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Date: Wed, 25 May 2005 16:08:49 -0700
From: Kris Kennaway <kris@obsecurity.org>
To: Jon Dama <jd@ugcs.caltech.edu>
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Cc: Bjarne Wichmann Petersen <freebsd.nospam@mekanix.dk>,
	Mike Jakubik <mikej@rogers.com>,
	Matthias Buelow <mkb@incubus.de>, freebsd-stable@freebsd.org,
	Kris Kennaway <kris@obsecurity.org>
Subject: Re: Performance of 4.x vs 5.x (Re: Lifetime of FreeBSD branches)
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On Wed, May 25, 2005 at 04:02:58PM -0700, Jon Dama wrote:
> It's different, yes.  But the trouble is that you need a controlled
> interrupt source--i.e., you have to have some concept of when an "event"
> might have been handled (were it not for such and such activity).
>=20
> I posit that without that counterfactual talking about PREEMPTION is
> meaningless.
>=20
> The technique I mentioned--measuring and comparing the jitter was intended
> to quash measuring the performance of the network stack itself.
>=20
> Do you have an idea how you can pose that counterfactual in a synthetic
> arrangement more closely connected with the problem at hand?

Nope..that's why I said it was a hard thing to study.  Well-controlled
benchmarking of FreeBSD is always welcome, so please feel free to
proceed with your tests and let us know of anything interesting you
identify.

Kris

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