A 3D example of KSPSolve?

[Shi Jin]

Furthermore, I did a multi-process test on the SMP.
petscmpirun -n 3 taskset -c 0,2,4 ./ex2 -ksp_type cg
-log_summary | egrep \(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 4.19617e-06
Average time for zero size MPI_Send(): 3.65575e-06

 petscmpirun -n 4 taskset -c 0,2,4,6 ./ex2 -ksp_type
cg -log_summary | egrep \(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 1.75953e-05
Average time for zero size MPI_Send(): 2.44975e-05

 petscmpirun -n 5 taskset -c 0,2,4,6,8 ./ex2 -ksp_type
cg -log_summary | egrep \(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 4.22001e-05
Average time for zero size MPI_Send(): 2.54154e-05

petscmpirun -n 6 taskset -c 0,2,4,6,8,10 ./ex2
-ksp_type cg -log_summary | egrep
\(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 4.87804e-05
Average time for zero size MPI_Send(): 1.83185e-05

petscmpirun -n 7 taskset -c 0,2,4,6,8,10,12 ./ex2
-ksp_type cg -log_summary | egrep
\(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 2.37942e-05
Average time for zero size MPI_Send(): 5.00679e-06

petscmpirun -n 8 taskset -c 0,2,4,6,8,10,12,14 ./ex2
-ksp_type cg -log_summary | egrep
\(MPI_Send\|MPI_Barrier\)
Average time for MPI_Barrier(): 1.35899e-05
Average time for zero size MPI_Send(): 6.73532e-06

They all seem quite fast.
Shi

--- Shi Jin <jinzishuai at yahoo.com> wrote:

> 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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