linux-kernel - Re: [patch 13/19] GTOD: Mark TSC unusable for highres timers

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Message-Id: <200611101256.35306.ak@suse.de>
Date:	Fri, 10 Nov 2006 12:56:35 +0100
From:	Andi Kleen <ak@...e.de>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Pavel Machek <pavel@....cz>, Andrew Morton <akpm@...l.org>,
	tglx@...utronix.de, john stultz <johnstul@...ibm.com>,
	LKML <linux-kernel@...r.kernel.org>, Len Brown <lenb@...nel.org>,
	Arjan van de Ven <arjan@...radead.org>,
	Roman Zippel <zippel@...ux-m68k.org>
Subject: Re: [patch 13/19] GTOD: Mark TSC unusable for highres timers


> we could, but it would have to be almost empty right now :-) Reason: 
> even on systems that have (hardware-initialized) 'perfect' TSCs and 
> which do not support any frequency scaling or power-saving mode, our 
> current TSC initialization on SMP systems introduces a small (1-2 usecs) 
> skew.

On Intel we don't sync the TSC anymore and on most systems users seem
to be happy at least. And on multicore AMD it is drifting anyways and 
usually turned off.

-Andi
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