From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1160999AbXDVX0p (ORCPT ); Sun, 22 Apr 2007 19:26:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161023AbXDVX0p (ORCPT ); Sun, 22 Apr 2007 19:26:45 -0400 Received: from smtp1.linux-foundation.org ([65.172.181.25]:34773 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1160999AbXDVX0o (ORCPT ); Sun, 22 Apr 2007 19:26:44 -0400 Date: Sun, 22 Apr 2007 16:24:47 -0700 (PDT) From: Linus Torvalds To: Juliusz Chroboczek cc: Con Kolivas , Ingo Molnar , ck list , Bill Davidsen , Willy Tarreau , William Lee Irwin III , linux-kernel@vger.kernel.org, Andrew Morton , Nick Piggin , Mike Galbraith , Arjan van de Ven , Peter Williams , Thomas Gleixner , caglar@pardus.org.tr, Gene Heskett Subject: Re: [REPORT] cfs-v4 vs sd-0.44 In-Reply-To: <87647oblx5.fsf@pps.jussieu.fr> Message-ID: References: <20070420140457.GA14017@elte.hu> <200704220155.20856.kernel@kolivas.org> <20070421160008.GA28783@elte.hu> <200704220959.34978.kernel@kolivas.org> <87647oblx5.fsf@pps.jussieu.fr> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 22 Apr 2007, Juliusz Chroboczek wrote: > > Why not do it in the X server itself? This will avoid controversial > policy in the kernel, and have the added advantage of working with > X servers that don't directly access hardware. It's wrong *wherever* you do it. The X server should not be re-niced. It was done in the past, and it was wrogn then (and caused problems - we had to tell people to undo it, because some distros had started doing it by default). If you have a single client, the X server is *not* more important than the client, and indeed, renicing the X server causes bad patterns: just because the client sends a request does not mean that the X server should immediately be given the CPU as being "more important". In other words, the things that make it important that the X server _can_ get CPU time if needed are all totally different from the X server being "more important". The X server is more important only in the presense of multiple clients, not on its own! Needing to renice it is a hack for a bad scheduler, and shows that somebody doesn't understand the problem! Linus