Re: Wierd context-switching issue on Xeon

On Mon, 19 Apr 2004, Bruce Momjian wrote:

> Josh Berkus wrote:
> > Tom,
> >
> > > So in the short term I think we have to tell people that Xeon MP is not
> > > the most desirable SMP platform to run Postgres on. (Josh thinks that
> > > the specific motherboard chipset being used in these machines might
> > > share some of the blame too. I don't have any evidence for or against
> > > that idea, but it's certainly possible.)
> >
> > I have 3 reasons for thinking this:
> > 1) the ServerWorks chipset is present in the fully documented cases that we
> > have of this problem so far. This is notable becuase the SW is notorious
> > for poor manufacturing quality, so much so that the company that made them is
> > currently in receivership. These chips were so bad that Dell was forced to
> > recall several hundred of it's 2650's, where the motherboards caught fire!
> > 2) the main defect of the SW is the NorthBridge, which could conceivably
> > adversely affect traffic between RAM and the processor cache.
> > 3) XeonMP is a very popular platform thanks to Dell, and we are not seeing
> > more problem reports than we are.
> >
> > The other thing I'd like your comment on, Tom, is that Dirk appears to have
> > reported that when he installed a non-bigmem kernel, the issue went away.
>
> I have BSD on a SuperMicro dual Xeon, so if folks want another
> hardware/OS combination to test, I can give out logins to my machine.

I can probably do some nighttime testing on a dual 2800MHz non-MP Xeon
machine as well. It's a Dell 2600 series machine and very fast. It has
the moderately fast 533MHz FSB so may not have as many problems as the MP
type CPUs seem to be having.