[MPICH] Can I ask MPI to not copy the data to shared-mem ?

[Darius Buntinas]

Well, you specify one buffer in the call to MPI_Send and another buffer 
in MPI_Recv, so there would have to be at least one copy.  You can't do 
it without any copies (otherwise, how would the data get from the send 
buffer to the receive buffer?).

MPICH2 does support communication over shared memory (as opposed to over 
a network) which improves performance for intranode communication. 
Configure with --with-device=ch3:ssm or --with-device=ch3:nemesis.

Darius


On 10/08/2007 12:22 PM, chong tan wrote:
> If I the pointer passed to MPI_Send and MPI_Recieve are already shared 
> memory, and need not be copied at all ?
>  
> If so, How ? 
>  
> thanks
> tan
>  
> 
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