Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262050AbVDFAYN (ORCPT ); Tue, 5 Apr 2005 20:24:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262045AbVDFAYM (ORCPT ); Tue, 5 Apr 2005 20:24:12 -0400 Received: from palrel11.hp.com ([156.153.255.246]:59278 "EHLO palrel11.hp.com") by vger.kernel.org with ESMTP id S262043AbVDFAYE (ORCPT ); Tue, 5 Apr 2005 20:24:04 -0400 From: David Mosberger MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16979.11287.36091.610287@napali.hpl.hp.com> Date: Tue, 5 Apr 2005 17:23:51 -0700 To: Christoph Lameter Cc: davidm@hpl.hp.com, Andi Kleen , Christoph Lameter , Denis Vlasenko , Dave Hansen , Andrew Morton , Linux Kernel Mailing List , Mel Gorman , linux-ia64@vger.kernel.org, Jens.Maurer@gmx.net Subject: Re: [PATCH] add a clear_pages function to clear pages of higher order In-Reply-To: References: <200503111008.12134.vda@port.imtp.ilyichevsk.odessa.ua> <200503181154.37414.vda@port.imtp.ilyichevsk.odessa.ua> <20050318192808.GB38053@muc.de> <16963.2075.713737.485070@napali.hpl.hp.com> X-Mailer: VM 7.19 under Emacs 21.4.1 Reply-To: davidm@hpl.hp.com X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1600 Lines: 33 >>>>> On Tue, 5 Apr 2005 17:15:53 -0700 (PDT), Christoph Lameter said: Christoph> On Thu, 24 Mar 2005, David Mosberger wrote: >> That's definitely the case. See my earlier post on this topic: >> http://www.gelato.unsw.edu.au/linux-ia64/0409/11012.html >> Unfortunately, nobody reported any results for larger machines >> and/or more interesting workloads, so the patch is in limbo at >> this time. Clearly, if the CPU that's clearing the page is >> likely to use that same page soon after, it'd be useful to use >> temporal stores. Christoph> Here are some numbers using lmbench of temporal writes Christoph> vs. non temporal writes on ia64 (8p machine but lmbench Christoph> run only for one load). There seems to be some benefit Christoph> for fork/exec but overall this does not seem to be a Christoph> clear win. I suspect that the distinction between Christoph> temporal vs. nontemporal writes is be more beneficial on Christoph> machines with smaller pagesizes since the likelyhood that Christoph> most cachelines of a page are used soon is increased and Christoph> therefore hot zeroing is more beneficial. What LMbench test other than fork/exec would you have expected to be affected by this? LMbench is not a good benchmark for this (remember: it's a _micro_ benchmark). --david - 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/