From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek 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 Message-ID: <20151021103126.GA16738@amd> References: <1444921326-22574-1-git-send-email-ulf.hansson@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:40281 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753750AbbJUKba (ORCPT ); Wed, 21 Oct 2015 06:31:30 -0400 Content-Disposition: inline In-Reply-To: <1444921326-22574-1-git-send-email-ulf.hansson@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Ulf Hansson Cc: "Rafael J. Wysocki" , Kevin Hilman , linux-pm@vger.kernel.org, Len Brown , Geert Uytterhoeven , Lina Iyer , Krzysztof Kozlowski 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