[Beowulf] MPI Processes + Auto Vectorization

[David N. Lombard]

On Mon, Nov 30, 2009 at 01:24:34PM -0700, amjad ali wrote:
> Hi,
> Suppose we run a parallel MPI code with 64 processes on a cluster, say of 16 nodes. The cluster nodes has multicore CPU say 4 cores on each node.
> 
> Now all the 64 cores on the cluster running a process. Program is SPMD, means all processes has the same workload.
> 
> Now if we had done auto-vectorization while compiling the code (for example with Intel compilers); Will there be any benefit (efficiency/scalability improvement) of having code with the auto-vectorization? Or we will get the same performance as without Auto-vectorization in this example case?
> 
> How can we really get benefit in performance improvement with Auto-Vectorization?

Vectorization takes advantage of the processor's vector instructions to increase data-level parallelism.
How much that benefits your code depends very much on your code; you would need to recompile your code and test.

-- 
David N. Lombard, Intel, Irvine, CA
I do not speak for Intel Corporation; all comments are strictly my own.