From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755650AbZKHWhl (ORCPT ); Sun, 8 Nov 2009 17:37:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755613AbZKHWhl (ORCPT ); Sun, 8 Nov 2009 17:37:41 -0500 Received: from casper.infradead.org ([85.118.1.10]:40840 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755501AbZKHWhk (ORCPT ); Sun, 8 Nov 2009 17:37:40 -0500 Date: Sun, 8 Nov 2009 14:39:08 -0800 From: Arjan van de Ven To: Corrado Zoccolo Cc: linux-kernel@vger.kernel.org, Andrew Morton , lenb@kernel.org, mingo@elte.hu, yanmin_zhang@linux.intel.com, jens.axboe@oracle.com, Ivan Kokshaysky Subject: Re: [PATCH v2] cpuidle: Fix the menu governor to boost IO performance Message-ID: <20091108143908.78dd97a1@infradead.org> In-Reply-To: <4e5e476b0911081359x32d7a6c4x61ee3af92dc0c8a1@mail.gmail.com> References: <20090915054259.5282e5ba@infradead.org> <4e5e476b0911040139h1f471627la4262a5fa66abab0@mail.gmail.com> <20091108124035.23d53197@infradead.org> <4e5e476b0911081359x32d7a6c4x61ee3af92dc0c8a1@mail.gmail.com> Organization: Intel X-Mailer: Claws Mail 3.7.2 (GTK+ 2.16.6; i586-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 8 Nov 2009 22:59:43 +0100 Corrado Zoccolo wrote: > Unfortunately, I have seen polling residency times > 1ms, so it must > not be so accurate. hmm I wonder if the timer hardware in use has a much larger granularity than usecs... because that rounding up could cost us dearly. wonder if we should do some form of "check for timer expiry" as part of the polling loop.. that'd cut latency way down as well ;) -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org