linux-kernel - Re: [URGENT rfc patch 0/3] tsc clocksource bug fix

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Message-ID: <20130705212235.GU23916@twins.programming.kicks-ass.net>
Date:	Fri, 5 Jul 2013 23:22:35 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Alex Shi <alex.shi@...el.com>, hpa@...ux.intel.com,
	tim.c.chen@...ux.intel.com, linux-kernel@...r.kernel.org,
	andi.kleen@...el.com, mingo@...e.hu
Subject: Re: [URGENT rfc patch 0/3] tsc clocksource bug fix

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.
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