From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752824AbdATOcw (ORCPT ); Fri, 20 Jan 2017 09:32:52 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57820 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103AbdATOco (ORCPT ); Fri, 20 Jan 2017 09:32:44 -0500 Date: Fri, 20 Jan 2017 15:31:43 +0100 From: Miroslav Lichvar To: Paolo Bonzini Cc: Radim Krcmar , Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Richard Cochran Subject: Re: [patch 4/5] PTP: add PTP_SYS_OFFSET emulation via cross timestamps infrastructure Message-ID: <20170120143143.GR14227@localhost> References: <20170120122025.665985919@redhat.com> <20170120122503.746158230@redhat.com> <48bb2650-ed00-ec07-31bf-8780d3ab5568@redhat.com> <20170120130711.GA27440@amt.cnet> <2d213ad9-fa40-1f1e-90a9-404764969d35@redhat.com> <20170120140216.GA1358@potion> <66e145c8-0e7c-5ae4-486b-385a058f7e05@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <66e145c8-0e7c-5ae4-486b-385a058f7e05@redhat.com> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 20 Jan 2017 14:31:46 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 20, 2017 at 03:23:08PM +0100, Paolo Bonzini wrote: > On 20/01/2017 15:02, Radim Krcmar wrote: > > Another solution would be to do just one one read and set it to all > > saples -- the difference between t[i] and t[i+2] would be 0. We are > > quite sure the just one read is enough, this hack could be even better. > > I'd be afraid of messing up chrony's stats... This should be ok. For the application it just looks as if the CPU and everything else in the path of the measurements was infinitely fast. :) -- Miroslav Lichvar