From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: [PATCH] cpufreq: Fix ondemand governor powersave_bias execution time misuse Date: Sun, 07 Nov 2010 20:32:42 -0800 Message-ID: <4CD77D6A.9070901@linux.intel.com> References: <20101105151951.GA10743@linux-youquan.bj.intel.com> <4CD3EF31.9060909@linux.intel.com> <20101108144527.GA13617@linux-youquan.bj.intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20101108144527.GA13617@linux-youquan.bj.intel.com> Sender: cpufreq-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Youquan Song Cc: davej@redhat.com, venki@google.com, youquan.song@intel.com, cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org 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.....