From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261647AbULIWsm (ORCPT ); Thu, 9 Dec 2004 17:48:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261651AbULIWsm (ORCPT ); Thu, 9 Dec 2004 17:48:42 -0500 Received: from fw.osdl.org ([65.172.181.6]:35255 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261647AbULIWsj (ORCPT ); Thu, 9 Dec 2004 17:48:39 -0500 Date: Thu, 9 Dec 2004 14:52:37 -0800 From: Andrew Morton To: Christoph Lameter Cc: hugh@veritas.com, torvalds@osdl.org, benh@kernel.crashing.org, nickpiggin@yahoo.com.au, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V12: rss tasklist vs sloppy rss Message-Id: <20041209145237.353f5c71.akpm@osdl.org> In-Reply-To: References: X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i586-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 Christoph Lameter wrote: > > On Thu, 9 Dec 2004, Hugh Dickins wrote: > > > How do the scalability figures compare if you omit patch 7/7 i.e. revert > > the per-task rss complications you added in for Linus? I remain a fan > > of sloppy rss, which you earlier showed to be accurate enough (I'd say), > > though I guess should be checked on other architectures than your ia64. > > I can't see the point of all that added ugliness for numbers which don't > > need to be precise - but perhaps there's no way of rearranging fields, > > and the point at which mm->(anon_)rss is updated (near up of mmap_sem?), > > to avoid destructive cacheline bounce. What I'm asking is, do you have > > numbers to support 7/7? Perhaps it's the fact you showed up to 512 cpus > > this time, but only up to 32 with sloppy rss? The ratios do look better > > with the latest, but the numbers are altogether lower so we don't know. > > Here is a full set of numbers for sloppy and tasklist. Yes, but that only tests the thing-which-you're-trying-to-improve. We also need to work out the impact of that tasklist walk on other people's worst cases. > sloppy (2.6.10-bk14-rss-sloppy-prefault): It would be helpful if you could generate a breif summary of benchmarking results as well as dumping the raw numbers, please.