From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756269Ab0CXOCe (ORCPT ); Wed, 24 Mar 2010 10:02:34 -0400 Received: from s15228384.onlinehome-server.info ([87.106.30.177]:58926 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752608Ab0CXOCc (ORCPT ); Wed, 24 Mar 2010 10:02:32 -0400 Date: Wed, 24 Mar 2010 15:02:57 +0100 From: Borislav Petkov To: Thomas Renninger Cc: akpm@linux-foundation.org, davej@redhat.com, cpufreq@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, lenb@kernel.org Subject: Re: [PATCH 5/5] cpufreq: Add support for actual freq Message-ID: <20100324140257.GA29754@aftab> References: <1269283121-11894-1-git-send-email-bp@amd64.org> <201003231251.18181.trenn@suse.de> <20100323142349.GG16493@aftab> <201003231612.18907.trenn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201003231612.18907.trenn@suse.de> Organization: Advanced Micro Devices =?iso-8859-1?Q?GmbH?= =?iso-8859-1?Q?=2C_Karl-Hammerschmidt-Str=2E_34=2C_85609_Dornach_bei_M=FC?= =?iso-8859-1?Q?nchen=2C_Gesch=E4ftsf=FChrer=3A_Thomas_M=2E_McCoy=2C_Giuli?= =?iso-8859-1?Q?ano_Meroni=2C_Andrew_Bowd=2C_Sitz=3A_Dornach=2C_Gemeinde_A?= =?iso-8859-1?Q?schheim=2C_Landkreis_M=FCnchen=2C_Registergericht_M=FCnche?= =?iso-8859-1?Q?n=2C?= HRB Nr. 43632 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Renninger Date: Tue, Mar 23, 2010 at 04:12:18PM +0100 Hi Thomas, > would return the average freq of the last seconds, exactly the same > what you can do with cpufreq-aperf from userspace. > But if another user app does the same, it's messed up. > You can find out the pid of the process doing the cat and remember > aperf/mperf for it if it does not exist yet..., but now it gets to a > point where cpufreq-aperf is really more convenient and straight foward. > > Possibly documenting cpufreq-aperf in Documentation/cpu-freq would > be worth it. Also mentioning "boost" somewhere would be great: > grep -i boost Documentation/cpu-freq/ -r > Documentation/cpu-freq/pcc-cpufreq.txt:This is due to "turbo boost" ... > > Another idea is to have a separate cpufreq_avg_freq and update it on > every target() call, but that's overhead... you got me persuaded - if we want to have the effective frequency reported in the kernel, we have to come up with a slick solution that wouldn't incur overhead and won't be disrupted by others accessing those MSRs. Let's leave it to cpufreq-aperf for now and revisit this when needed. Thanks. -- Regards/Gruss, Boris. -- Advanced Micro Devices, Inc. Operating Systems Research Center