[petsc-users] scaling problem

[Barry Smith]

   Aron,

     Please send to petsc-maint at mcs.anl.gov (to save petsc-user bandwidth) the -log_summary for 1 node 1 core, 1 node 2 core, 1 node 4 core, 1 node 8 core, 2 node, 1 core per node, 4 node 1 core per node, 8 core 1 core per node, 10 node, 1 core per node.

   Barry

On May 26, 2012, at 5:13 PM, Aron Roland wrote:

> Dear All,
> 
> I have some question on some recent implementation of PETSc for solving a large linear system from a 4d problem on hybrid unstructured meshes. 
> 
> The point is that we have implemented all the mappings and the solution is fine, the number of iterations too. The results are robust with respect to the amount of CPU used but we have a scaling issue. 
> 
> The system is an intel cluster of the latest generation on Infiniband.
> 
> We have attached the summary ... with hooefully a lot of informations. 
> 
> Any comments, suggestions, ideas are very welcome. 
> 
> We have been reading the threads with that are dealing with multi-core and the bus-limitation stuff, so we are aware of this. 
> 
> I am thinking now on an open/mpi hybrid stuff but I am not quite happy with the bus-limitation explanation, most of the systems are multicore. 
> 
> I hope the limitation are not the sparse matrix mapping that we are using ... 
> 
> Thanks in advance ...
> 
> Cheers
> 
> Aron 
> 
> 
> 
> 
> 
> <benchmark.txt>