runtime: yield instead of sleeping in runqgrab on OpenBSD
OpenBSD has a coarse sleep granularity that rounds up to 10 ms
increments. This can cause significant STW delays, among other issues.
As far as I can tell, there's only 1 tightly timed sleep without an
explicit wakeup for which this actually matters.
Fixes #52475.
Change-Id: Ic69fc11096ddbbafd79b2dcdf3f912fde242db24
Reviewed-on: https://go-review.googlesource.com/c/go/+/401638
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index b281d9f..96d44ef 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -5904,10 +5904,10 @@
// between different Ps.
// A sync chan send/recv takes ~50ns as of time of
// writing, so 3us gives ~50x overshoot.
- if GOOS != "windows" {
+ if GOOS != "windows" && GOOS != "openbsd" {
usleep(3)
} else {
- // On windows system timer granularity is
+ // On some platforms system timer granularity is
// 1-15ms, which is way too much for this
// optimization. So just yield.
osyield()
