From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966308AbXDDFlw (ORCPT ); Wed, 4 Apr 2007 01:41:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966313AbXDDFlw (ORCPT ); Wed, 4 Apr 2007 01:41:52 -0400 Received: from terminus.zytor.com ([192.83.249.54]:55911 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966308AbXDDFlv (ORCPT ); Wed, 4 Apr 2007 01:41:51 -0400 Message-ID: <46133A5F.5000100@zytor.com> Date: Tue, 03 Apr 2007 22:40:47 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: Eric Dumazet , Ulrich Drepper , Davide Libenzi , Linux Kernel , Andrew Morton , Andi Kleen Subject: Re: getting processor numbers References: <461286D6.2040407@redhat.com> <4612ABD7.3000201@redhat.com> <4612F1F0.5070209@zytor.com> <4612F2BF.7080704@goop.org> <4612F394.6040105@zytor.com> <4613330C.1020701@cosmosbay.com> <461334B5.7070607@zytor.com> <46133609.9060402@goop.org> In-Reply-To: <46133609.9060402@goop.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jeremy Fitzhardinge wrote: > H. Peter Anvin wrote: >> Mutable data should be separated from code. I think any current CPU >> will do fine as long as they are in separate 128-byte chunks, but they >> need at least that much separation. > P4 manual says that if one processor modifies data within 2k of another > processor executing code, it will trash the entire trace cache. Yuck. Didn't realize the P4 was that sensitive. OK, so at the least we need a half-page of separation. -hpa