Fine-grained locking for POSIX local sockets (UNIX domain
kris at obsecurity.org
Tue May 9 01:11:16 UTC 2006
On Mon, May 08, 2006 at 08:43:28PM -0400, Kris Kennaway wrote:
> On Mon, May 08, 2006 at 02:52:07AM -0400, Kris Kennaway wrote:
> > OK, David's patch fixes the umtx thundering herd (and seems to give a
> > 4-6% boost). I also fixed a thundering herd in FILEDESC_UNLOCK (which
> > was also waking up 2-7 CPUs at once about 30% of the time) by doing
> > s/wakeup/wakeup_one/. This did not seem to give a performance impact
> > on this test though.
> Turning down kern.hz from 1000 to 100 also made a big difference on 12
> CPUs (+6.1%).
> Note also that the system is no less than 40% idle during the runs (at
> any load), so the bottlenecks are serious.
top -H shows the threads mostly in umtx state.
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