A more reliable solution is to explicitly annotate tests
with required execution order by means of a special "invisible" synchronization primitive
(that's what is done for C++ ThreadSanitizer tests). This is issue #14119.
This reduces flakes on RaceAsFunc3 test from 60/3000 to 1/3000.
Fixes #14086
Fixes #14079
Fixes #14035
Change-Id: Ibaec6b2b21e27b62563bffbb28473a854722cf41
Reviewed-on: https://go-review.googlesource.com/18968
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
| -rw-r--r-- | src/runtime/race/output_test.go | 5 | ||||
| -rw-r--r-- | src/runtime/race/race_test.go | 15 |
2 files changed, 18 insertions, 2 deletions
diff --git a/src/runtime/race/output_test.go b/src/runtime/race/output_test.go index a9f9f0fbd5..0c71a019dd 100644 --- a/src/runtime/race/output_test.go +++ b/src/runtime/race/output_test.go @@ -51,7 +51,10 @@ func TestOutput(t *testing.T) { } cmd.Env = append(cmd.Env, env) } - cmd.Env = append(cmd.Env, "GORACE="+test.gorace) + cmd.Env = append(cmd.Env, + "GOMAXPROCS=1", // see comment in race_test.go + "GORACE="+test.gorace, + ) got, _ := cmd.CombinedOutput() if !regexp.MustCompile(test.re).MatchString(string(got)) { t.Fatalf("failed test case %v, expect:\n%v\ngot:\n%s", diff --git a/src/runtime/race/race_test.go b/src/runtime/race/race_test.go index 6898e74900..748f33883b 100644 --- a/src/runtime/race/race_test.go +++ b/src/runtime/race/race_test.go @@ -155,7 +155,20 @@ func runTests() ([]byte, error) { } cmd.Env = append(cmd.Env, env) } - cmd.Env = append(cmd.Env, `GORACE=suppress_equal_stacks=0 suppress_equal_addresses=0 exitcode=0`) + // We set GOMAXPROCS=1 to prevent test flakiness. + // There are two sources of flakiness: + // 1. Some tests rely on particular execution order. + // If the order is different, race does not happen at all. + // 2. Ironically, ThreadSanitizer runtime contains a logical race condition + // that can lead to false negatives if racy accesses happen literally at the same time. + // Tests used to work reliably in the good old days of GOMAXPROCS=1. + // So let's set it for now. A more reliable solution is to explicitly annotate tests + // with required execution order by means of a special "invisible" synchronization primitive + // (that's what is done for C++ ThreadSanitizer tests). This is issue #14119. + cmd.Env = append(cmd.Env, + "GOMAXPROCS=1", + "GORACE=suppress_equal_stacks=0 suppress_equal_addresses=0 exitcode=0", + ) return cmd.CombinedOutput() } |