Re: [PATCH 5/5] sched/rt: Optimize find_lowest_rq() to select a cache hot cpu

Steven Rostedt
2015-01-27T14:56:31Z

On Tue, 27 Jan 2015 15:21:36 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, Jan 19, 2015 at 04:49:40AM +0000, Xunlei Pang wrote:
> > In find_lowest_rq(), if we can't find a wake_affine cpu from
> > sched_domain, then we can actually determine a cache hot cpu
> > instead of simply calling "cpumask_any(lowest_mask)" which
> > always returns the first cpu in the mask.
> >
> > So, we can determine the cache hot cpu during the interation of
> > sched_domain() in passing.
>
> Steve, I'm not getting this. Why are we using WAKE_AFFINE here?
>

It originated from Gregory Haskins topology patches. See
6e1254d2c41215da27025add8900ed187bca121d

-- Steve