[Klug-general] A question for Kevin

[J D Freeman]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Mon, Jan 29, 2007 at 09:07:41PM +0000, Kevin Groves wrote:
> My existing cluster i four 1ghz plus one 3ghz. My benchmark gave me 
> 12-15ghz compute power equiv. For rendering  that works well as the job 
> is split into lumps of frames for each processor to run. Two such jobs 
> each at a time is good use of memory and runs well with a gig of memory 
> for each machine. Disk IO is minimal as its just sheer CPU time. Data is 
> dumped for each frame when ready.

I am inclined to think memory bus speed might be a factor, how big, I am
not sure.

> Each machine was running 300w PSU plus 450w for my 3ghz. Thats a lot of 
> power and the room heats up quite quickly with a lot of noise. All I 
> would need is five or six machines and I'm done. Perhaps running at a 
> total of 500w. Low noise and low heat.

Yes, my opteron suggestion is now low on the noise front!!

> >When you consider that there is a good chance of being able to get get a
> >quad CPU, Quad core opteron server in the next 12 months, and it
> >consuming under 1kw, you start to wonder what is the more cost effective
> >system.*
> >  
> Its all parallel processing which is the key. Even a fast machine will 
> run the frames one after the other. If I run my 3ghz machine to render 
> the sequence my four other nodes will still render far quicker than the 
> single machine.

Yes, but you have 4 cores in the one box, so its semantically the same
as 4 CPU cluster, but its all on one board. Whats more, the interconnect
between each one is hypertransport, not ethernet, this speeds things up
a little there. Not to mention the faster bus speeds for memory and the
like.

> There are few jobs a cluster is better at than a single machine and this 
> is one of them.

Oh, I agree completely, this is why even with 5000 Node Beowulf clusters
and the like, sun are still shipping 108 CPU boxen. 

> Well the plans I have is to fit the raw motherboards one on top of the 
> other with just bars spacing each board. A basic box around with vents 
> and a single fan to draw air. All passively cooled so no need for much 
> cooling. There is something like the one I want to build on the 
> www.mini-itx.com projects page.

I have considered this setup in the past, and played with it, and found
that it reaches a point where you just get a 1U server, or 10 and stick
them in a rack.

What sort of size dataset, and what tools are you using? I may have a
weeks spare CPU time on a quad core opteron box during the next month
and would be interested in benchmarking this.

Thoughts?

J
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (GNU/Linux)

iD8DBQFFvnLa42M0lILkmGIRAtU7AJ9H8RzgvNNgavFK0IHuXQxKg87OUgCgzf0a
t8GUd721YzXpR89vT5x4miA=
=jreO
-----END PGP SIGNATURE-----