runtime/pprof: disable profiling test on Windows too?

[bradfitz]

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)

[aclements]

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]

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]

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]

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

[gopherbot]

CL https://golang.org/cl/18683 mentions this issue.