Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <8333da418828569495f3b92919e6980a5dac0295.camel@linux.intel.com>
Subject: Re: [Patch v3 3/6] sched/fair: Implement prefer sibling imbalance
 calculation between asymmetric groups
From:   Tim Chen <tim.c.chen@linux.intel.com>
To:     Shrikanth Hegde <sshegde@linux.vnet.ibm.com>,
        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,
        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>,
        Chen Yu <yu.c.chen@intel.com>, Hillf Danton <hdanton@sina.com>,
        Tobias Huschle <huschle@linux.ibm.com>
Date:   Fri, 14 Jul 2023 16:23:04 -0700
In-Reply-To: <f9a51b01bdddd739faedb196156e69fbad41f9f5.camel@linux.intel.com>
References: <cover.1688770494.git.tim.c.chen@linux.intel.com>
         <4eacbaa236e680687dae2958378a6173654113df.1688770494.git.tim.c.chen@linux.intel.com>
         <c5a49136-3549-badd-ec8f-3de4e7bb7b7d@linux.vnet.ibm.com>
         <f9a51b01bdddd739faedb196156e69fbad41f9f5.camel@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) 
MIME-Version: 1.0
Precedence: bulk

On Fri, 2023-07-14 at 13:44 -0700, Tim Chen wrote:
> > >=20
> > > +static inline long sibling_imbalance(struct lb_env *env,
> > > +				    struct sd_lb_stats *sds,
> > > +				    struct sg_lb_stats *busiest,
> > > +				    struct sg_lb_stats *local)
> > > +{
> > > +	int ncores_busiest, ncores_local;
> > > +	long imbalance;
> >=20
> > can imbalance be unsigned int or unsigned long? as sum_nr_running is un=
signed int.
>=20
> It could be made unsigned long.=20
>=20
>=20
Though in theory the imbalance can be both positive or negative. We are
considering only positive imbalance here as we only pull task to local grou=
p
and do not push task from local group.

Tim