The leave pinned will not help in this context. It can only help for devices capable of real RMA operations and that require pinned memory, which unfortunately is not the case for TCP. What is [really] strange about your results is that you get a 4 times better bandwidth over TCP than over shared memory. Over TCP there are 2 extra memory copies (compared with sm) plus a bunch of syscalls, so there is absolutely no reason to get better performance.

The Open MPI version is something you compiled or it came installed with the OS? If you compiled it can you please provide us the configure line?

  Thanks,
    george.

On Jul 29, 2009, at 13:55 , Dorian Krause wrote:

Hi,

--mca mpi_leave_pinned 1

might help. Take a look at the FAQ for various tuning parameters.


Michael Di Domenico wrote:
I'm not sure I understand what's actually happened here.  I'm running
IMB on an HP superdome, just comparing the PingPong benchmark

HP-MPI v2.3
Max ~ 700-800MB/sec

OpenMPI v1.3
-mca btl self,sm - Max ~ 125-150MB/sec
-mca btl self,tcp - Max ~ 500-550MB/sec

Is this behavior expected?  Are there any tunables to get the OpenMPI
sockets up near HP-MPI?
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