why cant I use 100% cpu usage in parallel programs

BehdadKm · 09-06-2014, 06:21 AM

Im testing a program in Geant4(a toolkit on basis on c++)on a cluster,which is running linux CentOS 6.5,and it has 3 Intel(R)4770k processors,total 12 cores(24 CPU).
The issue is that when I run the program on the cluster, only the cpu usage of the master node is shown as 100%, and the other two nodes are almost unsed.
I also tested another program,all of 24 totally are used(100% cpu).

Thanks in advance!

btmiller · 09-06-2014, 12:50 PM

Have you checked to make sure that the program is actually running on all 3 nodes on the cluster? If it is, perhaps it is highly dependent on communication bandwidth and latency, meaning that if your network is too slow, you won't be able to effectively take advantage of all the processors.

BehdadKm · 09-07-2014, 02:50 AM

Quote:

Originally Posted by btmiller

Have you checked to make sure that the program is actually running on all 3 nodes on the cluster? If it is, perhaps it is highly dependent on communication bandwidth and latency, meaning that if your network is too slow, you won't be able to effectively take advantage of all the processors.

Thank you for your attention and reply.