Recently I installed OpenMPI 1.4.3 on my cluster. I found that SYSTEM CPU is higher than older versions of 1.4.X, when I ran our FEM program. Further more, OMPI_1.4.3 is a little bit slower than 1.4.2. What is the differnece between these two versions, or what affects the "SYSTEM CPU" and execution speed?
USER CPU SYSTEM CPU OpenMPI 1.4.2 99% 1% OpenMPI 1.4.3 95% 5% Information of my cluster is as follows: Nodes: 8 nodes Cores of a node: 8 cores (AMD Opteron) Network: DDR Infiniband OS: CentOS 5.3 Compiler: PGI 10.5 with ACML 4.3 Typical command line: mpirun -host n1,n2,n3,n4 -np 8 -x OMP_NUM_THREADS=4 ./Solver Best regards, tmishima