Re: [PATCH] sched: consider WF_SYNC to find idle siblings

From: Andrei Vagin
Date: Wed Nov 16 2022 - 13:53:15 EST


Hello Mel and Prateek,

Thank you both for running tests and publishing results here.

On Wed, Nov 16, 2022 at 2:57 AM Mel Gorman <mgorman@xxxxxxx> wrote:
<snip>
>
> This is not too surprising as UDP_STREAM is blasting packets so there are
> wakeups but the waker is not going to sleep immediately. So yeah, there are
> cases where the patch helps but when it hurts, it can hurt a lot. The patch
> certainly demonstrates that there is room for improvement on how WF_SYNC is
> treated but as it stands, it would start a game of apply/revert ping-pong
> as different bisections showed the patch caused one set of problems and
> the revert caused another.

I agree with these conclusions. The situation is more complex than how
I saw it initially.

Thanks,
Andrei