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From: Michael Riepe <michael-0QoEqw4nQxo@public.gmane.org>
To: Benjamin Prosnitz <b-prosnitz-angj7XTnwNpXfO9P/gJGhg@public.gmane.org>
Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: Floating point vs Integer performance
Date: Tue, 13 Mar 2007 09:16:58 +0100	[thread overview]
Message-ID: <45F65DFA.60808@mr511.de> (raw)
In-Reply-To: <1173730724.7220.5.camel@localhost>

Hi!

Benjamin Prosnitz wrote:
> I ran some benchmarks inside of KVM-12 on my system and outside of KVM
> (no virtualization on my system).  I found that floating point
> performance when running both with and without KVM was approximately the
> same, but integer performance in KVM was about 25% of what I get when
> running the test outside of KVM. These were tests using Dhrystone 2 and
> Double Precision Whetstone on a Core 2 Duo T7200 processor.
> 
> Any thoughts on why the integer and floating point performance appears
> to differ so much?

I guess it's the benchmark. In contrast to its FP counterpart, Dhrystone
doesn't crunch numbers most of the time. It also performs lots of string
operations, for example (memory access == slow).

-- 
Michael "Tired" Riepe <michael-0QoEqw4nQxo@public.gmane.org>
X-Tired: Each morning I get up I die a little

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      parent reply	other threads:[~2007-03-13  8:16 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-12 20:18 Floating point vs Integer performance Benjamin Prosnitz
2007-03-13  8:03 ` Avi Kivity
2007-03-13  8:16 ` Michael Riepe [this message]

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