Re: [PATCH v3 0/2] sched: Minor changes for rd->overload access

From: Ingo Molnar
Date: Tue Mar 26 2024 - 04:00:49 EST



* Shrikanth Hegde <sshegde@xxxxxxxxxxxxx> wrote:

>
>
> On 3/25/24 4:06 PM, Ingo Molnar wrote:
> >
> > * Shrikanth Hegde <sshegde@xxxxxxxxxxxxx> wrote:
> >
> >> v2 -> v3:
> >> - Wrapped check for value change inside ser_rd_overload_status
> >> as suggested by Qais.
> >> - Added reviewed-by tags.
> >>
> >> v1 -> v2:
> >> - dropped Fixes tag.
> >> - Added one of the perf probes in the changelog for reference.
> >> - Added reviewed-by tags.
> >>
> >> tl;dr
> >> When running workloads in large systems, it was observed that access to
> >> rd->overload was taking time. It would be better to check the value
> >> before updating since value changes less often. Patch 1/2 does that.
> >> With patch updates happen only if necessary. CPU Bus traffic reduced a
> >> bit. No significant gains in workload performance.
> >
> > Could you please post this against the latest scheduler tree, ie. tip:sched/core?
> >
> > Thanks,
> >
> > Ingo
>
> Hi Ingo. I had mentioned the same in cover letter. Sorry if I didn't
> mention it in the correct place.
>
> *These patches depend on below to be applied first*
> https://lore.kernel.org/all/20240307085725.444486-1-sshegde@xxxxxxxxxxxxx/
>
> After that the above patch would apply.

OK, I missed that, but I don't really like patch #3 of that other series,
so we'll need to address that first.

Thanks,

Ingo