two things:
1. Too many mpi processes on one node leading to processes pre-empting each other
2. Contention in your network.

On Wed, Feb 29, 2012 at 8:01 AM, Pinero, Pedro_jose <Pedro_jose.Pinero@atmel.com> wrote:

Hi,

 

I am using OMPI v.1.5.5 to communicate 200 Processes in a 2-Computers cluster connected though Ethernet, obtaining a very poor performance. I have measured each operation time and I haver realised that the MPI_Gather operation takes about 1 second in each synchronization (only an integer is send in each case). Is this time range normal or I have a synchronization problem?  Is there any way to improve this performance?

 

Thank you for your help in advance

 

Pedro


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