From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966078AbXHaSWe (ORCPT ); Fri, 31 Aug 2007 14:22:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965826AbXHaSWY (ORCPT ); Fri, 31 Aug 2007 14:22:24 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:45955 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964994AbXHaSWX (ORCPT ); Fri, 31 Aug 2007 14:22:23 -0400 Date: Fri, 31 Aug 2007 20:22:12 +0200 From: Ingo Molnar To: Venki Pallipadi Cc: Thomas Gleixner , Andrew Morton , linux-kernel Subject: Re: [PATCH] Track accurate idle time with tick_sched.idle_sleeptime Message-ID: <20070831182212.GA3568@elte.hu> References: <20070827215611.GA30396@linux-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070827215611.GA30396@linux-os.sc.intel.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0004] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Venki Pallipadi wrote: > Current idle time in kstat is based on jiffies and is coarse grained. > tick_sched.idle_sleeptime is making some attempt to keep track of idle > time in a fine grained manner. But, it is not handling the time spent > in interrupts fully. > > Make tick_sched.idle_sleeptime accurate with respect to time spent on > handling interrupts and also add tick_sched.idle_lastupdate, which > keeps track of last time when idle_sleeptime was updated. > > This statistics will be crucial for cpufreq-ondemand governor, which > can shed some conservative gaurd band that is uses today while setting > the frequency. The ondemand changes that uses the exact idle time is > coming soon. nice stuff! I've added your patch to the scheduler queue - but this will probably be 2.6.24 material. Acked-by: Ingo Molnar Ingo