[Beowulf] New HPCC results, and an MX question

Greg Lindahl lindahl at pathscale.com
Tue Jul 19 20:53:41 PDT 2005

On Tue, Jul 19, 2005 at 11:11:33PM -0400, Patrick Geoffray wrote:

> If you randomize the machine list, then there is no difference
> between the random ring latency and the average pingpong.


There likely will be a difference, because average pingpong doesn't
run on all the cpus. On a 4-cpu node, that can make a big difference.

To give you an example, look at the Quadrics reported numbers for
random ring latency of 11.4568 usec and average ping-pong of 1.552
usec. This is on a 2-cpu node (I think). I'd bet that most of this
difference has nothing to do with machine size. But I'd be happy to be
proven wrong.

Hopefully someone will publish a Myrinet MX-based set of HPCC results
soon. (hint, hint!)

> >As I said, it is in the process of being published, and I attached
> >the relevant info to my posting.
> I know, tongue-in-cheek. Will you publish the raw numbers on the web 
> site eventually ?

Yes. That's what I meant in the first place.

-- greg

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