From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 3/6 v4] cpufreq: tolerate inexact values when collecting stats Date: Sat, 24 Nov 2012 11:05:09 +0100 Message-ID: <3756540.1nyvqzWibd@vostro.rjw.lan> References: <1351631056-25938-1-git-send-email-mark.langsdorf@calxeda.com> <21672683C5A3814BB4DB938EBE482DE426EA988080@IAD2MBX09.mex02.mlsrvr.com> <20121117145048.GI16441@x1.osrc.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20121117145048.GI16441@x1.osrc.amd.com> Sender: cpufreq-owner@vger.kernel.org To: Mark Langsdorf Cc: Borislav Petkov , "linux-kernel@vger.kernel.org" , "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , MyungJoo Ham List-Id: linux-pm@vger.kernel.org On Saturday, November 17, 2012 03:50:48 PM Borislav Petkov wrote: > On Tue, Nov 13, 2012 at 02:13:38PM -0500, Mark Langsdorf wrote: > > Although cpufreq_driver has a flag field, no part of cpufreq_driver > > is directly passed to the cpufreq_stat code. Only cpufreq_policy > > is. It's cleaner to do passes of the while loop than to copy the > > cpufreq_driver.flag field into cpufreq_policy and then store it again > > in cpufreq_stats. > > That maybe so but this newly added loop which is only Calxeda-relevant > is called in cpufreq_stat_notifier_trans, which is the frequency change > notifier call, AFAICT. > > So each cpufreq driver will be paying that small and needless penalty > now for nothing and on each frequency change. Which adds to the > kernel-wide bloat and we absolutely don't want that. > > So you probably need to find a slick way of detecting calxeda hw > somewhere along the init path of cpufreq_stats_init and set a > hw-specific flag instead of adding that cost to each driver. Mark, I suppose you'd like me to take this series for v3.8, but the above comment from Boris has to be addressed for that. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.