Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754151Ab0KHEcp (ORCPT ); Sun, 7 Nov 2010 23:32:45 -0500 Received: from mga09.intel.com ([134.134.136.24]:16539 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754114Ab0KHEco (ORCPT ); Sun, 7 Nov 2010 23:32:44 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.58,312,1286175600"; d="scan'208";a="675225605" Message-ID: <4CD77D6A.9070901@linux.intel.com> Date: Sun, 07 Nov 2010 20:32:42 -0800 From: Arjan van de Ven User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: Youquan Song CC: davej@redhat.com, venki@google.com, youquan.song@intel.com, cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] cpufreq: Fix ondemand governor powersave_bias execution time misuse References: <20101105151951.GA10743@linux-youquan.bj.intel.com> <4CD3EF31.9060909@linux.intel.com> <20101108144527.GA13617@linux-youquan.bj.intel.com> In-Reply-To: <20101108144527.GA13617@linux-youquan.bj.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1496 Lines: 32 On 11/8/2010 6:45 AM, Youquan Song wrote: >> On 11/5/2010 11:19 AM, Youquan Song wrote: >>> Ondemand governor use powersave_bias tunable to do aggressive power save by >>> decrease CPU average frequency. The average frequency achieve by adjust low and >>> high frequency's execution time proportion during one sample time interval. >>> >>> Current kernel, only the high frequency executes in time proportion, but the low >>> frequency wrongly execute in one whole sample time interval when powersave_bias >>> is set. >>> >>> The patch fix it by set low frequency execution time to it deserved. >>> >>> Signed-off-by: Youquan Song >>> --- >> >> while your patch looks correct, I think the whole feature is wonky and >> likely ought to be removed........... > powersave_bias should be a useful feature, which give user an > opportunity to set the CPU to work at wider average frequency accord to real > workload requirement, not just CPU frequency specific at P0,P1,...Pn. > At the same time, it meets end user power comsumpation requirement in > some degree. > Unfortunately, it does not work for a long time. in all measurements I've done... the intermediate states (between P1 and Pn) seem to not be power efficient..... -- 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/