os: TestClosedPipeRaceWrite fails on ppc64x

[mundaym]

This new test, added in e3d7ec0, seems to have broken the ppc64x builders.

--- FAIL: TestClosedPipeRaceWrite (0.00s)
	pipe_test.go:157: I/O on closed pipe unexpectedly succeeded
FAIL
FAIL	os	0.341s

[bradfitz]

/cc @ianlancetaylor

[laboger]

Kind of odd that this passed the buildbots but fails everywhere else?

[mundaym]

@laboger I could be wrong but I think the trybots only check that the distribution compiles when targeting ppc64(le?), I don't think they actually run the tests on ppc64x. Does it fail for you locally?

[bradfitz]

Correct. Trybots (pre-submit tests) only compile ppc64x but don't run the tests. Post-submit builds run the tests on ppc64x hardware. We need lots of hardware to support trybots.

[ianlancetaylor]

What does getconf PIPE_BUF /tmp print on your system?

[bradfitz]

$ gomote create linux-ppc64-buildlet
user-bradfitz-linux-ppc64-buildlet-0
$ gomote run -system user-bradfitz-linux-ppc64-buildlet-0 getconf PIPE_BUF /tmp
4096

$ gomote create linux-ppc64le-buildlet
user-bradfitz-linux-ppc64le-buildlet-0
$ gomote run -system user-bradfitz-linux-ppc64le-buildlet-0 getconf PIPE_BUF /tmp                                                                                                              
4096

[ianlancetaylor]

OK, that is just weird. This should not be processor dependent.

[gopherbot]

CL https://golang.org/cl/41823 mentions this issue.