Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755843AbZJBOpw (ORCPT ); Fri, 2 Oct 2009 10:45:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754076AbZJBOpw (ORCPT ); Fri, 2 Oct 2009 10:45:52 -0400 Received: from mail.gmx.net ([213.165.64.20]:60151 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754070AbZJBOpv (ORCPT ); Fri, 2 Oct 2009 10:45:51 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1/5FI4C6fH51MYhNMkkWetq+QkPf/Uwm5TgOBVudH INomGT9/d0Tot5 Subject: Re: IO scheduler based IO controller V10 From: Mike Galbraith To: Linus Torvalds Cc: Jens Axboe , Ingo Molnar , Vivek Goyal , Ulrich Lukas , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, dm-devel@redhat.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, riel@redhat.com In-Reply-To: References: <1254034500.7933.6.camel@marge.simson.net> <20090927164235.GA23126@kernel.dk> <1254340730.7695.32.camel@marge.simson.net> <1254341139.7695.36.camel@marge.simson.net> <20090930202447.GA28236@redhat.com> <1254382405.7595.9.camel@marge.simson.net> <20091001185816.GU14918@kernel.dk> <1254464628.7158.101.camel@marge.simson.net> <20091002080417.GG14918@kernel.dk> <20091002092409.GA19529@elte.hu> <20091002092839.GA26962@kernel.dk> Content-Type: text/plain Date: Fri, 02 Oct 2009 16:45:42 +0200 Message-Id: <1254494742.7307.37.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.63 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 963 Lines: 27 On Fri, 2009-10-02 at 07:24 -0700, Linus Torvalds wrote: > > On Fri, 2 Oct 2009, Jens Axboe wrote: > > > > It's really not that simple, if we go and do easy latency bits, then > > throughput drops 30% or more. > > Well, if we're talking 500-950% improvement vs 30% deprovement, I think > it's pretty clear, though. Even the server people do care about latencies. > > Often they care quite a bit, in fact. > > And Mike's patch didn't look big or complicated. But it is a hack. (thought about and measured, but hack nonetheless) I haven't tested it on much other than reader vs streaming writer. It may well destroy the rest of the IO universe. I don't have the hw to even test any hairy chested IO. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/