From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756568AbXH0Xvt (ORCPT ); Mon, 27 Aug 2007 19:51:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753816AbXH0Xvk (ORCPT ); Mon, 27 Aug 2007 19:51:40 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:42305 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753806AbXH0Xvj (ORCPT ); Mon, 27 Aug 2007 19:51:39 -0400 Date: Mon, 27 Aug 2007 16:51:26 -0700 From: Andrew Morton To: Christoph Lameter Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Pekka Enberg Subject: Re: [patch 0/6] Per cpu structures for SLUB Message-Id: <20070827165126.a1a9846b.akpm@linux-foundation.org> In-Reply-To: References: <20070823064653.081843729@sgi.com> <20070824143848.a1ecb6bc.akpm@linux-foundation.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 27 Aug 2007 11:50:10 -0700 (PDT) Christoph Lameter wrote: > On Fri, 24 Aug 2007, Andrew Morton wrote: > > > I'm struggling a bit to understand these numbers. Bigger is better, I > > assume? In what units are these numbers? > > No less is better. These are cycle counts. Hmmm... We discussed these > cycle counts so much in the last week that I forgot to mention that. > > > > Page allocator pass through > > > --------------------------- > > > There is a significant difference in the columns marked with a * because > > > of the way that allocations for page sized objects are handled. > > > > OK, but what happened to the third pair of columns (Concurrent Alloc, > > Kmalloc) for 1024 and 2048-byte allocations? They seem to have become > > significantly slower? > > There is a significant performance increase there. That is the main point > of the patch. > > > Thanks for running the numbers, but it's still a bit hard to work out > > whether these changes are an aggregate benefit? > > There is a drawback because of the additional code introduced in the fast > path. However, the regular kmalloc case shows improvements throughout. > This is in particular of importance for SMP systems. We see an improvement > even for 2 processors. umm, OK. When you have time, could you please whizz up a clearer changelog for this one?