[petsc-users] performance of hmpi

[George Pau]

Hi,

I am comparing between

mpiexec -n 2 myexec -pc_type bjacobi -ksp_type preonly

and

mpiexec -n 1 myexec -pc_type hmpi -ksp_type preonly -hmpi_pc_type bjacobi
-hmpi_ksp_type preonly -hmpi_spawn_size 2

My matrix size is 10500x10500 and it is a non-symmetric and not necessarily
positive definite all the time.    I am not seeing any improvement in
performance in hmpi case going from 1 process to 2 processes (in fact there
is a slight increase).  With the bjacobi I do see some improvement.  Is
this expected due to perhaps communication costs?  Under what situation
will hmpi be useful?  Should I be using hmpi only on much larger problems
and with more processes?

Thanks,
George

-- 
George Pau
Earth Sciences Division
Lawrence Berkeley National Laboratory
One Cyclotron, MS 74-120
Berkeley, CA 94720

(510) 486-7196
gpau at lbl.gov
http://esd.lbl.gov/about/staff/georgepau/
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