Re: Large (8M) cache vs. dual-core CPUs

On Wed, Apr 26, 2006 at 10:17:58AM -0500, Scott Marlowe wrote:
> On Tue, 2006-04-25 at 18:55, Jim C. Nasby wrote:
> > On Tue, Apr 25, 2006 at 01:33:38PM -0500, Scott Marlowe wrote:
> > > On Tue, 2006-04-25 at 13:14, Bill Moran wrote:
> > > > I've been given the task of making some hardware recommendations for
> > > > the next round of server purchases. The machines to be purchased
> > > > will be running FreeBSD & PostgreSQL.
> > > >
> > > > Where I'm stuck is in deciding whether we want to go with dual-core
> > > > pentiums with 2M cache, or with HT pentiums with 8M cache.
> > >
> > > Given a choice between those two processors, I'd choose the AMD 64 x 2
> > > CPU. It's a significantly better processor than either of the Intel
> > > choices. And if you get the HT processor, you might as well turn of HT
> > > on a PostgreSQL machine. I've yet to see it make postgresql run faster,
> > > but I've certainly seen HT make it run slower.
> >
> > Actually, believe it or not, a coworker just saw HT double the
> > performance of pgbench on his desktop machine. Granted, not really a
> > representative test case, but it still blew my mind. This was with a
> > database that fit in his 1G of memory, and running windows XP. Both
> > cases were newly minted pgbench databases with a scale of 40. Testing
> > was 40 connections and 100 transactions. With HT he saw 47.6 TPS,
> > without it was 21.1.
> >
> > I actually had IT build put w2k3 server on a HT box specifically so I
> > could do more testing.
>
> Just to clarify, this is PostgreSQL on Windows, right?
>
> I wonder if the latest Linux kernel can do that well... I'm guessing
> that the kernel scheduler in Windows has had a lot of work to make it
> good at scheduling on a HT architecture than the linux kernel has.

Yes, this is on Windows XP. Larry might also have a HT box with some
other OS on it we can check with (though I suspect that maybe that's
been beaten to death...)
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461