From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752494Ab0IFMAL (ORCPT ); Mon, 6 Sep 2010 08:00:11 -0400 Received: from cantor2.suse.de ([195.135.220.15]:49405 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751219Ab0IFMAJ (ORCPT ); Mon, 6 Sep 2010 08:00:09 -0400 From: Thomas Renninger Organization: SUSE Products GmbH To: Jean Pihet Subject: Re: [PATCH] tracing, perf: add more power related events Date: Mon, 6 Sep 2010 14:00:05 +0200 User-Agent: KMail/1.13.3 (Linux/2.6.31.5-0.1-desktop; KDE/4.4.3; x86_64; ; ) Cc: discuss@lesswatts.org, linux-pm@lists.linux-foundation.org, Ingo Molnar , Arjan van de Ven , Peter Zijlstra , Len Brown , arjan@infradead.org, Kevin Hilman , linux-kernel@vger.kernel.org References: <201009061243.00479.trenn@suse.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201009061400.05637.trenn@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 06 September 2010 13:27:13 Jean Pihet wrote: > On Mon, Sep 6, 2010 at 12:42 PM, Thomas Renninger wrote: ... > In order to reach an efficient low power mode you > need to ensure that all clocks in a clock domain are idled or cut off > (automatically by the HW or with the intervention of SW drivers). > > The HW complexity requires the tracing of all those clocks/power > states, that is why new events are proposed. Hm, but if the HW can switch clocks behind your back, how do you realize that to throw a perf clock power event then? Theoretically you need to poll to keep track of HW switching the clocks? Thomas