Re: [PATCH v3 1/3] sched/fair: Move checking for nohz cpus after time check

[Shrikanth Hegde]

Hi Peter. Thanks for going through.

On 1/8/26 6:14 PM, Peter Zijlstra wrote:
> On Wed, Jan 07, 2026 at 12:21:23PM +0530, Shrikanth Hegde wrote:
> > NOHZ idle load balancer is kicked off only after time check. So move
> > the atomic read after the time check to access it only when needed.
> >
> > When there are no idle CPUs(100% busy), even if the flag gets set to
> > NOHZ_STATS_KICK | NOHZ_NEXT_KICK, find_new_ilb will fail and
> > there will be no NOHZ idle balance. The current behaviour is retained.
> >
> > Note: This patch doesn't solve any cacheline overheads. No improvement
> > in performance apart from saving a few cycles of atomic_read.
>
> Note that atomic_read() == READ_ONCE() is just a regular load, but sure.

Cool. thanks. Let me keep it in the series then.