• Dmitry Vyukov's avatar
    runtime/race: run tests with GOMAXPROCS=1 · 572f7660
    Dmitry Vyukov authored
    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/18968Reviewed-by: 's avatarAustin Clements <austin@google.com>
    Run-TryBot: Austin Clements <austin@google.com>
    Reviewed-by: 's avatarRuss Cox <rsc@golang.org>
    TryBot-Result: Gobot Gobot <gobot@golang.org>
    572f7660
output_test.go 3.46 KB