From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753499Ab0EDESN (ORCPT ); Tue, 4 May 2010 00:18:13 -0400 Received: from 1wt.eu ([62.212.114.60]:63667 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752351Ab0EDESJ (ORCPT ); Tue, 4 May 2010 00:18:09 -0400 Date: Tue, 4 May 2010 06:16:57 +0200 From: Willy Tarreau To: Arjan van de Ven Cc: Thomas Renninger , Pavel Machek , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mingo@elte.hu, peterz@infradead.org, tglx@linutronix.de, davej@redhat.com, cpufreq@vger.kernel.org, riel@redhat.com Subject: Re: [PATCH 8/7] cpufreq: make the iowait-is-busy-time a sysfs tunable Message-ID: <20100504041657.GC13686@1wt.eu> References: <20100418115949.7b743898@infradead.org> <201004231050.10667.trenn@suse.de> <20100423090819.4273b327@infradead.org> <201004271339.34711.trenn@suse.de> <20100503204818.7b801f43@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100503204818.7b801f43@infradead.org> 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 On Mon, May 03, 2010 at 08:48:18PM -0700, Arjan van de Ven wrote: > From: Arjan van de Ven > Subject: [PATCH] cpufreq: make the iowait-is-busy-time a sysfs tunable > > Pavel Machek pointed out that not all CPUs have an efficient idle > at high frequency. Specifically, older Intel and various AMD cpus > would get a higher power usage when copying files from USB. > > Mike Chan pointed out that the same is true for various ARM chips > as well. > > Thomas Renninger suggested to make this a sysfs tunable with a > reasonable default. > > This patch adds a sysfs tunable for the new behavior, and uses > a very simple function to determine a reasonable default, depending > on the CPU vendor/type. > > Signed-off-by: Arjan van de Ven > --- That's very nice Arjan. That way we'll be able to select between performance and power savings, which is what most laptop users want after all ! Thanks, Willy