large clusters and topologies

[Steffen Persvold]

Greg Lindahl wrote:
> 
> > - I suppose Ethernet is not all too efficient with this
> > size, even with switches instead of hubs. What's the largest
> > practical size for an Ethernet 'wulf?
> 
> Depending on the details, Ethernet can work great for larger machines. The
> 1,000 cpu genetic algorithm machine (www.genetic-programming.com) uses
> ethernet, Google's 5,000 cpu cluster uses ethernet, Incyte's 3,000 cpu
> cluster uses ethernet, and so forth. The key is that their application's
> network bandwidth and latency demands aren't maxing out what they have.
> 
> > Any alternatives to Myrinet upwards of that?
> 
> Not really. It depends.
SCI is a great alterative if you need high network bandwidth.
It is also highly scalable.

See http://www.scali.com for more information

> > - Which type of algorithm can take direct advantage of a cube,
> > toroid, ... topology? I would think even a "dumb" job like
> > matrix multiplication might benefit from a 2D lattice (instead
> > of the typical all-to-all unique segment). Comments?
> 
> There are lots of books which discuss this topic. There have been many
> religious wars fought over the subject.
> 
-- 
  Steffen Persvold               Systems Engineer
  Email : mailto:sp at scali.no     Scali AS (http://www.scali.com)
  Tlf   : (+47) 22 62 89 50      Olaf Helsets vei 6
  Fax   : (+47) 22 62 89 51      N-0621 Oslo, Norway