30 Jan
2008
30 Jan
'08
3:47 p.m.
So the latency will increase by 4 times, but why will the messaging rate decrease? -- Pavan On 01/30/2008 03:45 PM, Rajeev Thakur wrote:
Hmm.. You lost me. Are you saying that the multi-threaded case with 4 threads has more than 4X communication as compared to the single threaded case?
Each thread calls Isend-Irecv 160,000 times. With 4 threads, there will be 640,000 calls. There is a barrier across the entire set. But there is no division by 4 in the time calculation.
Rajeev
-- Pavan Balaji http://www.mcs.anl.gov/~balaji