From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752972AbZKDBUN (ORCPT ); Tue, 3 Nov 2009 20:20:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751712AbZKDBUM (ORCPT ); Tue, 3 Nov 2009 20:20:12 -0500 Received: from mga02.intel.com ([134.134.136.20]:44514 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751920AbZKDBUL (ORCPT ); Tue, 3 Nov 2009 20:20:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.44,677,1249282800"; d="scan'208";a="464109871" Subject: Re: kernel building regression on 32-rc5 kernel From: Alex Shi Reply-To: alex.shi@intel.com To: Jens Axboe Cc: "linux-kernel@vger.kernel.org" In-Reply-To: <20091103183235.GD8742@kernel.dk> References: <20091103183235.GD8742@kernel.dk> Content-Type: text/plain Organization: intel.com Date: Wed, 04 Nov 2009 09:21:30 +0800 Message-Id: <1257297690.3819.256.camel@alexs-hp.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 (2.26.1-2.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yes, the performance recovered with this patch on 32-rc6 kernel. On Wed, 2009-11-04 at 02:32 +0800, Jens Axboe wrote: > On Tue, Nov 03 2009, Shi, Alex wrote: > > I found the kernel building will have about 20%~ 30% regressions on > > our NHM machines. My kernel build do the following things 15 times: > > > > make mrproper; echo \"3\">/proc/sys/vm/drop_caches; make defconfig; > > make -j${2timescpunumbers} > > > > > > > > Bisect found it is due to the commitment: > > > > commit a6151c3a5c8e1ff5a28450bc8d6a99a2a0add0a7 > > I looked over that commit and found one typo, can you check with this > patch applied? > > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c > index 069a610..5802e32 100644 > --- a/block/cfq-iosched.c > +++ b/block/cfq-iosched.c > @@ -2051,7 +2051,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, > * it's a metadata request and the current queue is doing regular IO. > */ > if (rq_is_meta(rq) && !cfqq->meta_pending) > - return false; > + return true; > > /* > * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. >