From windows-amd64 builder:
http://build.golang.org/log/386a00b3ac3147a7f33d114bc3af3d494b87a649

--- FAIL: TestGoroutineSwitch (0.23 seconds)
    pprof_test.go:240: found profile entry for runtime.gogo:
        0x42b6e2 c:/go/src/pkg/runtime/asm_amd64.s:153
        0x415060 c:/go/src/pkg/runtime/proc.c:1409
        0x4168a1 c:/go/src/pkg/runtime/proc.c:1996
        0x443a48 c:/gobuilder/windows-amd64-993231085fbf/go/src/pkg/runtime/pprof/pprof_test.go:209
        0x43cb32 c:/go/src/pkg/testing/testing.go:423
        0x415120 c:/go/src/pkg/runtime/proc.c:1430
FAIL
FAIL    runtime/pprof   11.432s

I can reproduce this by running

for /l %x in (1, 1, 50) do go test -v -run=TestGoroutineSwitch -cpu=1,2,4

I get maybe 4 (on average) failures for those 50 runs. All failures are on
windows/amd64, no windows/386 failures.

Alex