Re: [PATCH] sched/core: An optimization of pick_next_task() not sure

[Josh Don]

On Mon, Aug 16, 2021 at 11:53 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Mon, Aug 16, 2021 at 11:44:01PM +0800, Tao Zhou wrote:
> > When find a new candidate max, wipe the stale and start over.
> > Goto again: and use the new max to loop to pick the the task.
> >
> > Here first want to get the max of the core and use this new
> > max to loop once to pick the task on each thread.
> >
> > Not sure this is an optimization and just stop here a little
> > and move on..
> >
>
> Did you find this retry was an issue on your workload? Or was this from
> reading the source?

I would be surprised if this made a noticeable difference on SMT2, but
I could certainly see how this would help with larger SMT
configurations where we have more opportunities to invalidate the
other siblings.