From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756157AbbFBJVh (ORCPT ); Tue, 2 Jun 2015 05:21:37 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:35990 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752501AbbFBJV1 (ORCPT ); Tue, 2 Jun 2015 05:21:27 -0400 Date: Tue, 2 Jun 2015 11:21:19 +0200 From: Peter Zijlstra To: Ingo Molnar Cc: John Stultz , lkml , Prarit Bhargava , Daniel Bristot de Oliveira , Richard Cochran , Jan Kara , Jiri Bohac , Thomas Gleixner , Ingo Molnar , Shuah Khan Subject: Re: [RFC][PATCH 4/4] time: Do leapsecond adjustment in gettime fastpaths Message-ID: <20150602092119.GX19282@twins.programming.kicks-ass.net> References: <1432931068-4980-1-git-send-email-john.stultz@linaro.org> <1432931068-4980-5-git-send-email-john.stultz@linaro.org> <20150602090154.GA2590@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150602090154.GA2590@gmail.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 02, 2015 at 11:01:54AM +0200, Ingo Molnar wrote: > > Currently, leapsecond adjustments are done at tick time. > > > > As a result, the leapsecond was applied at the first timer > > tick *after* the leapsecond (~1-10ms late depending on HZ), > > rather then exactly on the second edge. So why not program a hrtimer to expire at the exact right time? Then even the VDSO gets its time 'right' and you avoid touching all the fast paths.