[mpich-discuss] MPI polling question with MPI_Iprobe

[Pavan Balaji]

Hi Eric,

On 09/21/2011 01:56 PM, Eric Hui wrote:
> I found that there is MPI_Probe and MPI_Iprobe. It seems like both of
> these functions are doing polling instead of getting notification when
> there is message arrived, so it is taking up 100% of the CPU power even
> when it is just idling to wait for message.

Most MPI implementations are optimized for latency, so they poll 
frequently to ensure that. You can configure MPICH2 with 
--with-device=ch3:sock to get "blocking mode" (meaning MPI will sleep 
when there is nothing to do), but this is very implementation specific. 
If you configure MPICH2 differently or use a different MPI 
implementation, you might go back to the "polling mode" which you are 
currently seeing.

  -- Pavan

-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji