Re: [PATCH] locking/ww_mutex: Replace cpu_relax with cond_resched for tests

From: Chris Wilson
Date: Tue Feb 28 2017 - 04:59:18 EST


On Tue, Feb 28, 2017 at 10:48:53AM +0100, Peter Zijlstra wrote:
> On Tue, Feb 28, 2017 at 09:40:11AM +0000, Chris Wilson wrote:
> > When busy-spinning on a ww_mutex_trylock(), we depend upon the other
> > thread advancing and releasing the lock. This can not happen on a single
> > CPU unless we relinquish it.
>
> Thanks, do you have any clue about those other ww-mutex test fails? So
> far I've not had much luck poking at them.

Not yet, they didn't seem quite so self-explanatory as this trace :(
-Chris

--
Chris Wilson, Intel Open Source Technology Centre