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Date: Thu, 17 Jun 2004 08:52:12 -0400 (EDT)
From: Robert Watson <rwatson@freebsd.org>
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To: Petri Helenius <pete@he.iki.fi>
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cc: Brad Knowles <brad.knowles@skynet.be>
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Subject: Re: Possible Threading problem with -CURRENT / MySQL?
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On Thu, 17 Jun 2004, Petri Helenius wrote:

> Brad Knowles wrote:
>=20
> >>  - Disabling HTT
> >>  - Using ADAPTIVE_MUTEXES
> >
> >     These both sound like typical improvements, based on what I've=20
> > seen on this list.  Any ideas on when they might become the default?
> >
> HTT defaults to the BIOS setting, which I think is the logical course of=
=20
> action. I don=B4t think the OS should make assumptions the way or another=
=20
> over what the user has set in the BIOS.
> (this used not to be the case earlier, and I asked it to default to=20
> disable HTT back then)

I agree in principle; however, as a variable in this benchmark, it seems
like regardless of scheduler it's a net loss.  A question we haven't yet
answered is whether (for this workload, or other interesting workloads) it
should be a net loss, and therefore whether it's simply our support to HTT
is not yet mature enough to offer the theoretical advantage, or whether
HTT is just a bad idea. :-)

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Senior Research Scientist, McAfee Research