From: Srikar Dronamraju <srikar@linux.ibm.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Ben Segall <bsegall@google.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Ingo Molnar <mingo@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Mel Gorman <mgorman@suse.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Valentin Schneider <vschneid@redhat.com>
Subject: Re: [PATCH v2 2/2] powerpc/smp: Disable steal from updating CPU capacity
Date: Mon, 1 Dec 2025 17:45:37 +0530 [thread overview]
Message-ID: <aS2G6XDdGse5RYw5@linux.ibm.com> (raw)
In-Reply-To: <CAKfTPtDtfy7=rb6rPVMAk1+Bq4w=+opiWuo_Y+3dy3me--6KsA@mail.gmail.com>
* Vincent Guittot <vincent.guittot@linaro.org> [2025-11-03 09:46:26]:
> Hi Sikar,
>
> On Wed, 29 Oct 2025 at 09:32, Srikar Dronamraju <srikar@linux.ibm.com> wrote:
> >
> > * Vincent Guittot <vincent.guittot@linaro.org> [2025-10-29 08:43:34]:
> >
> > > Hi Srikar,
> > >
> > > On Wed, 29 Oct 2025 at 07:09, Srikar Dronamraju <srikar@linux.ibm.com> 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
prev parent reply other threads:[~2025-12-01 12:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 6:07 [PATCH v2 1/2] sched/core: Option if steal should update CPU capacity Srikar Dronamraju
2025-10-29 6:07 ` [PATCH v2 2/2] powerpc/smp: Disable steal from updating " Srikar Dronamraju
2025-10-29 7:43 ` Vincent Guittot
2025-10-29 8:31 ` Srikar Dronamraju
2025-11-03 8:46 ` Vincent Guittot
2025-11-06 5:22 ` Srikar Dronamraju
2025-12-01 12:15 ` Srikar Dronamraju [this message]
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