Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753263AbZGXPl3 (ORCPT ); Fri, 24 Jul 2009 11:41:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753223AbZGXPl2 (ORCPT ); Fri, 24 Jul 2009 11:41:28 -0400 Received: from ey-out-2122.google.com ([74.125.78.25]:19361 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753220AbZGXPl1 (ORCPT ); Fri, 24 Jul 2009 11:41:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=e+rcG2XYlGp0DAYx0tTPzCRDW2uUBW61hF1iUyeqUVqhYY+w81F/jt95eAYkq8sGiK qoMNHotjFkhSklRehA6MisRGSl6TiCIKY1cVFIb7cDTvBbsggLYR4i/nokSpJ8fovWcF RU6DyPQbR3RYSraeDqLWPmsEi1/dOa6KNNPGw= MIME-Version: 1.0 In-Reply-To: <20090723150517.fbbd03dc.akpm@linux-foundation.org> References: <200907191659.47179.czoccolo@gmail.com> <20090723150517.fbbd03dc.akpm@linux-foundation.org> Date: Fri, 24 Jul 2009 17:41:26 +0200 Message-ID: <4e5e476b0907240841y183a4c08r3abf3d4fb7489284@mail.gmail.com> Subject: Re: [PATCH] cpuidle: menu governor: reduce latency on exit From: Corrado Zoccolo To: Andrew Morton Cc: venkatesh.pallipadi@intel.com, abelay@novell.com, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1353 Lines: 39 Hi Andrew, the expected effect is to reduce processor wakeup latency from sleep (C-states). We are speaking of few hundreds of cycles reduction out of a several microseconds latency (determined by the hardware transition), so it is difficult to measure. Corrado On Fri, Jul 24, 2009 at 12:05 AM, Andrew Morton wrote: > On Sun, 19 Jul 2009 16:59:46 +0200 > Corrado Zoccolo wrote: > >> This patch moves the state residency accounting and statistics >> computation off the hot exit path. >> On exit, the need to recompute statistics is recorded, and new >> statistics will be computed when menu_select is called again. >> > > Was there any observed and/or measured effect as a result of this patch? > > If so, please send a description of that effect, thanks. > > -- __________________________________________________________________________ dott. Corrado Zoccolo mailto:czoccolo@gmail.com PhD - Department of Computer Science - University of Pisa, Italy -------------------------------------------------------------------------- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/