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

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.