From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1957002AbdDZIXZ (ORCPT <rfc822;w@1wt.eu>);
        Wed, 26 Apr 2017 04:23:25 -0400
Received: from mail-wr0-f196.google.com ([209.85.128.196]:32866 "EHLO
        mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1956867AbdDZIVn (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 26 Apr 2017 04:21:43 -0400
Date: Wed, 26 Apr 2017 10:21:37 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Mike Galbraith <efault@gmx.de>,
        "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: x86-tip tsc/tick gripage
Message-ID: <20170426082137.koj7q3ftfqw3o22u@gmail.com>
References: <1493193739.4412.30.camel@gmx.de>
 <1493194602.21594.4.camel@gmx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1493194602.21594.4.camel@gmx.de>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


* Mike Galbraith <efault@gmx.de> wrote:

> On Wed, 2017-04-26 at 10:02 +0200, Mike Galbraith wrote:
> 
> > tip v4.11-rc8-893-g8ec9e12aff06, trusty ole 8 socket (X7560) DL980 G7
> 
> Ew, DL980 then turned into unhappy RCU camper.
> 
> [  316.980923] basemono: 316956000000 ts->next_tick: 316380000000 dev->next_event: 316956005002
> [  689.893122] INFO: rcu_sched detected stalls on CPUs/tasks:

Probably RCU unrelated.

I have temporarily removed the current timers/urgent lineup from -tip:

 098991fccfc7: nohz: Print more debug info in tick_nohz_stop_sched_tick()
 22aa2ad45fd8: tick: Make sure tick timer is active when bypassing reprogramming
 d58bd60c773d: nohz: Fix again collision between tick and other hrtimers

... and have reintegrated tip:master, so it should be back to working I think.

Does this solve the warning and the RCU stalls on your boxes?

Thanks,

	Ingo