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From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Alex Shi <alex.shi@intel.com>,
	hpa@linux.intel.com, tim.c.chen@linux.intel.com,
	linux-kernel@vger.kernel.org, andi.kleen@intel.com,
	mingo@elte.hu
Subject: Re: [URGENT rfc patch 0/3] tsc clocksource bug fix
Date: Fri, 5 Jul 2013 23:50:05 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.02.1307052345330.32106@ionos.tec.linutronix.de> (raw)
In-Reply-To: <20130705212235.GU23916@twins.programming.kicks-ass.net>

On Fri, 5 Jul 2013, Peter Zijlstra wrote:
> On Fri, Jul 05, 2013 at 05:24:09PM +0200, Thomas Gleixner wrote:
> > See arch/x86/kernel/tsc.c
> > 
> > We disable the watchdog for the TSC when tsc_clocksource_reliable is
> > set.
> > 
> > tsc_clocksource_reliable is set when:
> > 
> >  - you add tsc=reliable to the kernel command line
> 
> Ah, I didn't know about that one, useful.
> 
> >  - boot_cpu_has(X86_FEATURE_TSC_RELIABLE)
> >  
> >    X86_FEATURE_TSC_RELIABLE is a software flag, set by vmware and
> >    moorsetown. So all other machines keep the watchdog enabled.
> 
> Right.. I knew it was enabled on my machines even though they normally
> have usable TSC.

Yeah, but our well justified paranoia still prevents us from trusting
these CPU flags. Maybe some day BIOS is going to be replaced by
something useful. You know: Hope springs eternal....





  reply	other threads:[~2013-07-05 21:50 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-04  5:34 [URGENT rfc patch 0/3] tsc clocksource bug fix Alex Shi
2013-07-04  5:34 ` [PATCH 1/3] clocksource: clean up clocksource_select Alex Shi
2013-07-04  9:57   ` Thomas Gleixner
2013-07-04 10:21     ` Alex Shi
2013-07-04 10:27       ` Thomas Gleixner
2013-07-05  1:22         ` Alex Shi
2013-07-04  5:34 ` [PATCH 2/3] clockesource: set override clocksource Alex Shi
2013-07-04 10:23   ` Thomas Gleixner
2013-07-04  5:34 ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-04 10:55   ` Thomas Gleixner
2013-07-04 13:04     ` Thomas Gleixner
2013-07-04 20:46       ` [PATCH] clocksource: Reselect clocksource when watchdog validated Thomas Gleixner
2013-07-05  1:38         ` Alex Shi
2013-07-05  9:13         ` [tip:timers/core] clocksource: Reselect clocksource when watchdog validated high-res capability tip-bot for Thomas Gleixner
2013-07-05  2:48       ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-05  5:41         ` Thomas Gleixner
2013-07-05  6:44           ` Alex Shi
2013-07-04  7:58 ` [URGENT rfc patch 0/3] tsc clocksource bug fix Peter Zijlstra
2013-07-04  8:13   ` Alex Shi
2013-07-05 14:23   ` Frederic Weisbecker
2013-07-05 14:38     ` Peter Zijlstra
2013-07-05 15:24       ` Thomas Gleixner
2013-07-05 21:22         ` Peter Zijlstra
2013-07-05 21:50           ` Thomas Gleixner [this message]
2013-07-05 21:58             ` Borislav Petkov
2013-07-05 22:17               ` Thomas Gleixner
2013-07-06  8:37                 ` Borislav Petkov
2013-07-06 10:50             ` Peter Zijlstra
2013-07-04 11:00 ` Thomas Gleixner
2013-07-04 18:11   ` Davidlohr Bueso
2013-07-04 20:27     ` Thomas Gleixner
2013-07-05  1:12       ` Alex Shi
2013-07-05  5:58         ` Thomas Gleixner
2013-07-05  6:28           ` Alex Shi

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