From owner-freebsd-current  Fri Aug 23 14:13:19 2002
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Date: Fri, 23 Aug 2002 14:13:14 -0700
From: Luigi Rizzo <rizzo@icir.org>
To: Poul-Henning Kamp <phk@critter.freebsd.dk>
Cc: current@FreeBSD.ORG
Subject: Re: how to compute the skew between TSC in SMP systems ?
Message-ID: <20020823141314.A82172@iguana.icir.org>
References: <20020823134410.A81962@iguana.icir.org> <29486.1030136549@critter.freebsd.dk>
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In-Reply-To: <29486.1030136549@critter.freebsd.dk>; from phk@critter.freebsd.dk on Fri, Aug 23, 2002 at 11:02:29PM +0200
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On Fri, Aug 23, 2002 at 11:02:29PM +0200, Poul-Henning Kamp wrote:
> In message <20020823134410.A81962@iguana.icir.org>, Luigi Rizzo writes:
> >Hi,
> >does anyone have an idea on how to determine the skew between
> >TSC content in the various processors on an SMP box ?
> 
> On i386: It cannot be reliably done.  Been there, tried that.

the problem being what, too much jitter e.g. in measurement method
that i suggested or something similar ? Do you know what
kind of error you can get away with ?

	cheers
	luigi

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