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Message-ID: <d211d4dedd79330412e71a8b9b4b599cfe0fc80c.camel@linux.intel.com>
Date: Mon, 26 Jun 2023 12:52:59 -0700
From: Tim Chen <tim.c.chen@...ux.intel.com>
To: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
Ionela Voinescu <ionela.voinescu@....com>
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Ricardo Neri <ricardo.neri@...el.com>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Ben Segall <bsegall@...gle.com>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Len Brown <len.brown@...el.com>, Mel Gorman <mgorman@...e.de>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Steven Rostedt <rostedt@...dmis.org>,
Valentin Schneider <vschneid@...hat.com>,
Lukasz Luba <lukasz.luba@....com>,
Zhao Liu <zhao1.liu@...el.com>,
"Yuan, Perry" <Perry.Yuan@....com>, x86@...nel.org,
"Joel Fernandes (Google)" <joel@...lfernandes.org>,
linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
"Tim C . Chen" <tim.c.chen@...el.com>,
Zhao Liu <zhao1.liu@...ux.intel.com>
Subject: Re: [PATCH v4 06/24] sched/fair: Collect load-balancing stats for
IPC classes
> >
> > nit: the comment is unnecessary, and a bit misleading, IMO.
> >
> > The comment says "This group will not be selected." but the only way to
> > guarantee that here is to reset the sum_score to 0 when you find an
> > invalid score, which I don't believe is your intention.
>
> You raise an interesting point. We will call this function for each rq
> in the sched group. Thus, if we encounter an error, the scores would be
> incomplete. Therefore, I think that the scores should be discarded and
> reset to 0 so that they are not used, IMO.
Since we still have other rqs to loop through, reset to 0 here does
not guarantee that it will stay that way at the end of the loop when
the sum could still be added to. May need a special value like -EINVAL
and make the score a "long" to mark such case.
Tim
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