linux-kernel - Re: [PATCH 1/2] VMware guest detection for x86 and x86-64

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Message-Id: <E1KifeK-0002Qg-00@calista.eckenfels.net>
Date:	Thu, 25 Sep 2008 03:28:08 +0200
From:	Bernd Eckenfels <ecki@...a.inka.de>
To:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] VMware guest detection for x86 and x86-64

In article <20080925002333.GD21049@...tp.cn.ibm.com> you wrote:
> Oh I never heard about this. I've been using several VMware VMs
> (combined RHEL and SLES and Debian) but haven't seen such
> issue. What's the symptom?

Having a high HZ slows down VMs and also leads to tick loss (time drift). HZ
100 or 250 is recommended by most Vendors.

I think some distributions use the reduced HZ value by default anyway, so
you might never had a problem with this.

It is also only a problem with system load and timekeeping, which is not
always obvious. When running a lot of nearly idle VM Guests you might see
it.

Gruss
Bernd
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