From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754085AbXDOXjo (ORCPT ); Sun, 15 Apr 2007 19:39:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754088AbXDOXjo (ORCPT ); Sun, 15 Apr 2007 19:39:44 -0400 Received: from holomorphy.com ([66.93.40.71]:58704 "EHLO holomorphy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754085AbXDOXjo (ORCPT ); Sun, 15 Apr 2007 19:39:44 -0400 Date: Sun, 15 Apr 2007 16:39:09 -0700 From: William Lee Irwin III To: Ingo Molnar Cc: Matt Mackall , Con Kolivas , Peter Williams , linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Nick Piggin , Mike Galbraith , Arjan van de Ven , Thomas Gleixner Subject: Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS] Message-ID: <20070415233909.GE2986@holomorphy.com> References: <20070413202100.GA9957@elte.hu> <200704151327.13589.kernel@kolivas.org> <20070415150536.GA6623@elte.hu> <20070415200535.GC11166@waste.org> <20070415204824.GA25813@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070415204824.GA25813@elte.hu> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Apr 15, 2007 at 10:48:24PM +0200, Ingo Molnar wrote: > 2) plugsched did not allow on the fly selection of schedulers, nor did > it allow a per CPU selection of schedulers. IO schedulers you can > change per disk, on the fly, making them much more useful in > practice. Also, IO schedulers (while definitely not being slow!) are > alot less performance sensitive than CPU schedulers. One of the reasons I never posted my own code is that it never met its own design goals, which absolutely included switching on the fly. I think Peter Williams may have done something about that. It was my hope to be able to do insmod sched_foo.ko until it became clear that the effort it was intended to assist wasn't going to get even the limited hardware access required, at which point I largely stopped working on it. On Sun, Apr 15, 2007 at 10:48:24PM +0200, Ingo Molnar wrote: > 3) I/O schedulers are pretty damn clean code, and plugsched, at least > the last version i saw of it, didnt come even close. I'm not sure what happened there. It wasn't a big enough patch to take hits in this area due to getting overwhelmed by the programming burden like some other efforts of mine. Maybe things started getting ugly once on-the-fly switching entered the picture. My guess is that Peter Williams will have to chime in here, since things have diverged enough from my one-time contribution 4 years ago. -- wli