runtime: TestWindowsStackMemory flakes on windows-386-2016

[prattmic]

#!watchflakes
post <- pkg == "runtime" && test == "TestWindowsStackMemory"

2023-01-17T19:55:02-d4639ec/windows-386-2016

--- FAIL: TestWindowsStackMemory (0.03s)
    crash_test.go:58: C:\Users\gopher\AppData\Local\Temp\1\go-build1812702813\testprog.exe StackMemory (27.351ms): ok
    syscall_windows_test.go:675: expected < 102400 bytes of memory per thread, got 103424
FAIL
FAIL	runtime	47.304s

Notes:

• This is on the brand new windows-386-2016 builder.
• The test computes the average assuming there are 100 threads. If there are actually 101 threads (the test doesn't consider sysmon...), then the average comes out to exactly 102400 bytes.

cc @mknyszek @golang/runtime @golang/windows

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- pkg == "runtime" && test == "TestWindowsStackMemory"

2023-01-17 19:55 windows-386-2016 go@d4639ecd runtime.TestWindowsStackMemory (log)

--- FAIL: TestWindowsStackMemory (0.03s)
    crash_test.go:58: C:\Users\gopher\AppData\Local\Temp\1\go-build1812702813\testprog.exe StackMemory (27.351ms): ok
    syscall_windows_test.go:675: expected < 102400 bytes of memory per thread, got 103424

— watchflakes

[alexbrainman]

• The test computes the average assuming there are 100 threads. If there are actually 101 threads (the test doesn't consider sysmon...), then the average comes out to exactly 102400 bytes.

The test was suggested by @aclements at #22439 (comment) . You should be able to adjust the test to allow for a couple of extra threads to be started by runtime without TestWindowsStackMemory noticing. But we want to keep the test to prevent regressions like this one #22439.

Alex.

[mknyszek]

In triage, I think we agree this is a test issue. @alexbrainman up for sending a patch? If not one of us will get around to it (especially if it happens again).

[prattmic]

On CL 473275: https://storage.googleapis.com/go-build-log/67b9e0cb/windows-386-2016_1815f49f.log

[gopherbot]

Change https://go.dev/cl/473415 mentions this issue: runtime: allow for 5 more threads in TestWindowsStackMemory*

[alexbrainman]

@alexbrainman up for sending a patch?

Here is my CL

https://go-review.googlesource.com/c/go/+/473415

Alex