Date: Mon, 25 Aug 2008 11:22:44 -0700
From: Arjan van de Ven <arjan@infradead.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Dave Jones <davej@codemonkey.org.uk>,
       Peter Zijlstra <peterz@infradead.org>,
       linux-kernel <linux-kernel@vger.kernel.org>, cpufreq@vger.kernel.org,
       Alok Kataria <akataria@vmware.com>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [BUG] cpufreq: constant cpu_khz
Message-ID: <20080825112244.34b2fe67@infradead.org>
In-Reply-To: <20080825175712.GA10848@elte.hu>
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	<20080825123926.GC8663@elte.hu>
	<20080825175547.GA26131@codemonkey.org.uk>
	<20080825175712.GA10848@elte.hu>
Organization: Intel
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On Mon, 25 Aug 2008 19:57:12 +0200
Ingo Molnar <mingo@elte.hu> wrote:

> 
> * Dave Jones <davej@codemonkey.org.uk> wrote:
> 
> >  > hm, that too is due to the tsc.c unification - Alok Cc:-ed.
> >  > Applied your fix to x86/urgent.
> > 
> > ACKed-by: Dave Jones <davej@redhat.com>
> > 
> > Good catch Peter.  I'm puzzled how that bug was latent on 64bit for
> > so long with no-one realising though.
> 
> i think it's the combination of these two factors:
> 
>  - bootup frequently is typically full-speed, so we calibrate things 
>    right
> 
>  - cpufreq events are relatively slow-scale - and when they trigger
> the system is definitely not under load. So how precisely the
> scheduler functions isnt all that important in such scenarios -
> there's tons of CPU power available.
> 

- many many of the 64 bit capable cpus are constant-tsc anyway

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