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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: viresh.kumar@linaro.org, svaidy@linux.vnet.ibm.com,
	ego@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpufreq: governor: Be friendly towards latency-sensitive bursty workloads
Date: Tue, 27 May 2014 01:27:54 +0200	[thread overview]
Message-ID: <2902116.OdbNv5KQzQ@vostro.rjw.lan> (raw)
In-Reply-To: <20140526205337.1100.55275.stgit@srivatsabhat.in.ibm.com>

Hi Srivatsa,

On Tuesday, May 27, 2014 02:23:38 AM Srivatsa S. Bhat wrote:
> Cpufreq governors like the ondemand governor calculate the load on the CPU
> periodically by employing deferrable timers. A deferrable timer won't fire
> if the CPU is completely idle (and there are no other timers to be run), in
> order to avoid unnecessary wakeups and thus save CPU power.
> 
> However, the load calculation logic is agnostic to all this, and this can
> lead to the problem described below.

This is subtle enough that I need some more time to chew on it, but since the
merge window is coming, I'm not sure when that's going to happen honestly.

Rafael


  reply	other threads:[~2014-05-26 23:10 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-26 20:53 Srivatsa S. Bhat
2014-05-26 23:27 ` Rafael J. Wysocki [this message]
2014-05-27  3:15   ` Srivatsa S. Bhat
2014-06-02  7:33 ` Gautham R Shenoy
2014-06-02  8:15   ` Srivatsa S. Bhat
2014-06-03  5:16     ` Gautham R Shenoy
2014-06-03  5:49       ` Srivatsa S. Bhat
2014-06-03  8:18 ` Viresh Kumar
2014-06-03  9:32   ` Srivatsa S. Bhat
2014-06-03  9:39     ` Viresh Kumar
2014-06-03 10:04       ` Srivatsa S. Bhat
2014-06-03 10:08         ` Viresh Kumar
2014-06-03 10:13           ` Srivatsa S. Bhat
2014-06-03 10:16             ` Viresh Kumar
2014-06-03 10:16               ` Srivatsa S. Bhat
2014-06-07  9:55 ` Pavel Machek
2014-06-07 12:35   ` Srivatsa S. Bhat

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