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Message-ID: <1ac1f37ecccb23ec6abe07ef6a95fc1d61921436.camel@linux.intel.com>
Subject: Re: [PATCH 3/6] sched/fair: Fix busiest group selection for asym
 groups
From:   Tim Chen <tim.c.chen@linux.intel.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Ricardo Neri <ricardo.neri@intel.com>,
        "Ravi V . Shankar" <ravi.v.shankar@intel.com>,
        Ben Segall <bsegall@google.com>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Len Brown <len.brown@intel.com>, Mel Gorman <mgorman@suse.de>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Valentin Schneider <vschneid@redhat.com>,
        Ionela Voinescu <ionela.voinescu@arm.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org,
        Shrikanth Hegde <sshegde@linux.vnet.ibm.com>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
        naveen.n.rao@linux.vnet.ibm.com,
        Yicong Yang <yangyicong@hisilicon.com>,
        Barry Song <v-songbaohua@oppo.com>,
        Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Date:   Fri, 05 May 2023 15:36:47 -0700
In-Reply-To: <20230505131903.GP83892@hirez.programming.kicks-ass.net>
References: <cover.1683156492.git.tim.c.chen@linux.intel.com>
         <2e2e6844fb3ed28594d86c5e45295df7c4335c08.1683156492.git.tim.c.chen@linux.intel.com>
         <20230505131903.GP83892@hirez.programming.kicks-ass.net>
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On Fri, 2023-05-05 at 15:19 +0200, Peter Zijlstra wrote:
>=20
> > =20
> >  	case group_has_spare:
> > +		/*
> > +		 * Do not pick sg with SMT CPUs over sg with pure CPUs,
> > +		 * as we do not want to pull task off half empty SMT core
> > +		 * and make the core idle.
> > +		 */
>=20
> Comment says what the code does; not why.

Good point, will make the comment better.

>=20
> > +		if (asymmetric_groups(sds->busiest, sg)) {
> > +			if (sds->busiest->flags & SD_SHARE_CPUCAPACITY)
> > +				return true;
> > +			else
> > +				return false;
>=20
> 			return (sds->busiest->flags & SD_SHARE_CPUCAPACITY)
> > +		}
>=20
> Also, should this not be part of the previous patch?

Sure, I can merge it with the previous patch.

Tim