From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755563AbYACAGU (ORCPT ); Wed, 2 Jan 2008 19:06:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752707AbYACAGH (ORCPT ); Wed, 2 Jan 2008 19:06:07 -0500 Received: from mga02.intel.com ([134.134.136.20]:46849 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752514AbYACAGG convert rfc822-to-8bit (ORCPT ); Wed, 2 Jan 2008 19:06:06 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.24,237,1196668800"; d="scan'208";a="248244750" X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree Date: Wed, 2 Jan 2008 16:06:20 -0800 Message-ID: <924EFEDD5F540B4284297C4DC59F3DEE4FC485@orsmsx423.amr.corp.intel.com> In-Reply-To: <477C2143.8090406@rtr.ca> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree Thread-Index: AchNmSPBJBO5xTHyQ/u4ZGEjBV027wAAHVNA References: <200711302153.lAULrZ7n026255@imap1.linux-foundation.org> <924EFEDD5F540B4284297C4DC59F3DEE2FAE6A@orsmsx423.amr.corp.intel.com> <20071130142058.816d1693.akpm@linux-foundation.org> <924EFEDD5F540B4284297C4DC59F3DEE2FAEAF@orsmsx423.amr.corp.intel.com> <4750CC78.9070105@rtr.ca> <20071130190227.1976e682@laptopd505.fenrus.org> <4750D180.6080001@rtr.ca> <20071130191816.3e744205@laptopd505.fenrus.org> <4750D585.1030200@rtr.ca> <477C2143.8090406@rtr.ca> From: "Pallipadi, Venkatesh" To: "Mark Lord" , "Arjan van de Ven" Cc: "Andrew Morton" , , , "Ingo Molnar" , , X-OriginalArrivalTime: 03 Jan 2008 00:05:38.0106 (UTC) FILETIME=[5ED121A0:01C84D9C] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >-----Original Message----- >From: Mark Lord [mailto:lkml@rtr.ca] >Sent: Wednesday, January 02, 2008 3:42 PM >To: Arjan van de Ven >Cc: Pallipadi, Venkatesh; Andrew Morton; abelay@novell.com; >lenb@kernel.org; Ingo Molnar; linux-kernel@vger.kernel.org; >linux-acpi@vger.kernel.org >Subject: Re: + restore-missing-sysfs-max_cstate-attr.patch >added to -mm tree > >Arjan van de Ven wrote: >> On Fri, 30 Nov 2007 22:31:17 -0500 >> Mark Lord wrote: >> >>> Arjan van de Ven wrote: >>>> On Fri, 30 Nov 2007 22:14:08 -0500 >>>> Mark Lord wrote: >>>> >>>>>> in -mm there is.. the QoS stuff allows you to set maximum >>>>>> tolerable >>>>> .. >>>>> >>>>> That's encouraging, I think, but not for 2.6.24. >>>>> >>>>>> latency. If your app cant take any latency, you should set >>>>>> those... and the side effect is that the kernel will not do >>>>>> long-latency C-states or P-state transitions.. >>>>> .. >>>>> >>>>> I don't mind the cpufreq changing (actually, I want it to drop in >>>>> cpugfreq to save power and keep the fan off), but the >C-states just >>>>> kill this app. >>>>> >>>>> The app is VMware. I force the max_state=1 when launching, >>>> ah but then its' even easier... and can be done in 2.6.24 already. >>>> VMWare after all has a kernel module, and the latency stuff is in >>>> 2.6.23 and 2.6.24 available inside the kernel already. >>> .. >>> >>> Oh, I'm perfectly happy to write my own kernel module if that's what >> >> all you need to do in your kernel module is call >> >> add_latency_constraint("mark_wants_his_mouse", 5); >> >> or so >.. > >Dredging up an old regression again now: > >The "make my own module to replace /sys/.../max_cstate" doesn't work >for the single-core machine we use a lot around here. > >VMware is totally sluggish unless I go to another text window >and do this: > > while ( true ); do echo -n ; done > >At which point VMware performs well again, >the same as with "echo 1 > max_cstate" in 2.6.23. > >Anyone got any suggestions on how to fix this regression >or work around it for 2.6.24 ? > Easiest and clean way to do it is to have a driver with set_acceptable_latency() for 1uS or so in init and remove_acceptable_latency() at exit. Thanks, Venki