From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751744AbWFCRkb (ORCPT ); Sat, 3 Jun 2006 13:40:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751746AbWFCRkb (ORCPT ); Sat, 3 Jun 2006 13:40:31 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:3532 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S1751744AbWFCRkb (ORCPT ); Sat, 3 Jun 2006 13:40:31 -0400 Subject: Re: [patch] cfq: ioprio inherit rt class From: Lee Revell To: Con Kolivas Cc: linux-kernel@vger.kernel.org, Jens Axboe , ck list In-Reply-To: <200606031010.08794.kernel@kolivas.org> References: <200605271150.41924.kernel@kolivas.org> <20060602171215.GM4400@suse.de> <200606031010.08794.kernel@kolivas.org> Content-Type: text/plain Date: Sat, 03 Jun 2006 13:40:28 -0400 Message-Id: <1149356428.28744.27.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2006-06-03 at 10:10 +1000, Con Kolivas wrote: > On Saturday 03 June 2006 03:12, Jens Axboe wrote: > > Not sure. RT io needs to be considered carefully, but I guess so does RT > > CPU scheduling. For now I'd prefer to play it a little safer, and only > > inheric the priority value and not the class. > > The problem I envisioned with that was that realtime tasks, if they don't > specify an io priority (as most current code doesn't), would basically get io > priority 4 and have the same proportion as any nice 0 SCHED_NORMAL task > whereas -nice tasks automatically are getting better io priority. How about > givent them normal class but best priority so they are at least getting the > same as nice -20? > Con, Have you seen RT threads trying to disk IO 'in the wild' or is this a theoretical concern? I don't know of any such apps. Lee