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From: Mel Gorman <mgorman@techsingularity.net>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Phil Auld <pauld@redhat.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] sched/fair: Track possibly overloaded domains and abort a scan if necessary
Date: Fri, 20 Mar 2020 16:44:32 +0000	[thread overview]
Message-ID: <20200320164432.GE3818@techsingularity.net> (raw)
In-Reply-To: <CAKfTPtAUuO1Jp6P73gAiP+g5iLTx16UeBgBjm_5zjFxwiBD9=Q@mail.gmail.com>

On Fri, Mar 20, 2020 at 04:48:39PM +0100, Vincent Guittot wrote:
> > ---
> >  include/linux/sched/topology.h |  1 +
> >  kernel/sched/fair.c            | 65 +++++++++++++++++++++++++++++++++++++++---
> >  kernel/sched/features.h        |  3 ++
> >  3 files changed, 65 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
> > index af9319e4cfb9..76ec7a54f57b 100644
> > --- a/include/linux/sched/topology.h
> > +++ b/include/linux/sched/topology.h
> > @@ -66,6 +66,7 @@ struct sched_domain_shared {
> >         atomic_t        ref;
> >         atomic_t        nr_busy_cpus;
> >         int             has_idle_cores;
> > +       int             is_overloaded;
> 
> Can't nr_busy_cpus compared to sd->span_weight give you similar status  ?
> 

It's connected to nohz balancing and I didn't see how I could use that
for detecting overload. Also, I don't think it ever can be larger than
the sd weight and overload is based on the number of running tasks being
greater than the number of available CPUs. Did I miss something obvious?

-- 
Mel Gorman
SUSE Labs

  reply	other threads:[~2020-03-20 16:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-20 15:12 [PATCH 0/4] Throttle select_idle_sibling when a target domain is overloaded Mel Gorman
2020-03-20 15:12 ` [PATCH 1/4] sched/fair: Track efficiency of select_idle_sibling Mel Gorman
2020-03-23 13:30   ` Valentin Schneider
2020-03-23 13:55     ` Mel Gorman
2020-03-20 15:12 ` [PATCH 2/4] sched/fair: Track efficiency of task recent_used_cpu Mel Gorman
2020-03-23 13:30   ` Valentin Schneider
2020-03-20 15:12 ` [PATCH 3/4] sched/fair: Clear SMT siblings after determining the core is not idle Mel Gorman
2020-03-23 13:31   ` Valentin Schneider
2020-03-20 15:12 ` [PATCH 4/4] sched/fair: Track possibly overloaded domains and abort a scan if necessary Mel Gorman
2020-03-20 15:48   ` Vincent Guittot
2020-03-20 16:44     ` Mel Gorman [this message]
2020-03-20 16:54       ` Vincent Guittot
2020-03-20 17:43         ` Mel Gorman
2020-03-24 10:35           ` Vincent Guittot
2020-03-24 11:23             ` Mel Gorman
2020-04-02  7:59   ` [sched/fair] 15e7470dfc: hackbench.throughput 11.2% improvement kernel test robot

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