[petsc-users] testing scalability for ksp/ex22.c
Francis Poulin
fpoulin at uwaterloo.ca
Thu Feb 23 14:16:16 CST 2012
Hello,
I am learning to use PetSc but am just a notice. I have a rather basic question to ask and couldn't not find it on the achieves.
I am wanting to test the scalability of a Multigrid solver to the 3D Poisson equation. I found ksp/ex22.c that seems to solve the problem that I'm interested in. I ran it on a large server using different processors.
The syntax that I use to run using MPI was
./ex22 -da_grid_x 64 -da_grid_y 64 -da_grid_z 32
I tested it using 2, 4, 8, 16 cpus and found that the time increases. See below. Clearly there is something that I don't understand since the time should be reduced.
n wtime
---------------------
2 3m58s
4 3m54s
8 5m51s
16 7m23s
Any advice would be greatly appreciated.
Best regrads,
Francis
More information about the petsc-users
mailing list