code review 134360043: runtime: increase windows prof thread priority sooner

runtime: increase windows prof thread priority sooner

If system is busy burning cpu, it takes long time (about 300ms on
windows builders) to adjust prof thread priority. Once adjusted, prof
thread runs ahead of everyone else, but due to initial slowness, it
does not capture prof snapshots until start-up period is completed.

Change prof thread priority sooner, so it can start captures straight
away.

[brainman, 2014-09-03 02:46:05]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[dvyukov, 2014-09-03 03:33:39]

LGTM
I would even do it both places. The thread that calls setcpuprofilerate can
exhaust its quant between thread creation and setthreadpriority...

[brainman, 2014-09-03 04:17:11]

*** Submitted as https://code.google.com/p/go/source/detail?r=2008238cdc04 ***

runtime: increase windows prof thread priority sooner

If system is busy burning cpu, it takes long time (about 300ms on
windows builders) to adjust prof thread priority. Once adjusted, prof
thread runs ahead of everyone else, but due to initial slowness, it
does not capture prof snapshots until start-up period is completed.

Change prof thread priority sooner, so it can start captures straight
away.

LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://codereview.appspot.com/134360043

[brainman, 2014-09-03 04:17:35]

On 2014/09/03 03:33:39, dvyukov wrote:
> ...
> I would even do it both places. The thread that calls setcpuprofilerate can
> exhaust its quant between thread creation and setthreadpriority...

Done.

Alex

[gobot, 2014-09-03 04:20:54]

This CL appears to have broken the linux-amd64-race-temp builder.
See http://build.golang.org/log/c0ee8f3e5c4d7b978acf229b2e6bff20f16271d3