From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752755AbYJYLJT (ORCPT ); Sat, 25 Oct 2008 07:09:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751508AbYJYLI7 (ORCPT ); Sat, 25 Oct 2008 07:08:59 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:50180 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751197AbYJYLI7 (ORCPT ); Sat, 25 Oct 2008 07:08:59 -0400 From: "Rafael J. Wysocki" To: David Miller Subject: Re: [tbench regression fixes]: digging out smelly deadmen. Date: Sat, 25 Oct 2008 13:13:20 +0200 User-Agent: KMail/1.9.9 Cc: mingo@elte.hu, s0mbre@tservice.net.ru, a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, efault@gmx.de References: <20081010115518.GA3159@tservice.net.ru> <200810250025.35734.rjw@sisk.pl> <20081024.163111.244324800.davem@davemloft.net> In-Reply-To: <20081024.163111.244324800.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200810251313.21120.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday, 25 of October 2008, David Miller wrote: > From: "Rafael J. Wysocki" > Date: Sat, 25 Oct 2008 00:25:34 +0200 > > > On Friday, 10 of October 2008, Ingo Molnar wrote: > > > > > > * Evgeniy Polyakov wrote: > > > > > > > On Fri, Oct 10, 2008 at 01:42:45PM +0200, Ingo Molnar (mingo@elte.hu) wrote: > > > > > > vanilla 27: 347.222 > > > > > > no TSO/GSO: 357.331 > > > > > > no hrticks: 382.983 > > > > > > no balance: 389.802 > > > > > > > > > > okay. The target is 470 MB/sec, right? (Assuming the workload is sane > > > > > and 'fixing' it does not mean we have to schedule worse.) > > > > > > > > Well, that's where I started/stopped, so maybe we will even move > > > > further? :) > > > > > > that's the right attitude ;) > > > > Can anyone please tell me if there was any conclusion of this thread? > > I made some more analysis in private with Ingo and Peter Z. and found > that the tbench decreases correlate pretty much directly with the > ongoing increasing cpu cost of wake_up() and friends in the fair > scheduler. > > The largest increase in computational cost of wakeups came in 2.6.27 > when the hrtimer bits got added, it more than tripled the cost of a wakeup. > In 2.6.28-rc1 the hrtimer feature has been disabled, but I think that > should be backports into the 2.6.27-stable branch. Thanks a lot for the info. Could you please give me a pointer to the commit disabling the hrtimer feature? Rafael