From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760334Ab2CTOtI (ORCPT ); Tue, 20 Mar 2012 10:49:08 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:57980 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760127Ab2CTOtE convert rfc822-to-8bit (ORCPT ); Tue, 20 Mar 2012 10:49:04 -0400 MIME-Version: 1.0 In-Reply-To: <37CAE120BAE10B42A790DD1418C8021D0136C7@DNCE02.ent.ti.com> References: <1316475315-5905-1-git-send-email-khilman@ti.com> <87d3d75zo6.fsf@ti.com> <4EBA6046.2060305@linux.vnet.ibm.com> <37CAE120BAE10B42A790DD1418C8021D0136C7@DNCE02.ent.ti.com> Date: Tue, 20 Mar 2012 20:19:02 +0530 Message-ID: Subject: Re: [PATCH] CPUIdle: Reevaluate C-states under CPU load to favor deeper C-states From: melwyn lobo To: "Chalhoub, Nicole" , "Hilman, Kevin" Cc: Deepthi Dharwar , "linux-kernel@vger.kernel.org" , Arjan van de Ven , "linux-arm-kernel@lists.infradead.org" , "linux-omap@vger.kernel.org" , "linux-pm@lists.linux-foundation.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey Kevin, I would like to try out this patch in my platform see the benefits that you are reporting. But there is one issue in this patch. You have not initialized "hrtimer_timeout" variable. This will always be 0 right ?. Thanks, -M On Wed, Nov 9, 2011 at 11:36 PM, Chalhoub, Nicole wrote: > Hi Deepthi, > >> > Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920 > > -----Original Message----- >> From: Deepthi Dharwar [mailto:deepthi@linux.vnet.ibm.com] >> Sent: Wednesday, November 09, 2011 12:13 PM >> To: Hilman, Kevin >> Cc: linux-kernel@vger.kernel.org; Arjan van de Ven; linux-arm- >> kernel@lists.infradead.org; linux-omap@vger.kernel.org; linux- >> pm@lists.linux-foundation.org; Chalhoub, Nicole >> Subject: Re: [PATCH] CPUIdle: Reevaluate C-states under CPU load to favor >> deeper C-states > > [...] >> By setting timers when we enter non-deepest C-state possible, such that >> when it fires we >> can re-evaluate and try moving into deeper and deeper C-states enhancing >> the >> power savings is a good feature to have. >> >> Looking at the current implementation, is it possible to have it as >> configurable option >> where one can enable/disable this functionality through the backhand >> driver ? > > The timeout values of the c state timers are set in the backhand driver. > By setting the timeout to 0 the timers will not fire so you'll not have this functionality enabled > >> Also I am thinking, instead of having them in governor >> wouldnt it be a good idea to have it implemented in >> the backhand driver itself ? >> --Deepthi > > > In fact each C-state had its own configurable timer, so it is a parameter characterizing a C-state as it is for the exit_latency and target_residency parameters. > And we wanted the timer to fire only when we do not go in deep Cstate due to a high load. This decision is made in the CPU idle governor. So the functionality should be seen from the governor.. > > Thanks and Regards > Nicole > > > -- > 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/