Yes. The results follow. --- Satish Balay <balay at mcs.anl.gov> wrote:
> Can you send the optupt from the following runs. You > can do this with > src/ksp/ksp/examples/tutorials/ex2.c - to keep > things simple. > > petscmpirun -n 2 taskset -c 0,2 ./ex2 -log_summary | > egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 1.81198e-06 Average time for zero size MPI_Send(): 5.00679e-06 > petscmpirun -n 2 taskset -c 0,4 ./ex2 -log_summary | > egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 2.00272e-06 Average time for zero size MPI_Send(): 4.05312e-06 > petscmpirun -n 2 taskset -c 0,6 ./ex2 -log_summary | > egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 1.7643e-06 Average time for zero size MPI_Send(): 4.05312e-06 > petscmpirun -n 2 taskset -c 0,8 ./ex2 -log_summary | > egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 2.00272e-06 Average time for zero size MPI_Send(): 4.05312e-06 > petscmpirun -n 2 taskset -c 0,12 ./ex2 -log_summary > | egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 1.57356e-06 Average time for zero size MPI_Send(): 5.48363e-06 > petscmpirun -n 2 taskset -c 0,14 ./ex2 -log_summary > | egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 2.00272e-06 Average time for zero size MPI_Send(): 4.52995e-06 I also did petscmpirun -n 2 taskset -c 0,10 ./ex2 -log_summary | egrep \(MPI_Send\|MPI_Barrier\) Average time for MPI_Barrier(): 5.00679e-06 Average time for zero size MPI_Send(): 3.93391e-06 The results are not so different from each other. Also please note, the timing is not exact, some times I got O(1e-5) timings for all cases. I assume these numbers are pretty good, right? Does it indicate that the MPI communication on a SMP machine is very fast? I will do a similar test on a cluster and report it back to the list. Shi ____________________________________________________________________________________ Need Mail bonding? Go to the Yahoo! Mail Q&A for great tips from Yahoo! Answers users. http://answers.yahoo.com/dir/?link=list&sid=396546091
