From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932554AbaHVRJl (ORCPT ); Fri, 22 Aug 2014 13:09:41 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:44152 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932297AbaHVRJk (ORCPT ); Fri, 22 Aug 2014 13:09:40 -0400 From: Frederic Weisbecker X-Google-Original-From: Frederic Weisbecker To: Ingo Molnar Cc: LKML , Frederic Weisbecker , Viresh Kumar , Thomas Gleixner , Preeti U Murthy Subject: [GIT PULL] nohz: Fix double clock write on idle ticks Date: Fri, 22 Aug 2014 19:09:31 +0200 Message-Id: <1408727373-8166-1-git-send-email-frederic@kernel.org> X-Mailer: git-send-email 2.1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frederic Weisbecker Ingo, Please pull the nohz/drop-double-write-v3 branch that can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git nohz/drop-double-write-v3 Although the 1st patch fixes a bug, it was a longstanding issue so that branch doesn't need to be applied in 3.17. The next merge window looks better. -- The tick reschedules itself unconditionally. It's relevant in periodic mode but not in dynticks mode where it results in spurious double clock writes and even spurious periodic behaviour for low-res case. This set fixes that: * 1st patch removes low-res periodic tick rescheduling in nohz mode. This fixes spurious periodic behaviour. * 2nd patch does the same for high-res mode. Here there is no such spurious periodic behaviour but it still spares a double clock write in some cases. --- Thanks, Frederic --- Viresh Kumar (2): nohz: Fix spurious periodic tick behaviour in low-res dynticks mode nohz: Avoid tick's double reprogramming in highres mode kernel/time/tick-sched.c | 8 ++++++++ 1 file changed, 8 insertions(+)