From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753567AbXCPQnQ (ORCPT ); Fri, 16 Mar 2007 12:43:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965585AbXCPQnQ (ORCPT ); Fri, 16 Mar 2007 12:43:16 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:3729 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753574AbXCPQnP (ORCPT ); Fri, 16 Mar 2007 12:43:15 -0400 Date: Fri, 16 Mar 2007 16:42:45 +0000 From: Pavel Machek To: Con Kolivas Cc: Mike Galbraith , Ingo Molnar , linux kernel mailing list , ck list , Linus Torvalds , Andrew Morton Subject: Re: [PATCH][RSDL-mm 0/7] RSDL cpu scheduler for 2.6.21-rc3-mm2 Message-ID: <20070316164245.GC3951@ucw.cz> References: <200703111457.17624.kernel@kolivas.org> <200703130549.47058.kernel@kolivas.org> <1173730314.6431.30.camel@Homer.simpson.net> <200703130738.19034.kernel@kolivas.org> <1173732344.6431.54.camel@Homer.simpson.net> <8cd998d50703121551u44ea3d85g2541503373f461f4@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8cd998d50703121551u44ea3d85g2541503373f461f4@mail.gmail.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >> > Killing the known corner case starvation scenarios > >is wonderful, but > >> > let's not just pretend that interactive tasks don't > >have any special > >> > requirements. > >> > >> Now you're really making a stretch of things. Where > >on earth did I say that > >> interactive tasks don't have special requirements? > >It's a fundamental feature > >> of this scheduler that I go to great pains to get > >them as low latency as > >> possible and their fair share of cpu despite having a > >completely fair cpu > >> distribution. > > > >As soon as your cpu is fully utilized, fairness looses > >or interactivity > >loses. Pick one. > > That's not true unless you refuse to prioritise your > tasks > accordingly. Let's take this discussion in a different > direction. You > already nice your lame processes. Why? You already have > the concept > that you are prioritising things to normal or background > tasks. You > say so yourself that lame is a background task. Stating > the bleedingly > obvious, the unix way of prioritising things is via > nice. You already > do that. So moving on from that... > > Your test case you ask "how can I maximise cpu usage". > Well you know > the answer already. You run two threads. I won't dispute > that. > > The debate seems to be centered on whether two tasks > that are niced +5 > or to a higher value is background. In my opinion, nice > 5 is not > background, but relatively less cpu. You already are > savvy enough to > be using two threads and nicing them. All I ask you to > do when using > RSDL is to change your expectations slightly and your > settings from > nice 5 to nice 10 or 15 or even 19. Why is that so > offensive to you? > nice 5 is 75% the cpu of nice 0. nice 10 is 50%, nice 15 > is 25%, nice Hmm, I'd certainly expect nice to be stronger. nice 5 should be 50% or less of nice 0... You'll not even notice nice 2 if that is 90%... And I guess it nicely solves problem in this thread, too... -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html