linux-kernel - Re: [PATCH v4 6/6] sched/fair: Consider SMT in ASYM

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Message-ID: <20210827194503.GB14720@ranerica-svr.sc.intel.com>
Date:   Fri, 27 Aug 2021 12:45:03 -0700
From:   Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Len Brown <len.brown@...el.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Aubrey Li <aubrey.li@...ux.intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@...el.com>,
        Ricardo Neri <ricardo.neri@...el.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Quentin Perret <qperret@...gle.com>,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        linuxppc-dev@...ts.ozlabs.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Aubrey Li <aubrey.li@...el.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>
Subject: Re: [PATCH v4 6/6] sched/fair: Consider SMT in ASYM_PACKING load
 balance

On Fri, Aug 27, 2021 at 12:13:42PM +0200, Vincent Guittot wrote:
> On Tue, 10 Aug 2021 at 16:41, Ricardo Neri
> <ricardo.neri-calderon@...ux.intel.com> wrote:
> > @@ -9540,6 +9629,12 @@ static struct rq *find_busiest_queue(struct lb_env *env,
> >                     nr_running == 1)
> >                         continue;
> >
> > +               /* Make sure we only pull tasks from a CPU of lower priority */
> > +               if ((env->sd->flags & SD_ASYM_PACKING) &&
> > +                   sched_asym_prefer(i, env->dst_cpu) &&
> > +                   nr_running == 1)
> > +                       continue;
> 
> This really looks similar to the test above for SD_ASYM_CPUCAPACITY.
> More generally speaking SD_ASYM_PACKING and SD_ASYM_CPUCAPACITY share
> a lot of common policy and I wonder if at some point we could not
> merge their behavior in LB

I would like to confirm with you that you are not expecting this merge
as part of this series, right?

Thanks and BR,
Ricardo