From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262494AbTD3XL6 (ORCPT ); Wed, 30 Apr 2003 19:11:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262523AbTD3XL6 (ORCPT ); Wed, 30 Apr 2003 19:11:58 -0400 Received: from [12.47.58.20] ([12.47.58.20]:4207 "EHLO pao-ex01.pao.digeo.com") by vger.kernel.org with ESMTP id S262494AbTD3XL4 (ORCPT ); Wed, 30 Apr 2003 19:11:56 -0400 Date: Wed, 30 Apr 2003 16:21:08 -0700 From: Andrew Morton To: Rick Lindsley Cc: solt@dns.toxicfilms.tv, linux-kernel@vger.kernel.org, frankeh@us.ibm.com Subject: Re: must-fix list for 2.6.0 Message-Id: <20030430162108.09dbd019.akpm@digeo.com> In-Reply-To: <200304302311.h3UNB2H27134@owlet.beaverton.ibm.com> References: <20030430121105.454daee1.akpm@digeo.com> <200304302311.h3UNB2H27134@owlet.beaverton.ibm.com> X-Mailer: Sylpheed version 0.8.9 (GTK+ 1.2.10; i586-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 30 Apr 2003 23:24:10.0599 (UTC) FILETIME=[9A98AF70:01C30F6F] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rick Lindsley wrote: > > Why is this bad? > (a) if it does busy looping through sched_yield it will eat cycles which > might not have happened Things like OpenOffice _do_ busy loop on sched_yield(). It appears with that patch, OO will sit there chewing ~1% of CPU. Not great, but not bad either.. A few kernels ago, OpenOffice would take sixty seconds to just flop down a menu if there was a kernel build happening at the same time. That is just utterly broken, so if we're going to leave the sched.c code as-is then we *require* that all applications be updated to not spin on sched_yield. There's just no question about that. It may end up not being acceptable. Has anyone looked at what Andrea did in -aa? I assume some suitable compromise was achieved there.