From: Pavel Machek <pavel@ucw.cz>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Kevin Hilman <khilman@kernel.org>,
linux-pm@vger.kernel.org, Len Brown <len.brown@intel.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Lina Iyer <lina.iyer@linaro.org>,
Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Subject: Re: [PATCH 1/2] PM / Domains: Don't measure ->start|stop() latency in system PM callbacks
Date: Wed, 21 Oct 2015 12:31:26 +0200 [thread overview]
Message-ID: <20151021103126.GA16738@amd> (raw)
In-Reply-To: <1444921326-22574-1-git-send-email-ulf.hansson@linaro.org>
On Thu 2015-10-15 17:02:06, Ulf Hansson wrote:
> Measure latency does by itself contribute to an increased latency, thus we
> should avoid it when it isn't needed.
>
> Genpd measures latencies in the system PM phase for the ->start|stop()
> callbacks and is thus affecting the system PM suspend/resume time.
> Moreover these latencies are validated only at runtime PM suspend/resume.
>
> To this reasoning, let's decide to leave these measurements out of the
> system PM phase. There should be plenty of occasions during runtime PM to
> perform these measurements anyway.
How much latency does the latency measure cause? Something like 0.000
msec?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2015-10-21 10:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-15 15:02 [PATCH 1/2] PM / Domains: Don't measure ->start|stop() latency in system PM callbacks Ulf Hansson
2015-10-15 20:39 ` Lina Iyer
2015-10-21 10:31 ` Pavel Machek [this message]
2015-10-21 12:47 ` Ulf Hansson
2015-10-21 23:47 ` Rafael J. Wysocki
2015-10-23 18:48 ` Kevin Hilman
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