From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967262AbXG3Qgn (ORCPT ); Mon, 30 Jul 2007 12:36:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S967153AbXG3Qfr (ORCPT ); Mon, 30 Jul 2007 12:35:47 -0400 Received: from cb2.northrockquote.com ([64.251.14.146]:2939 "EHLO dejavu.debianpt.org" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S967145AbXG3Qfp (ORCPT ); Mon, 30 Jul 2007 12:35:45 -0400 X-Greylist: delayed 1862 seconds by postgrey-1.27 at vger.kernel.org; Mon, 30 Jul 2007 12:35:45 EDT From: Miguel Figueiredo Organization: DebianPT.org To: ck@vds.kolivas.org Subject: Re: [ck] Re: SD still better than CFS for 3d ?(was Re: 2.6.23-rc1) Date: Mon, 30 Jul 2007 17:04:29 +0100 User-Agent: KMail/1.9.5 Cc: Ingo Molnar , Linux Kernel Mailing List References: <930f95dc0707291431j4e50214di3c01cd44b5597502@mail.gmail.com> <20070730114649.GB19186@elte.hu> In-Reply-To: <20070730114649.GB19186@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707301704.29670.elmig@debianpt.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Em Segunda, 30 de Julho de 2007 12:46, Ingo Molnar escreveu: > * John wrote: > > On 7/29/07, Ingo Molnar wrote: > > > * John wrote: > > > > Ingo- > > > > > > > > Why not perform the same test using the native linux Q3 client to > > > > compare numbers to wine? [...] [...] > and that matches my experience as well (as limited as it may be). In > general my impression is that CFS and SD are roughly on par when it > comes to 3D smoothness. > > The Wine+Quake3 numbers i posted yesterday are so bad under SD that they > must be some artifact in SD (possibly related to yield - i've strace-ed > the tasks under SD today and they are blocking in yield), so they are > not really representative of the general quality of SD (unless you are > being hit by that particular regression). Still it is kind of ironic > that when i tried to find a 3D regression in CFS i found a 3D regression > in SD. I also tryied Q3A demo and i got similar values to yours: CFS 90 2.6.22 90 SD 90 while running that endless loop, on 2.6.22 and SD it drops instantly to 4 fps. While CFS runs ~70 with 1.9 load. I was able to play the game without noticing much degradation. I written these values while playing under CFS: load fps 1.66 81 1.73 75 1.97 70s With this patch [1] someone sent me over IRC i get similar values to CFS, maybe a few fps more, but thats insignificant and not very accurate to measure. Anyway with this patch i am playing with a load of 2.2 at ~75 fps, 1024x768 windowed. It's enjoyable to frag the dumb 'Major' as under CFS. I think the main difference in performance of CFS and SD it's the implementation of sched_yield (which is used by graphic drivers) and CFS has changed the implementation of sched_yield. You use: in mainline (2.6.22): /** * sys_sched_yield - yield the current processor to other threads. * * This function yields the current CPU by moving the calling thread * to the expired array. If there are no other threads running on this * CPU then this function will return. */ you changed it to something like: if (unlikely(rq->nr_running == 1)) schedstat_inc(rq, yld_act_empty); else current->sched_class->yield_task(rq, current); wile mainline (2.6.22) and SD use: dequeue_task(current, array); enqueue_task(current, target); and requeue_task() Anyway i am going to continue to frag a bit more :) [1] - http://rafb.net/p/Rbpqaz26.html There are 2 modes for this hack: sysctl kernel.sched_yield = 1 or 2, see patch. [...] > > Ingo > _______________________________________________ > http://ck.kolivas.org/faqs/replying-to-mailing-list.txt > ck mailing list - mailto: ck@vds.kolivas.org > http://vds.kolivas.org/mailman/listinfo/ck -- Com os melhores cumprimentos/Best regards, Miguel Figueiredo http://www.DebianPT.org