Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759703AbXJDRqE (ORCPT ); Thu, 4 Oct 2007 13:46:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756576AbXJDRpv (ORCPT ); Thu, 4 Oct 2007 13:45:51 -0400 Received: from mga07.intel.com ([143.182.124.22]:48837 "EHLO azsmga101.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755966AbXJDRpu (ORCPT ); Thu, 4 Oct 2007 13:45:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.21,231,1188802800"; d="scan'208";a="292733636" Date: Thu, 4 Oct 2007 11:32:24 -0700 From: Matthew Wilcox To: Christoph Lameter Cc: Nick Piggin , Christoph Hellwig , Mel Gorman , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, David Chinner , Jens Axboe Subject: Re: SLUB performance regression vs SLAB Message-ID: <20071004183224.GA8641@linux.intel.com> References: <20070919033605.785839297@sgi.com> <200709280742.38262.nickpiggin@yahoo.com.au> <200709281514.48293.nickpiggin@yahoo.com.au> <20071004161621.GO12049@parisc-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 25 On Thu, Oct 04, 2007 at 10:38:15AM -0700, Christoph Lameter wrote: > On Thu, 4 Oct 2007, Matthew Wilcox wrote: > > > So, on "a well-known OLTP benchmark which prohibits publishing absolute > > numbers" and on an x86-64 system (I don't think exactly which model > > is important), we're seeing *6.51%* performance loss on slub vs slab. > > This is with a 2.6.23-rc3 kernel. Tuning the boot parameters, as you've > > asked for before (slub_min_order=2, slub_max_order=4, slub_min_objects=8) > > gets back 0.38% of that. It's still down 6.13% over slab. > > Yeah the fastpath vs. slow path is not the issue as Siddha and I concluded > earlier. Seems that we are mainly seeing cacheline bouncing due to two > cpus accessing meta data in the same page struct. The patches in > MM that are scheduled to be merged for .24 address that issue. I > have repeatedly asked that these patches be tested. The patches were > posted months ago. I just checked with the guys who did the test. When I said -rc3, I mis-spoke; this is 2.6.23-rc3 *plus* the patches which Suresh agreed to test for you. - 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/