From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262858AbVHEFQ3 (ORCPT ); Fri, 5 Aug 2005 01:16:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262859AbVHEFQ3 (ORCPT ); Fri, 5 Aug 2005 01:16:29 -0400 Received: from mail18.syd.optusnet.com.au ([211.29.132.199]:58835 "EHLO mail18.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S262858AbVHEFQ2 (ORCPT ); Fri, 5 Aug 2005 01:16:28 -0400 From: Con Kolivas To: Vojtech Pavlik Subject: Re: [PATCH] i386 No-Idle-Hz aka Dynamic-Ticks 3 Date: Fri, 5 Aug 2005 15:12:18 +1000 User-Agent: KMail/1.8.1 Cc: Jan De Luyck , linux-kernel@vger.kernel.org, ck@vds.kolivas.org, tony@atomide.com, tuukka.tikkanen@elektrobit.com References: <200508031559.24704.kernel@kolivas.org> <200508031624.00319.lkml@kcore.org> <20050804150341.GA10282@ucw.cz> In-Reply-To: <20050804150341.GA10282@ucw.cz> MIME-Version: 1.0 Content-Type: Multipart/Mixed; boundary="Boundary-00=_yUv8CUP3JOPYPXo" Message-Id: <200508051512.18500.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --Boundary-00=_yUv8CUP3JOPYPXo Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Fri, 5 Aug 2005 01:03 am, Vojtech Pavlik wrote: > On Wed, Aug 03, 2005 at 04:23:59PM +0200, Jan De Luyck wrote: > > On Wednesday 03 August 2005 14:14, Con Kolivas wrote: > > > On Wed, 3 Aug 2005 21:54, Jan De Luyck wrote: > > > > On Wednesday 03 August 2005 07:59, Con Kolivas wrote: > > > > > This is the dynamic ticks patch for i386 as written by Tony Lindgen > > > > > and Tuukka Tikkanen > > > > > . Patch for 2.6.13-rc5 > > > > > > > > Compiles and runs ok here. > > > > > > > > Is there actually any timer frequency that's advisable to set as > > > > maximum? (in the kernel config) > > > > > > I'd recommend 1000. > > > > Thanks. Currently the system - under X, KDE, no artsd, bottoms at around > > 300HZ. In total single mode with every module unloaded that I can unload > > it stops around 22HZ. > > > > I guess I'll have to go hunting whatever thing is causing the pollings. > > no timertop yet, I guess? :P > > i8042 runs a steady periodic 20Hz timer. You can make it slower to get > even the total low lower, and it will not affect performance under > normal (sane hardware) circumstances. Indeed and this patch (safely tried at home but serves no useful purpose really) confirms a reasonable drop without problems. After this, only fbcon polls at a similar rate (HZ/5). Of interest to those using an ondemand scaling governor, now that we have timertop, I have found that the default ondemand settings lead to delayed_work_timer_fn at about 140Hz and this can be dropped substantially by slowing the rate of polling (and subsequently slowing the speed with which the ondemand governor responds) down to <25 by echo 100000 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/sampling_rate (the default is 10000 and the value is confusing as the rate goes down as you increase this value). Cheers, Con --Boundary-00=_yUv8CUP3JOPYPXo Content-Type: text/x-diff; charset="iso-8859-1"; name="i8042_slowpoll.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="i8042_slowpoll.patch" Index: linux-2.6.13-rc5-ck2/drivers/input/serio/i8042.h =================================================================== --- linux-2.6.13-rc5-ck2.orig/drivers/input/serio/i8042.h 2005-07-06 16:56:52.000000000 +1000 +++ linux-2.6.13-rc5-ck2/drivers/input/serio/i8042.h 2005-08-05 15:03:49.000000000 +1000 @@ -44,7 +44,7 @@ * polling. */ -#define I8042_POLL_PERIOD HZ/20 +#define I8042_POLL_PERIOD HZ/5 /* * Status register bits. --Boundary-00=_yUv8CUP3JOPYPXo--