From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938645AbXG1A7o (ORCPT ); Fri, 27 Jul 2007 20:59:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S938353AbXG1A7h (ORCPT ); Fri, 27 Jul 2007 20:59:37 -0400 Received: from mx2.suse.de ([195.135.220.15]:49776 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938352AbXG1A7h (ORCPT ); Fri, 27 Jul 2007 20:59:37 -0400 Date: Sat, 28 Jul 2007 02:59:20 +0200 From: Andrea Arcangeli To: Chris Snook Cc: tim.c.chen@linux.intel.com, mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: Volanomark slows by 80% under CFS Message-ID: <20070728005920.GA31622@v2.random> References: <1185573687.19777.44.camel@localhost.localdomain> <46AA8E57.8010105@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46AA8E57.8010105@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 27, 2007 at 08:31:19PM -0400, Chris Snook wrote: > I think Volanomark is being pretty stupid, and deserves to run slowly, but Indeed, any app doing what volanomark does is pretty inefficient. But this is not the point. I/O schedulers are pluggable to help for inefficient apps too. If apps would be extremely smart they would all use async-io for their reads, and there wouldn't be the need of anticipatory scheduler just for an example. The fact is there's no technical explanation for which we're forbidden to be able to choose between CFS and O(1) at least at boot time.