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Alternative Implementation
•Message passing is “heavy weight”
because it needs send, acknowledgement, marshalling
•Using
one-sided communication is easy
my_temp := data1; -- store where neighbor can get it
post(P-1,my_data_ready); -- say that it’s available
much computing; -- overlap
wait(P+1,his_data_ready);
-- wait if neighbor not ready
get(P+1.his_temp, loc1); --
get it now
•One-sided
comm is more efficient because of reduced waiting and less network traffic Most computers do not implement shmem