This example is the most dramatic when These conditions are met by the native SGI shared memory implementation, whose implementation changes to Rendevous for messages longer than 64 bytes, and which pulls the data with a memcpy. Note that this choice is good for pairwise communication, because it limits the amount of data coping and leaves the data in the cache of the recipient. The tradeoff is the synchronization delays shown in this example.

This example suggests that for systems like the SGI that switch to rendezvous at small message sizes and that pull data, it is better to post MPI_Isends before MPI_Irecvs. This is the opposite of the case where aggressive eager delivery is used.