From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262177AbTFIV7R (ORCPT ); Mon, 9 Jun 2003 17:59:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262179AbTFIV7R (ORCPT ); Mon, 9 Jun 2003 17:59:17 -0400 Received: from pao-ex01.pao.digeo.com ([12.47.58.20]:56265 "EHLO pao-ex01.pao.digeo.com") by vger.kernel.org with ESMTP id S262177AbTFIV7Q (ORCPT ); Mon, 9 Jun 2003 17:59:16 -0400 Date: Mon, 9 Jun 2003 15:09:05 -0700 From: Andrew Morton To: rwhron@earthlink.net Cc: linux-kernel@vger.kernel.org Subject: Re: [BENCHMARK] 12% improvement in fork load from mm3 to mm4 Message-Id: <20030609150905.7e37bc1f.akpm@digeo.com> In-Reply-To: <20030609220255.GA8524@rushmore> References: <20030609220255.GA8524@rushmore> X-Mailer: Sylpheed version 0.9.0pre1 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 09 Jun 2003 22:12:56.0127 (UTC) FILETIME=[475604F0:01C32ED4] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org rwhron@earthlink.net wrote: > > > autoconf build test creates about 1.2 million processes in > > 35 minutes. On quad xeon, there was an improvement of > > ~ 12% between 2.5.70-mm3 and 2.5.70-mm4. > > > > Avg of 3 runs > > 2.5.70-mm3 829.0 > > 2.5.70-mm4 737.9 > > profile shows the biggest change is in do_page_fault. Well that's amusing. In mm4 I replaced the patch which runs remap_file_pages() against all prot_exec mappings with a patch which just prefaults those mappings into pagecache. The difference _should_ be that in mm3, all pte's are set up at mmap time. So -mm4 should have more pagefaults, not less. Something fishy is going on there. Makes one wonder if remap_file_pages() is successfully avoiding the minor fault.