Re: Scaling noise

Jörn Engel
2003-09-03T16:03:56Z

On Wed, 3 September 2003 08:10:33 -0700, Martin J. Bligh wrote:
>
> > multi node yes, numa not much and where numa-like systems are being used
> > they are being used for message passing not as a fake big pc.
> >
> > Numa is valuable because
> > - It makes some things go faster without having to rewrite them
> > - It lets you partition a large box into several effective small ones
> > cutting maintenance
> > - It lets you partition a large box into several effective small ones
> > so you can avoid buying two software licenses for expensive toys
> >
> > if you actually care enough about performance to write the code to do
> > the job then its value is rather questionable. There are exceptions as
> > with anything else.
>
> The real core use of NUMA is to run one really big app on one machine,
> where it's hard to split it across a cluster. You just can't build an
> SMP box big enough for some of these things.

This "hard to split" is usually caused by memory use instead of cpu
use, right?

I don't see a big problem scaling number crunchers over a cluster, but
a process with a working set >64GB cannot be split between 4GB
machines easily.

Jörn

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