From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: SLUB performance regression vs SLAB Date: Fri, 05 Oct 2007 22:32:00 +0200 Message-ID: <1191616320.5838.26.camel@lappy> References: <20071004183224.GA8641@linux.intel.com> <20071004192824.GA9852@linux.intel.com> <20071004.135537.39158051.davem@davemloft.net> <470554D9.2050505@redhat.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: David Miller , willy@linux.intel.com, clameter@sgi.com, nickpiggin@yahoo.com.au, hch@lst.de, mel@skynet.ie, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, dgc@sgi.com, jens.axboe@oracle.com, suresh.b.siddha@intel.com To: Chuck Ebbert Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:52323 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761008AbXJEUcV (ORCPT ); Fri, 5 Oct 2007 16:32:21 -0400 In-Reply-To: <470554D9.2050505@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, 2007-10-04 at 17:02 -0400, Chuck Ebbert wrote: > On 10/04/2007 04:55 PM, David Miller wrote: > > > > Anything, I do mean anything, can be simulated using small test > > programs. > > How do you simulate reading 100TB of data spread across 3000 disks, > selecting 10% of it using some criterion, then sorting and summarizing > the result? Focus on the slab allocator usage, instrument it, record a trace, generate a statistical model that matches, and write a small programm/kernel module that has the same allocation pattern. Then verify this statistical workload still shows the same performance difference. Easy: no Doable: yes