Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758930AbYHKX7c (ORCPT ); Mon, 11 Aug 2008 19:59:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758562AbYHKX6U (ORCPT ); Mon, 11 Aug 2008 19:58:20 -0400 Received: from casper.infradead.org ([85.118.1.10]:34494 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758545AbYHKX6T (ORCPT ); Mon, 11 Aug 2008 19:58:19 -0400 Date: Mon, 11 Aug 2008 16:58:16 -0700 From: Arjan van de Ven To: Dominik Brodowski Cc: Adrian Bunk , S K , Zhao Yakui , Thomas Renninger , Alan Jenkins , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: cpufreq doesn't seem to work in Intel Q9300 Message-ID: <20080811165816.679cfdb9@infradead.org> In-Reply-To: <20080811193316.GA16631@isilmar.linta.de> References: <514e099a0808030300u140a0ae7m92a2e7294f39f7b7@mail.gmail.com> <200808081430.43012.trenn@suse.de> <200808092059.47863.trenn@suse.de> <514e099a0808100128u303207clcb22292db2f0cc59@mail.gmail.com> <1218418431.6671.52.camel@yakui_zhao.sh.intel.com> <514e099a0808102144n241c8e9ak255bded0a80744f1@mail.gmail.com> <20080811042244.469f8e1d@infradead.org> <20080811140206.GB3338@cs181140183.pp.htv.fi> <20080811071128.0165be50@infradead.org> <20080811193316.GA16631@isilmar.linta.de> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1526 Lines: 41 On Mon, 11 Aug 2008 21:33:17 +0200 Dominik Brodowski wrote: > Hi, > > On Mon, Aug 11, 2008 at 07:11:28AM -0700, Arjan van de Ven wrote: > > 1) when the cpu is idle (as in "idle loop C states/hlt"; p4_clockmod > > doesn't mean anything.. the clock is stopped not just skipped. > > 2) when the cpu is executing code (eg non-idle), it takes more power > > for a unit of time than it takes when it's idle > > This statement might be true, but might also be wrong: > a) on systems where only C1 is exported, p4-clockmod most > often equals the state the CPU is in when in C1[*], that's.. not entirely true btw. >so we're in a > win-win, or lose-lose situation. even if it were EXACTLY identical (which it isn't).. you would be at BEST a tie... not a savings. so it's lose-lose or tie-tie, but never win > b) IIRC 50% throttling is not "execute-one-statement > skip-one-statement execute-one-statement, etc." but instead > work for N us, skip for N us, work for N us, etc. > Therefore, the situation is a bit more compilcated. doesn't change the fundamental math though. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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/