A 3D example of KSPSolve?

[Shi Jin]

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




 
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