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Subject: Re: x86-tip tsc/tick gripage
From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
        "Paul E. McKenney" <paulmck@us.ibm.com>,
        LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>,
        Frederic Weisbecker <fweisbec@gmail.com>
Date: Wed, 26 Apr 2017 14:30:36 +0200
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On Wed, 2017-04-26 at 13:39 +0200, Mike Galbraith wrote:
> On Wed, 2017-04-26 at 12:26 +0200, Peter Zijlstra wrote:
> > On Wed, Apr 26, 2017 at 10:57:42AM +0200, Mike Galbraith wrote:
> > 
> > > Both still lose their TSC.
> > > 
> > > [   11.982468] tsc: Refined TSC clocksource calibration: 2260.999 MHz
> > > [   11.994275] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x20974a4d8bb, max_idle_ns: 440795246623 ns
> > > [   13.064172] clocksource: Switched to clocksource tsc
> > > [  240.247851] clocksource: timekeeping watchdog on CPU23: Marking clocksource 'tsc' as unstable because the skew is too large:
> > > [  240.462501] clocksource:                       'tsc' cs_now: 108fe5be09f cs_last: b90a6a0676 mask: ffffffffffffffff
> > > [  240.675057] tsc: Marking TSC unstable due to clocksource watchdog
> > 
> > 
> > And they didn't use to? We don't typically write to TSC or TSC_ADJUST
> > and thus would not cause such behaviour.
> 
> Nope.

DL980 seems perfectly happy with master.today.. so off we go.