From: Peter Zijlstra <peterz@infradead.org>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
mingo@redhat.com, juri.lelli@redhat.com,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de,
linux-kernel@vger.kernel.org, iwtbavbm@gmail.com
Subject: Re: [PATCH v2] sched/fair: fix nohz next idle balance
Date: Thu, 11 Jun 2020 16:28:06 +0200 [thread overview]
Message-ID: <20200611142806.GJ2531@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <jhjpna53d50.mognet@arm.com>
On Thu, Jun 11, 2020 at 03:12:11PM +0100, Valentin Schneider wrote:
>
> On 09/06/20 13:37, Vincent Guittot wrote:
> > With commit:
> > 'b7031a02ec75 ("sched/fair: Add NOHZ_STATS_KICK")'
> > rebalance_domains of the local cfs_rq happens before others idle cpus have
> > updated nohz.next_balance and its value is overwritten.
> >
> > Move the update of nohz.next_balance for other idles cpus before balancing
> > and updating the next_balance of local cfs_rq.
> >
> > Also, the nohz.next_balance is now updated only if all idle cpus got a
> > chance to rebalance their domains and the idle balance has not been aborted
> > because of new activities on the CPU. In case of need_resched, the idle
> > load balance will be kick the next jiffie in order to address remaining
> > ilb.
> >
> > Reported-by: Peng Liu <iwtbavbm@gmail.com>
> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
>
> FWIW:
> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
>
> Do we want a Fixes: tag for this? I'm thinking
> b7031a02ec75 ("sched/fair: Add NOHZ_STATS_KICK")
Done, thanks!
next prev parent reply other threads:[~2020-06-11 14:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-09 12:37 [PATCH v2] sched/fair: fix nohz next idle balance Vincent Guittot
2020-06-10 12:49 ` Peter Zijlstra
2020-06-11 14:12 ` Valentin Schneider
2020-06-11 14:28 ` Peter Zijlstra [this message]
2020-06-11 14:43 ` Mel Gorman
2020-06-16 12:21 ` [tip: sched/core] sched/fair: Fix NOHZ " tip-bot2 for Vincent Guittot
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