Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758144AbXFLCST (ORCPT ); Mon, 11 Jun 2007 22:18:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757217AbXFLCSM (ORCPT ); Mon, 11 Jun 2007 22:18:12 -0400 Received: from smtp109.mail.mud.yahoo.com ([209.191.85.219]:25956 "HELO smtp109.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757204AbXFLCSL (ORCPT ); Mon, 11 Jun 2007 22:18:11 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=af85Cv/4k9eJ7c6CcTA0upum2T5tUGZhMpslcbfkNgPKwlwLkxXYhUdZfL0TamLrV0bN3XT5W6QJdcs2gcW/8ExMs/kmzT5+6dfKLiDfflGz3JPll3RqCtcIzcX7pk6J5GNwy2nsKi9yDYNgRkxolN6UO6v7QCFnZvwRdHnKKUI= ; X-YMail-OSG: 0kLSkGMVM1mfXqyZAPKa83369L.LiQsudEihMDaCSguYbqqTKBHW9CJ1SYUxQboAwbCCsSqKNQ-- Message-ID: <466E0258.2070407@yahoo.com.au> Date: Tue, 12 Jun 2007 12:18:00 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: "H. Peter Anvin" CC: William Lee Irwin III , "Robert P. J. Day" , Satyam Sharma , Linux Kernel Mailing List , Ralf Baechle Subject: Re: why does the macro "ZERO_PAGE" take an argument? References: <4667EC18.4080904@yahoo.com.au> <4668412D.3030506@zytor.com> <20070607192911.GV6909@holomorphy.com> <46687598.2040701@zytor.com> In-Reply-To: <46687598.2040701@zytor.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1313 Lines: 33 H. Peter Anvin wrote: > William Lee Irwin III wrote: > >>Robert P. J. Day wrote: >> >>>>although it's not clear where in the source tree are the invocations >>>>that would actually make a difference to a MIPS system, which is why >>>>i've CC'ed ralf on this. i'm sure he can clear this up. :-) >> >>On Thu, Jun 07, 2007 at 10:32:29AM -0700, H. Peter Anvin wrote: >> >>>x86 could also benefit from coloured zeropages. In fact, I thought it >>>already had them (K8 wants as many as 8.) >> >>How would one demonstrate the beneficial effect of such? > > > Dean Gaudet at Transmeta did some benchmarking using SPEC. If I recall > his numbers correctly (this is from memory, mind you) on Transmeta > Efficeon, which has 2-way virtual cache tagging with hardware recovery, > zeropage coloring was a 1.5% performance improvement. I'm surprised that the benchmark made such use of zero pages so as to be worthwhile. I'm sitting on a patch which removes the zero page from the page fault fastpath completely which I'd like to try out in -mm... -- SUSE Labs, Novell Inc. - 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/