Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752278AbbG2MaN (ORCPT ); Wed, 29 Jul 2015 08:30:13 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:35595 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750784AbbG2MaK (ORCPT ); Wed, 29 Jul 2015 08:30:10 -0400 Date: Wed, 29 Jul 2015 14:30:05 +0200 From: Richard Cochran To: Thomas Gleixner Cc: John Stultz , Christopher Hall , Ingo Molnar , Jeff Kirsher , john.ronciak@intel.com, "H. Peter Anvin" , "x86@kernel.org" , lkml , netdev@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH 1/5] Add functions producing system time given a backing counter value Message-ID: <20150729123005.GB16880@localhost.localdomain> References: <1438044416-15588-1-git-send-email-christopher.s.hall@intel.com> <1438044416-15588-2-git-send-email-christopher.s.hall@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1118 Lines: 29 On Wed, Jul 29, 2015 at 12:23:27PM +0200, Thomas Gleixner wrote: > > Something like the below untested patch should be all we need for PTP > > to be as precise as possible. Yes, that is as good as it can be. The code protects against concurrent NTP adjustments, and the PTP driver will have to block changes to its clock during the ioctl. > > I don't know whether we need functionality to convert arbitrary > > timestamps at all, but if we really need them then they are going to > > be pretty simple and explicitely not precise for anything else than > > clock monotonic raw. But that's a different story. > > > > Lets concentrate on PTP first and talk about the other stuff once we > > settled the use case which actually has a precision requirement. The PTP ioctl only needs the REALTIME value, and so the MONO-RAW bit could be dropped for now. Thanks, Richard -- 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/