On Mon, Dec 18, 2006 at 05:44:45PM +1100, Carl Brewer wrote:
> I'm curious to know how effective it is on NetBSD?

Not very. Depending on the workload of you system the overhead from the
locking in an SMP kernel might not be worth the performance gain.

> I have a couple of RHEL servers that, when running top, show
> multiple cpu's as the thread engines (I assume?), ...

The two virtual CPUs provided by HT appear as two physical CPUs to the
operating system.

> ... but top on NetBSD 3.1 doesn't show this.

Are you using the "GENERIC.MPACPI" kernel or a kernel based on that
configuration? Other kernels will not utilize HT.

> I'm looking at deploying one of these as a zope/plone server
> with a bunch of other stuff as well (cyrus imap, sendmail, BIND
> etc, general network server stuff) ...

I would not recomment using HT for such a workload because there will
be a lot of kernel load.

Using HT with NetBSD is most likely useful on machines which run CPU
intensive applications mostly e.g. compiling sources.

	Kind regards

-- 
Matthias Scheler                                  http://zhadum.org.uk/