Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753522AbZLCMBc (ORCPT ); Thu, 3 Dec 2009 07:01:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752557AbZLCMBc (ORCPT ); Thu, 3 Dec 2009 07:01:32 -0500 Received: from 81-174-11-161.static.ngi.it ([81.174.11.161]:57424 "EHLO mail.enneenne.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752658AbZLCMBa (ORCPT ); Thu, 3 Dec 2009 07:01:30 -0500 Date: Thu, 3 Dec 2009 13:01:30 +0100 From: Rodolfo Giometti To: "H. Peter Anvin" Cc: linux-kernel@vger.kernel.org, Andrew Morton , David Woodhouse , Dave Jones , Sam Ravnborg , Greg KH , Randy Dunlap , Kay Sievers , Alan Cox , Ingo Molnar , Michael Kerrisk , Christoph Hellwig Message-ID: <20091203120130.GD12943@gundam.enneenne.com> Mail-Followup-To: "H. Peter Anvin" , linux-kernel@vger.kernel.org, Andrew Morton , David Woodhouse , Dave Jones , Sam Ravnborg , Greg KH , Randy Dunlap , Kay Sievers , Alan Cox , Ingo Molnar , Michael Kerrisk , Christoph Hellwig References: <1259774329-29663-2-git-send-email-giometti@linux.it> <1259774329-29663-3-git-send-email-giometti@linux.it> <1259774329-29663-4-git-send-email-giometti@linux.it> <1259774329-29663-5-git-send-email-giometti@linux.it> <1259774329-29663-6-git-send-email-giometti@linux.it> <1259774329-29663-7-git-send-email-giometti@linux.it> <1259774329-29663-8-git-send-email-giometti@linux.it> <1259774329-29663-9-git-send-email-giometti@linux.it> <1259774329-29663-10-git-send-email-giometti@linux.it> <4B170204.4080604@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B170204.4080604@zytor.com> Organization: GNU/Linux Device Drivers, Embedded Systems and Courses X-PGP-Key: gpg --keyserver keyserver.linux.it --recv-keys D25A5633 User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 192.168.32.254 X-SA-Exim-Mail-From: giometti@enneenne.com Subject: Re: [PATCH 09/11] pps: low level IRQ timestamps recording. X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:14:11 +0000) X-SA-Exim-Scanned: Yes (on mail.enneenne.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1560 Lines: 37 On Wed, Dec 02, 2009 at 04:10:44PM -0800, H. Peter Anvin wrote: > On 12/02/2009 09:18 AM, Rodolfo Giometti wrote: > > Add low level IRQ timestamps recording for x86 (32 and 64 bits) > > platforms and enable UART clients in order to use it. > > > > This improves PPS precision. :) > > It also invokes getnstimeofday on every single interrupt, including ones > which have absolutely nothing to do with the PPS, and are potentially > high volume. getnstimeofday can be a fairly expensive operation, > especially if the best available clock is away from the CPU, or it > requires extensive arithmetic in order to normalize the clock value... I see, that's why I propose my patches to you: in order to have some feedbacks for better solutions. :) Can I add a IRQF_TIMESTAMP in order to ask to the system to record irq timestamps for particular irq lines? The problem is that I cannot set that flag at irq_register() time but I have to do it later... it can be a problem? Ciao, Rodolfo -- GNU/Linux Solutions e-mail: giometti@enneenne.com Linux Device Driver giometti@linux.it Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti Freelance ICT Italia - Consulente ICT Italia - www.consulenti-ict.it -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/