From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261936AbVGESfk (ORCPT ); Tue, 5 Jul 2005 14:35:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261924AbVGESfk (ORCPT ); Tue, 5 Jul 2005 14:35:40 -0400 Received: from mx1.redhat.com ([66.187.233.31]:3205 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S261948AbVGESa7 (ORCPT ); Tue, 5 Jul 2005 14:30:59 -0400 Message-ID: <42CAD1DF.3030405@redhat.com> Date: Tue, 05 Jul 2005 14:30:55 -0400 From: William Cohen User-Agent: Mozilla Thunderbird 1.0.2-1.3.3 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: [RFC] exit_thread() speedups in x86 process.c Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org One of the difficulties function reordering is getting useful data to figure out a reasonable order for the functions. People do guess wrong on the frequency of particular functions. Also naive ordering techniques like just ordering functions based on frequency do not work well. A North Carolina State University senior project was done to generate ordering to improve TLB and cache hit ratios using the information generated by valgrind for user-space programs: http://www.bclennox.com/cgi-bin/show.cgi?page=home Xen is running the domains (and kernels) in user-space. Would it be possible to adapt valgrind/xen to run a domain so that similar information could be collected about a particular kernel? Being able to use valgrind on the kernel could allow other analysis of the kernel code, e.g. find unwanted TLB flushes. -Will I am not subscribed to the list, so please cc me on responses.