The quick answers are yes and nothing. Open MPI seamlessly support
shared memory communications when we detect that 2 processes are on
the same node. In fact Open MPI can use different communication
methods (read networks) between the processes of the same application.
Please read our FAQ f
Hi,
Thanks for the reply,
A few Additional questions,
1. Does OpenMPI has the optimisations required to ensure that when send/recv
is called between 2 ranks on the same node, the shared memory kind of
methods should be used?
2. If a programmer wants to implement such a logic(optimisations for l
On Tue, Nov 07, 2006 at 05:02:54PM +, Miguel Figueiredo Mascarenhas Sousa
Filipe wrote:
> if your aplication is on one given node, sharing data is better than
> copying data.
Unless sharing data repeatedly leads you to false sharing and a loss
in performance.
> the MPI model assumes you don
Hi,
On 11/7/06, Chevchenkovic Chevchenkovic wrote:
Hi,
I had the following setup:
Rank 0 process on node 1 wants to send an array of particular size to Rank
1 process on same node.
1. What are the optimisations that can be done/invoked while running mpirun
to perform this memory to memory tr
Chev
Interesting question; I too would like to hear about it from the experts in
this forum. However, off the top of my head, I have the following advise for
you.
Yes, you could share the memory between processes using the shm_xxx system
calls of unix. However, it would be a lot easier if you us
Hi Herve
Sorry you are experiencing these problems. Part of the problem is that I
have no access to a BJS machine. I suspect the issue you are encountering is
that our interface to BJS may not be correct - the person that wrote it, I
believe, may have used the wrong environmental variables. At lea
Hi Ralf, sorry for the delay in the answer but I encountered some difficulties
to access to internet since yesterday.
I have tried all your suggestions but I continue to experience problems.
Actually, I have a problem with bjs on the one hand that I may submit to a
bproc forum and I still spawn
Hi,
I had the following setup:
Rank 0 process on node 1 wants to send an array of particular size to Rank
1 process on same node.
1. What are the optimisations that can be done/invoked while running mpirun
to perform this memory to memory transfer efficiently?
2. Is there any performance gain if
