Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754071Ab0KLChi (ORCPT ); Thu, 11 Nov 2010 21:37:38 -0500 Received: from x35.xmailserver.org ([64.71.152.41]:59091 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753064Ab0KLChh (ORCPT ); Thu, 11 Nov 2010 21:37:37 -0500 X-AuthUser: davidel@xmailserver.org Date: Thu, 11 Nov 2010 18:35:51 -0800 (PST) From: Davide Libenzi X-X-Sender: davide@davide-lnx1 To: Thomas Gleixner cc: Kyle Moffett , Alexander Shishkin , Valdis.Kletnieks@vt.edu, LKML , John Stultz , Andrew Morton , "H. Peter Anvin" , Kay Sievers , Greg KH , Chris Friesen , Linus Torvalds , "Kirill A. Shutemov" Subject: Re: [PATCHv6 0/7] system time changes notification In-Reply-To: Message-ID: References: <1289503802-22444-1-git-send-email-virtuoso@slind.org> <22542.1289507293@localhost> <20101111205123.GC10585@shisha.kicks-ass.net> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 40 On Thu, 11 Nov 2010, Thomas Gleixner wrote: > > [...] > > > > This would also enable the folks who want to support things like PHY > > hardware clocks (for very-low-latency ethernet timestamping). It > > would resolve the enumeration problem; instead of 0, 1, 2, ... as > > constants, they would show up in sysfs and be open()able. Ideally you > > would be able to set up ntpd to slew the "realtime" clock by following > > a particular hardware clock, or vice versa. > > There are other plans for the various interesting clocks floating > around which look pretty good. > > But what you folks really want for this stuff is an extension to > timerfd as you want to be able to poll, right? > > So what about the following: > > Add a new flag TDF_NOTIFY_CLOCK_WAS_SET to the timerfd flags. Now this > flag adds the timer to a separate list, which gets woken up when the > clock is set. What chu talkin bout Willis? :) This borders the interface multiplexing, if I got your idea correctly. Timerfd is about expiring private timers, not about getting out notifications about system-wide time changes. I understand your concerns about that code, but please do not use timerfd as a sacrificial mule to fit something which IMO does not belong there. - Davide -- 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/