Subject: Re: [PATCH v2 2/2] powerpc/smp: Disable steal from updating CPU capacity

From: Srikar Dronamraju <[email-masked]>
Date: Mon, 1 Dec 2025 17:45:37 +0530

* Vincent Guittot <[email-masked]> [2025-11-03 09:46:26]:

> Hi Sikar,
> 
> On Wed, 29 Oct 2025 at 09:32, Srikar Dronamraju <[email-masked]> wrote:
> >
> > * Vincent Guittot <[email-masked]> [2025-10-29 08:43:34]:
> >
> > > Hi Srikar,
> > >
> > > On Wed, 29 Oct 2025 at 07:09, Srikar Dronamraju <[email-masked]> wrote:
> > > >
> > > > In a shared LPAR with SMT enabled, it has been observed that when a CPU
> > > > experiences steal time, it can trigger task migrations between sibling
> > > > CPUs. The idle CPU pulls a runnable task from its sibling that is
> > > > impacted by steal, making the previously busy CPU go idle. This reversal
> > >
> > > IIUC, the migration is triggered by the reduced capacity case when
> > > there is 1 task on the CPU

Hi Peter, Vincent

Do you have any more inputs on this?
If not can this pulled into the scheduler code.

--
Thanks and Regards
Srikar Dronamraju