From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272521AbTGaQGb (ORCPT ); Thu, 31 Jul 2003 12:06:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272516AbTGaQGb (ORCPT ); Thu, 31 Jul 2003 12:06:31 -0400 Received: from pc1-cwma1-5-cust4.swan.cable.ntl.com ([80.5.120.4]:34702 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S274821AbTGaQFl (ORCPT ); Thu, 31 Jul 2003 12:05:41 -0400 Subject: Re: TSCs are a no-no on i386 From: Alan Cox To: Jamie Lokier Cc: Petr Vandrovec , lkml In-Reply-To: <20030731151020.GF6410@mail.jlokier.co.uk> References: <20030730135623.GA1873@lug-owl.de> <20030730181006.GB21734@fs.tum.de> <20030730183033.GA970@matchmail.com> <20030730184529.GE21734@fs.tum.de> <20030730202822.GG1873@lug-owl.de> <20030730215032.GA18892@vana.vc.cvut.cz> <1059606394.10505.24.camel@dhcp22.swansea.linux.org.uk> <20030731151020.GF6410@mail.jlokier.co.uk> Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: Message-Id: <1059667304.16608.47.camel@dhcp22.swansea.linux.org.uk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-5) Date: 31 Jul 2003 17:01:45 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Iau, 2003-07-31 at 16:10, Jamie Lokier wrote: > > And if the byte you are looking at was patched by another thread you've > > blown it. Your emulation can only be so good 8) People do stuff like > > patching instructions under software decode as a robustness check - its > > normally pretty amusing > > On a uniprocessor 386, this is not a problem. Just disable preemption > in the kernel decoder. Wrong again. Thats a common myth but you see I can put the instruction on a page so that its executed from a page I just did a read() into in another process. If I'm really bored I'll use O_DIRECT but thats mostly for makign life really bad for non cache coherent setups 8)