From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932743AbZHDK2W (ORCPT ); Tue, 4 Aug 2009 06:28:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932693AbZHDK2W (ORCPT ); Tue, 4 Aug 2009 06:28:22 -0400 Received: from lennier.cc.vt.edu ([198.82.162.213]:52883 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932694AbZHDK2V (ORCPT ); Tue, 4 Aug 2009 06:28:21 -0400 From: "Sherif F. Fahmy" To: "'Casey Dahlin'" Cc: References: <1249312084.5762.17.camel@sherif-laptop> <4A774858.6080106@redhat.com> In-Reply-To: <4A774858.6080106@redhat.com> Subject: RE: scheduling co-processors Date: Tue, 4 Aug 2009 13:28:00 +0300 Message-ID: <000301ca14ee$401f8560$c05e9020$@edu> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcoUd9rrVmP+XMexRxqFgj/EwdFB0AAdkVnQ Content-Language: en-us X-Mirapoint-Received-SPF: 198.82.161.152 auth3.smtp.vt.edu fahmy@vt.edu 2 pass X-Mirapoint-IP-Reputation: reputation=neutral-1, source=Fixed, refid=n/a, actions=MAILHURDLE SPF TAG X-Junkmail-Info: (0) X-Junkmail-Status: score=10/50, host=dagger.cc.vt.edu X-Junkmail-SD-Raw: score=unknown, refid=str=0001.0A020201.4A780D35.0050,ss=1,fgs=0, ip=41.196.91.126, so=2009-06-02 18:41:42, dmn=2009-06-06 00:02:10, mode=multiengine X-Junkmail-IWF: false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel- > owner@vger.kernel.org] On Behalf Of Casey Dahlin > Sent: Monday, August 03, 2009 11:28 PM > To: Sherif Fadel > Cc: linux-kernel@vger.kernel.org > Subject: Re: scheduling co-processors > > On 08/03/2009 11:08 AM, Sherif Fadel wrote: > > Hi, > > > > I have a dual-core system on which I would like to treat one > processor > > as a scheduling co-processor. I have already implemented some custom > > scheduling policies and tested them with SMP disabled, I would not > like > > to see if it is possible to have the scheduling algorithm running on > one > > core and the scheduled tasks running on another. > > > > I do not know if I can somehow use cpus_allowed to restrict the > kernel > > to one core and the running tasks to another. Is this possible? If > so, > > could you please inform me how one would go about this? > > > > In case you are wondering why I would need this, I am writing a bunch > of > > high-overhead distributed scheduling algorithms and I want to > mitigate > > their overhead in this way. > > > > Thanks. > > > > The design I would have for this would be to have a kthread that does > whatever busy work your scheduler has as a separate process. You could > then replace the existing scheduler with a sort of "schedulerlet" that > would simply schedule according to directions queued up for it by the > kthread task. From there cpu affinity should get you the "dedicated > scheduler processor" you want. > > I can't even begin to envision the scheduling algorithm that would be > able to operate this way, but I have to assume that if it makes sense > for your scheduler to run on another CPU then it must be able to fit > into this pattern. Thanks for the info. I think that this will do perfectly. > > --CJD > -- > 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/