From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753108AbdA3LKF (ORCPT ); Mon, 30 Jan 2017 06:10:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:28270 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752552AbdA3LHV (ORCPT ); Mon, 30 Jan 2017 06:07:21 -0500 From: Vitaly Kuznetsov To: devel@linuxdriverproject.org Cc: linux-kernel@vger.kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , John Stultz , Thomas Gleixner , Alex Ng , Stephen Hemminger , Radim Krcmar , Olaf Hering , Richard Cochran Subject: [PATCH v5 0/3] hv_util: adjust system time smoothly Date: Mon, 30 Jan 2017 12:07:13 +0100 Message-Id: <20170130110716.16795-1-vkuznets@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 30 Jan 2017 11:07:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With TimeSync version 4 protocol support we started updating system time continuously through the whole lifetime of Hyper-V guests. Every 5 seconds there is a time sample from the host which triggers do_settimeofday[64](). While the time from the host is very accurate such adjustments may cause issues: - Time is jumping forward and backward, some applications may misbehave. - In case an NTP server runs in parallel and uses something else for time sync (network, PTP,...) system time will never converge. - Systemd starts annoying you by printing "Time has been changed" every 5 seconds to the system log. Instead of doing in-kernel time adjustments offload the work to an NTP client by exposing TimeSync messages as a PTP device. Users may now decide what they want to use as a source. Changes since v4: - Rebase to the current char-misc-next tree [K. Y.] - Drop const qualifier from ptp_hyperv_info [kbuild test robot] - Implement .getcrosststamp() callback [Radim Krcmar] Vitaly Kuznetsov (3): hv_util: switch to using timespec64 hv: export current Hyper-V clocksource hv_utils: implement Hyper-V PTP source arch/x86/hyperv/hv_init.c | 13 ++- arch/x86/include/asm/mshyperv.h | 3 + drivers/hv/hv_util.c | 183 +++++++++++++++++++++++++++++++++------- 3 files changed, 166 insertions(+), 33 deletions(-) -- 2.9.3