Re: Poor condvar performance

Ingo Molnar <[email protected]> Wed, 26 Nov 2003 23:39:03 +0100 (CET)
Newsgroups gmane.comp.lib.phil
Message-ID <Pine.LNX.4.58.0311262337500.4829@earth>
On Wed, 26 Nov 2003, Luke Elliott wrote:

> I'm actually using pthread_cond_broadcast() as I may have multiple
> consumer threads. However, in this case I do only have one thread. I've
> just tried using pthread_cond_signal() and I see the same behaviour;
> i.e. very high context switches / sec with the vanilla futex.c and
> sched.c, and sensible numbers with the wake_up_all() hacks.

it turns out that the requeue implementation had to be turned off in the
CVS a few weeks ago - so the behavior you see is in fact expected (and
suboptimal, no doubt). I think Ulrich will be able to tell more how to
enable it again.

	Ingo