From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754448AbaIZNHn (ORCPT ); Fri, 26 Sep 2014 09:07:43 -0400 Received: from mail-ig0-f177.google.com ([209.85.213.177]:38233 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789AbaIZNHl (ORCPT ); Fri, 26 Sep 2014 09:07:41 -0400 MIME-Version: 1.0 In-Reply-To: References: <1411725736-49225-1-git-send-email-huishao@microsoft.com> Date: Fri, 26 Sep 2014 14:07:40 +0100 Message-ID: Subject: Re: [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample From: Mike Surcouf To: Thomas Shao Cc: "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "driverdev-devel@linuxdriverproject.org" , Olaf Hering , Robo Bot , "jasowang@redhat.com" , KY Srinivasan , Haiyang Zhang Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> What happens when adjtimex is not present? >> Is there no kernel space function for that? >> Does this patch affect "not setting correct time on restore" or "not setting >> correct time on live migration" bug? >> > > If adjtimex is not present, then the slew time part didn't take effect. > There is a kernel space do_adjtmex, but it's only for sys call and not exposed to module. So I didn't use it in my patch. > With this patch, it will step the clock if the time drift is larger than 1 seconds, so it can solve > the issue your mentioned. And on the other hand, "setting correct time on restore" is already fixed > in other patch, which is already in upstream. > AFAIK CENTOS and RHEL stopped providing adjtimex for a while now (since V5?). Even went as far as removing references from there man page for hwclock. in V6 On CENTOS 6.5 yum provides */adjtimex Loaded plugins: fastestmirror, security Loading mirror speeds from cached hostfile * base: centosc6.centos.org * extras: centosb5.centos.org * updates: centosb6.centos.org No Matches found So the end user will have to go searching the internet rpmfind or something to install an unofficial package on an enterprise product. So by default you will be stepping time on CENTOS/RHEL 6 and above: with the result of an unstable clock. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hemlock.osuosl.org (hemlock.osuosl.org [140.211.166.133]) by ash.osuosl.org (Postfix) with ESMTP id 605711C2DDE for ; Fri, 26 Sep 2014 13:07:42 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 5CBB095F83 for ; Fri, 26 Sep 2014 13:07:42 +0000 (UTC) Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TuRVomUWk4x2 for ; Fri, 26 Sep 2014 13:07:41 +0000 (UTC) Received: from mail-ig0-f175.google.com (mail-ig0-f175.google.com [209.85.213.175]) by hemlock.osuosl.org (Postfix) with ESMTPS id 6B46895F22 for ; Fri, 26 Sep 2014 13:07:41 +0000 (UTC) Received: by mail-ig0-f175.google.com with SMTP id h18so10347699igc.2 for ; Fri, 26 Sep 2014 06:07:40 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1411725736-49225-1-git-send-email-huishao@microsoft.com> Date: Fri, 26 Sep 2014 14:07:40 +0100 Message-ID: Subject: Re: [PATCH] Drivers: hv: util: Implement Time Synchronization using host time sample From: Mike Surcouf List-Id: Linux Driver Project Developer List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: Thomas Shao Cc: Olaf Hering , "gregkh@linuxfoundation.org" , "jasowang@redhat.com" , "driverdev-devel@linuxdriverproject.org" , "linux-kernel@vger.kernel.org" , Robo Bot , Haiyang Zhang >> What happens when adjtimex is not present? >> Is there no kernel space function for that? >> Does this patch affect "not setting correct time on restore" or "not setting >> correct time on live migration" bug? >> > > If adjtimex is not present, then the slew time part didn't take effect. > There is a kernel space do_adjtmex, but it's only for sys call and not exposed to module. So I didn't use it in my patch. > With this patch, it will step the clock if the time drift is larger than 1 seconds, so it can solve > the issue your mentioned. And on the other hand, "setting correct time on restore" is already fixed > in other patch, which is already in upstream. > AFAIK CENTOS and RHEL stopped providing adjtimex for a while now (since V5?). Even went as far as removing references from there man page for hwclock. in V6 On CENTOS 6.5 yum provides */adjtimex Loaded plugins: fastestmirror, security Loading mirror speeds from cached hostfile * base: centosc6.centos.org * extras: centosb5.centos.org * updates: centosb6.centos.org No Matches found So the end user will have to go searching the internet rpmfind or something to install an unofficial package on an enterprise product. So by default you will be stepping time on CENTOS/RHEL 6 and above: with the result of an unstable clock. _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel