linux-kernel - Re: [PATCH 0/3] Improve TSC as a clocksource under VMware

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Message-ID: <20081021181536.GI12825@one.firstfloor.org>
Date:	Tue, 21 Oct 2008 20:15:36 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Alok Kataria <akataria@...are.com>
Cc:	Andi Kleen <andi@...stfloor.org>, "H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	the arch/x86 maintainers <x86@...nel.org>,
	Daniel Hecht <dhecht@...are.com>
Subject: Re: [PATCH 0/3] Improve TSC as a clocksource under VMware

> FWIU from the code, even if  cpu A's TSC is just 1 tick behind that of
> cpu B, we increment the nr_wraps value.
> And the code expects that there are no wraps in TSC throughout the
> 20msec measurement window. 
> So IMO its fairly easy to fail this test.

Ok I think it would be better to enlarge the margin then to fix your
issue.

-Andi
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