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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Philipp Miedl <philipp.miedl@tik.ee.ethz.ch>
Cc: alex@digriz.org.uk, jun.nakajima@intel.com,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>
Subject: Re: Delayed acpi frequency governor call
Date: Wed, 25 Jan 2017 08:53:41 +0530	[thread overview]
Message-ID: <20170125032341.GC20040@vireshk-i7> (raw)
In-Reply-To: <2f9b2f69-8b93-c77a-a09f-540240fecf1e@tik.ee.ethz.ch>

On 24-01-17, 15:49, Philipp Miedl wrote:
> Can you please describe how things changed from version 4.4 to 4.9 - I'm not
> sure if I understand correctly.
> Before 4.7 the governor was just running as a kernel process and triggered
> by the (free running) timers and
> now its hooked with the scheduler. So the scheduler ensures that the
> governor work is not delayed?!

Now the cpufreq callbacks gets called from within the scheduler every few
milliseconds. And once we have crossed the sampling-rate time, we reevaluate the
frequency. Though ondemand/conservative governors still used workqueue until
very recently for most of the platforms. Recently it is replaced by a RT thread.

-- 
viresh

  reply	other threads:[~2017-01-25  3:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <c8ee7078-ad5a-0a23-66ae-620c507300e5@tik.ee.ethz.ch>
2017-01-20 10:07 ` Delayed acpi frequency governor call Viresh Kumar
2017-01-20 15:27   ` Philipp Miedl
2017-01-23 10:11     ` Viresh Kumar
2017-01-23 14:24       ` Philipp Miedl
2017-01-24  4:22         ` Viresh Kumar
2017-01-24 14:49           ` Philipp Miedl
2017-01-25  3:23             ` Viresh Kumar [this message]
2017-01-25  9:48               ` Philipp Miedl

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