[mpich-discuss] CPU usage versus Nodes, Threads

[Qiguo Jing]

Hi Bob,

Thanks for your suggestions.   Here are more tests.  We actually have three clusters.

Cluster 1 and 2:  8 nodes, (2 Processors, 4 cores/processor, no HT – Total 8 Threads)/node
Cluster 3:              8 nodes, (1 Processors, 4 cores /processor, HT – Total 8 Threads )/node

We also have a standalone machine:  2 processors, 6 cores/processor, HT – total 24 threads.


For one particular case:

Cluster 1 and 2 take 48 min to finish with 8 nodes, 8 threads/node,  60% CPU usage;  53 min to finish with 3 nodes, 8 threads/node, 90% CPU usage;

Cluster 3 takes 227 min to finish with 8 nodes, 8 threads/node, 20% CPU usage; 207 min to finish with 3 nodes, 8 threads/node, 50% CPU usage;

Standalone machine takes 82 min to finish with 24 threads, 100% CPU usage.

It looks like with 24 threads, they should be pretty busy?   Could the above phenomena be a hardware issue more than software?

Qiguo

From: Bob Ilgner [mailto:bobilgner at gmail.com]
Sent: Thursday, October 23, 2014 1:11 AM
To: discuss at mpich.org<mailto:discuss at mpich.org>
Subject: Re: [mpich-discuss] CPU usage versus Nodes, Threads

Hi Qiguo,