From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761352AbXGJQhd (ORCPT ); Tue, 10 Jul 2007 12:37:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755348AbXGJQh1 (ORCPT ); Tue, 10 Jul 2007 12:37:27 -0400 Received: from 81-174-11-161.static.ngi.it ([81.174.11.161]:48587 "EHLO mail.enneenne.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754259AbXGJQh0 (ORCPT ); Tue, 10 Jul 2007 12:37:26 -0400 Date: Tue, 10 Jul 2007 18:38:39 +0200 From: Rodolfo Giometti To: David Woodhouse Cc: linux-kernel@vger.kernel.org, Andrew Morton Message-ID: <20070710163839.GI32503@enneenne.com> References: <20070629150813.GM13886@enneenne.com> <1183132548.1170.360.camel@pmac.infradead.org> <20070629163422.GP13886@enneenne.com> <1183135253.17622.5.camel@shinybook.infradead.org> <20070630171340.GT13886@enneenne.com> <1183291392.2828.17.camel@shinybook.infradead.org> <20070703094831.GA13413@enneenne.com> <1183468191.29081.17.camel@shinybook.infradead.org> <20070709131924.GM11451@enneenne.com> <1184083547.32628.4.camel@pmac.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1184083547.32628.4.camel@pmac.infradead.org> Organization: GNU/Linux Device Drivers, Embedded Systems and Courses X-PGP-Key: gpg --keyserver keyserver.linux.it --recv-keys D25A5633 User-Agent: Mutt/1.5.16 (2007-06-11) X-SA-Exim-Connect-IP: 192.168.32.1 X-SA-Exim-Mail-From: giometti@enneenne.com Subject: Re: [PATCH] LinuxPPS (with new syscalls API) - new version X-SA-Exim-Version: 4.2 (built Thu, 03 Mar 2005 10:44:12 +0100) X-SA-Exim-Scanned: Yes (on mail.enneenne.com) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 10, 2007 at 05:05:47PM +0100, David Woodhouse wrote: > > I'm sure the version with 'volatile' will also be broken then. Sounds > like the right answer is to fix the locking. But wish avoiding locking at all since this may delay the time stamp recording. We (the LinuxPPS guys) niticed that just a single instruction my degrade the time setting about 50%! I avoid locking just using a pointer and setting it to a dummy structure when not used... is that wrong? :-o Ciao, Rodolfo -- GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@gnudd.com Embedded Systems giometti@linux.it UNIX programming phone: +39 349 2432127