From: Mel Gorman <mgorman@techsingularity.net>
To: Rik van Riel <riel@surriel.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
pauld@redhat.com, valentin.schneider@arm.com,
srikar@linux.vnet.ibm.com, quentin.perret@arm.com,
dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com,
hdanton@sina.com, parth@linux.ibm.com,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched, fair: Allow a small load imbalance between low utilisation SD_NUMA domains v3
Date: Mon, 6 Jan 2020 16:33:03 +0000 [thread overview]
Message-ID: <20200106163303.GC3466@techsingularity.net> (raw)
In-Reply-To: <04033a63f11a9c59ebd2b099355915e4e889b772.camel@surriel.com>
On Mon, Jan 06, 2020 at 10:47:18AM -0500, Rik van Riel wrote:
> > + imbalance_adj = (100 / (env->sd->imbalance_pct
> > - 100)) - 1;
> > +
> > + /*
> > + * Allow small imbalances when the busiest
> > group has
> > + * low utilisation.
> > + */
> > + imbalance_max = imbalance_adj << 1;
> > + if (busiest->sum_nr_running < imbalance_max)
> > + env->imbalance -= min(env->imbalance,
> > imbalance_adj);
> > + }
> > +
>
> Wait, so imbalance_max is a function only of
> env->sd->imbalance_pct, and it gets compared
> against busiest->sum_nr_running, which is related
> to the number of CPUs in the node?
>
It's not directly related to the number of CPUs in the node. Are you
thinking of busiest->group_weight?
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2020-01-06 16:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-06 14:42 [PATCH] sched, fair: Allow a small load imbalance between low utilisation SD_NUMA domains v3 Mel Gorman
2020-01-06 15:47 ` Rik van Riel
2020-01-06 16:33 ` Mel Gorman [this message]
2020-01-06 16:44 ` Rik van Riel
2020-01-06 17:19 ` Mel Gorman
[not found] ` <20200107015111.4836-1-hdanton@sina.com>
2020-01-07 8:44 ` Vincent Guittot
2020-01-07 9:12 ` Mel Gorman
2020-01-07 9:43 ` Vincent Guittot
2020-01-07 10:16 ` Mel Gorman
2020-01-08 15:49 ` Valentin Schneider
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