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From: Paul Turner <pjt@google.com>
Date: Mon, 6 May 2013 03:00:23 -0700
Message-ID: <CAPM31RLKf=3WnUmnXartb21HmdCFeimvtxgL_A3sjC8=UvC-Kw@mail.gmail.com>
Subject: Re: [PATCH v5 7/7] sched: consider runnable load average in effective_load
To: Alex Shi <alex.shi@intel.com>
Cc: Michael Wang <wangyun@linux.vnet.ibm.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Borislav Petkov <bp@alien8.de>, Namhyung Kim <namhyung@kernel.org>,
        Mike Galbraith <efault@gmx.de>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>
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On Mon, May 6, 2013 at 2:35 AM, Alex Shi <alex.shi@intel.com> wrote:
> On 05/06/2013 05:06 PM, Paul Turner wrote:
>> I don't think this is a good idea:
>>
>> The problem with not using the instantaneous weight here is that you
>> potentially penalize the latency of interactive tasks (similarly,
>> potentially important background threads -- e.g. garbage collection).
>>
>> Counter-intuitively we actually want such tasks on the least loaded
>> cpus to minimize their latency.  If the load they contribute ever
>> becomes more substantial we trust that periodic balance will start
>> taking notice of them.
>
> Sounds reasonable. Many thanks for your input, Paul!
>
> So, will use the seconds try. :)

Sorry -- not sure what you mean here.  I'm suggesting leaving
effective_load() unchanged.
>>
>> [ This is similar to why we have to use the instantaneous weight in
>> calc_cfs_shares. ]
>>
>
>
> --
> Thanks
>     Alex
--
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