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Date:   Fri, 27 Sep 2019 15:53:00 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Parth Shah <parth@linux.ibm.com>
Cc:     Valentin Schneider <valentin.schneider@arm.com>,
        Patrick Bellasi <patrick.bellasi@arm.com>,
        linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        subhra mazumdar <subhra.mazumdar@oracle.com>,
        tim.c.chen@linux.intel.com, mingo@redhat.com,
        morten.rasmussen@arm.com, dietmar.eggemann@arm.com, pjt@google.com,
        vincent.guittot@linaro.org, quentin.perret@arm.com,
        dhaval.giani@oracle.com, daniel.lezcano@linaro.org, tj@kernel.org,
        rafael.j.wysocki@intel.com, qais.yousef@arm.com,
        Patrick Bellasi <patrick.bellasi@matbug.net>
Subject: Re: Usecases for the per-task latency-nice attribute
Message-ID: <20190927135259.GB3557@bug>
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Hi!

> > I don't want to start a bikeshedding session here, but I agree with Parth
> > on the interpretation of the values.
> > 
> > I've always read niceness values as
> > -20 (least nice to the system / other processes)
> > +19 (most nice to the system / other processes)
> > 
> > So following this trend I'd see for latency-nice:
> 
> 
> So jotting down separately, in case if we think to have "latency-nice"
> terminology, then we might need to select one of the 2 interpretation:
> 
> 1).
> > -20 (least nice to latency, i.e. sacrifice latency for throughput)
> > +19 (most nice to latency, i.e. sacrifice throughput for latency)
> > 
> 
> 2).
> -20 (least nice to other task in terms of sacrificing latency, i.e.
> latency-sensitive)
> +19 (most nice to other tasks in terms of sacrificing latency, i.e.
> latency-forgoing)

For the record, interpretation 2 makes sense to me.

									Pavel

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