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

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Message-ID: <20081021095002.GA5880@atrey.karlin.mff.cuni.cz>
Date:	Tue, 21 Oct 2008 11:50:03 +0200
From:	Pavel Machek <pavel@...e.cz>
To:	Alok Kataria <akataria@...are.com>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>,
	the arch/x86 maintainers <x86@...nel.org>,
	Dan Hecht <dhecht@...are.com>
Subject: Re: [PATCH 0/3] Improve TSC as a clocksource under VMware

> Hi,
> 
> This patch set makes some changes to the TSC code, so that it is always
> used as the default clocksource when running under VMware.
> The first 2 patches do the ground work of adding code to detect if we
> are running under VMware.
> The third patch adds a tsc_reliable flag which tells us that TSC is
> reliable on this system, so that we can skip some tests which can
> potentially mark TSC as unstable. Details under individual patch
> headers. 

How do you _know_ TSC is stable under VMWare? AFAICT, accesses to TSC
are not virtualized and system VMWare runs on may still use frequency
scaling, no?
									Pavel
-- 
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