From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: + restore-missing-sysfs-max_cstate-attr.patch added to -mm tree Date: Wed, 02 Jan 2008 18:41:55 -0500 Message-ID: <477C2143.8090406@rtr.ca> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:3404 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757197AbYABXl5 (ORCPT ); Wed, 2 Jan 2008 18:41:57 -0500 In-Reply-To: <4750D585.1030200@rtr.ca> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org 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 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 ? Thanks