From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265258AbTLZXWn (ORCPT ); Fri, 26 Dec 2003 18:22:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265259AbTLZXWn (ORCPT ); Fri, 26 Dec 2003 18:22:43 -0500 Received: from gprs214-253.eurotel.cz ([160.218.214.253]:47232 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S265258AbTLZXWk (ORCPT ); Fri, 26 Dec 2003 18:22:40 -0500 Date: Sat, 27 Dec 2003 00:03:00 +0100 From: Pavel Machek To: Con Kolivas Cc: Nick Piggin , "Nakajima, Jun" , linux kernel mailing list Subject: Re: [PATCH] 2.6.0 batch scheduling, HT aware Message-ID: <20031226230300.GF197@elf.ucw.cz> References: <200312231138.21734.kernel@kolivas.org> <3FE7AF24.40600@cyberone.com.au> <200312231415.38611.kernel@kolivas.org> <200312231416.58998.kernel@kolivas.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200312231416.58998.kernel@kolivas.org> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > >>>I discussed this with Ingo and that's the sort of thing we thought of. > > > >>>Perhaps a relative crossover of 10 dynamic priorities and an absolute > > > >>>crossover of 5 static priorities before things got queued together. > > > >>> This is really only required for the UP HT case. > > > >> > > > >>Well I guess it would still be nice for "SMP HT" as well. Hopefully the > > > >>code can be generic enough that it would just carry over nicely. > > > > > > > >I disagree. I can't think of a real world scenario where 2+ physical > > > > cpus would benefit from this. > > > > > > Well its the same problem. A nice -20 process can still lose 40-55% of > > > its performance to a nice 19 process, a figure of 10% is probably too > > > high and we'd really want it <= 5% like what happens with a single > > > logical processor. > > > > I changed my mind just after I sent that mail. 4 physical cores running > > three nice 20 and one nice -20 task gives the nice -20 task only 25% of the > > total cpu and 25% to each of the nice 20 tasks. > > Err that should read 4 logical cores. Actually, for 4 physical cores it is going to be true, too. And if you are memory-bound, stopping those 3 task can speed your important task, too. Its really same. Pavel -- When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]