Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932221AbVLDOdn (ORCPT ); Sun, 4 Dec 2005 09:33:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932235AbVLDOdn (ORCPT ); Sun, 4 Dec 2005 09:33:43 -0500 Received: from isilmar.linta.de ([213.239.214.66]:40640 "EHLO linta.de") by vger.kernel.org with ESMTP id S932221AbVLDOdn (ORCPT ); Sun, 4 Dec 2005 09:33:43 -0500 Date: Sun, 4 Dec 2005 15:33:37 +0100 From: Dominik Brodowski To: Con Kolivas Cc: linux kernel mailing list , ck list , Tony Lindgren , Adam Belay , Daniel Petrini , vatsa@in.ibm.com Subject: Dyntick effectiveness [Was: [PATCH] i386 no idle HZ aka Dynticks 051203] Message-ID: <20051204143337.GA4572@isilmar.linta.de> Mail-Followup-To: Dominik Brodowski , Con Kolivas , linux kernel mailing list , ck list , Tony Lindgren , Adam Belay , Daniel Petrini , vatsa@in.ibm.com References: <200512041737.07996.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200512041737.07996.kernel@kolivas.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1573 Lines: 48 On Sun, Dec 04, 2005 at 05:37:05PM +1100, Con Kolivas wrote: > Here is an updated complete patch implementing no idle hz ticks > aka dynticks for i386. A few stats about running dynticks on my notebook (1.4G Pentium M) CPU frequency C4 dyntick avg. battery rate[*] ------------------------------------------------------------ 0.6 GHz on off 990 mA 0.6 GHz on on 973 mA (-2%) 1.4 GHz on off 1400 mA fan starts very soon (~15sec) 1.4 GHz on on 1100 mA (-21%) fan starts after ~5min 0.6 GHz off off 1130 mA 0.6 GHz off on 1050 mA (-7%) 1.4 GHz off off 1480 mA 1.4 GHz off on 1180 mA (-20%) [*] as reported by cat /proc/acpi/battery/BAT1/state . Power consumption during normal operation (C0) and in processor idle states, as per datasheet: speed C0 C1 C2 C3 C4 ----------------------------------------------------- 1.4GHz 22W 7.3W 7.3W 5.1W 0.55W 0.6GHz 6W 1.8W 1.8W 1.1W 0.55W => Most useful when CPU frequency scaling isn't available (Celerons? Do they have "Deeper Sleep State" -- no, they don't. That's why I did the test run with C4 disabled. The values for 1.4G without C4 should be similar to what can be seen on Celerons.) => Only minimal additional power savings when CPU frequency scaling works well => Possible reason: entering power states takes more time when at higher speed Dominik - 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/