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runtime/pprof: disable profiling test on Windows too? #13871

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bradfitz opened this issue Jan 8, 2016 · 5 comments
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runtime/pprof: disable profiling test on Windows too? #13871

bradfitz opened this issue Jan 8, 2016 · 5 comments
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Go1.6Maybe

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@bradfitz
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bradfitz commented Jan 8, 2016

It appears that Windows also can't do profiles reliably?

https://storage.googleapis.com/go-build-log/5b3db773/windows-amd64-gce_15b35da7.log

--- FAIL: TestStackBarrierProfiling (0.83s)
    pprof_test.go:363: subprocess failed with exit status 1:
        --- FAIL: TestStackBarrierProfiling (0.45s)
            pprof_test.go:97: profile too short: [0x0 0x3 0x0 0x2710 0x0 0x0 0x1 0x0]
        FAIL
FAIL
FAIL    runtime/pprof   2.519s
ok      runtime/trace   6.002s

(part of #13841)
@bradfitz bradfitz added this to the Go1.6 milestone Jan 8, 2016
@aclements
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Windows is known to have reduced timer resolution, though it can't have the common Unix problem of only delivering profiling signals after a full time slice because the Windows APIs couldn't express a bug like that.

I don't see any Windows profiling failures on the dashboard. Could this be related to whatever CL produced that failure?

@bradfitz
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bradfitz commented Jan 8, 2016

If you paste the git rev at the top of that failure log into Gerrit, Gerrit redirects you to the CL it was part of: https://go-review.googlesource.com/#/c/18374/ (an HTTP header validation change)

So, no... it was a flake.

@alexbrainman
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Go profiler is not using signal on Windows. It is running on a separate dedicated OS thread. The thread is running with THREAD_PRIORITY_HIGHEST to make it as reliable as possible, but ... Also the thread is only started on demand - maybe there is some latency to that when CPU is busy.

Alex

@alexbrainman
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Also maybe there is merit to https://go-review.googlesource.com/#/c/11478. @dvyukov said it is not needed, so I abandoned the change.

Alex

@rsc rsc modified the milestones: Go1.6Maybe, Go1.6 Jan 14, 2016
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CL https://golang.org/cl/18683 mentions this issue.

@golang golang locked and limited conversation to collaborators Feb 3, 2017
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