Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760465Ab3EXKcx (ORCPT ); Fri, 24 May 2013 06:32:53 -0400 Received: from mail-oa0-f52.google.com ([209.85.219.52]:37238 "EHLO mail-oa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760434Ab3EXKct (ORCPT ); Fri, 24 May 2013 06:32:49 -0400 MIME-Version: 1.0 In-Reply-To: <519F40D8.7040500@linaro.org> References: <1367590072-10496-1-git-send-email-jonghwa3.lee@samsung.com> <20130522122700.104ca5cd@amdc308.digital.local> <20130522164453.29cd3a7d@amdc308.digital.local> <20130524075640.0a5b80ff@amdc308.digital.local> <20130524103007.7bb206ee@amdc308.digital.local> <519F2D89.5030602@linaro.org> <519F40D8.7040500@linaro.org> Date: Fri, 24 May 2013 16:02:48 +0530 Message-ID: Subject: Re: [RFC v2 0/3][TESTS] LAB: Support for Legacy Application Booster governor - tests results From: Viresh Kumar To: Daniel Lezcano Cc: Lukasz Majewski , Jonghwa Lee , "Rafael J. Wysocky" , linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, Vicent Guittot , MyungJoo Ham , Lukasz Majewski Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1675 Lines: 34 On 24 May 2013 15:58, Daniel Lezcano wrote: > On 05/24/2013 11:13 AM, Viresh Kumar wrote: >> Consider how will we achieve it for big LITTLE.. We know we can >> go to overdrive only for a single core in big but for two cores in >> LITTLE at the same time.. So, we need that in the location I just >> mentioned... > > I thought the constraints should be hardcoded in the driver and only one > option is exposed to the userspace. If the user sets > ondemand|performance + boost, then the exynos's or b.L's drivers know > when they can go to boost (1x core, 1x big core, 2x little core, ...). Cpufreq Drivers don't take a decision on cpu frequency. They just provide a mechanism to cpufreq core.. Decision must come from governor all the time. >> I didn't get it completely.. So, with the options I gave user can only >> say.. boost if required and only when few cores are active. User >> can't just set max freq continuously if he wishes.. > > Ok, may be I misunderstood. You suggested to define 'overdrive_cores' > where the user can setup when to overdrive a core. If the user set an > incorrect value, IIUC, the thermal value can go beyond the thermal limit > and break the board. I am just worried this option is dangerous. Yes.. if we set 4 at that place.. 4 cores may run together in overdrive mode. And that is risky :) ... Maybe a max limit from driver will be another option along with this. -- 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/