PERFORMANCE EVALUATION AND MODELING OF COLLECTIVE COMMUNICATIONS ON CRAY-T3D

We present in this paper the results of various communication benchmar ks on a Gray T3D MPP system. They are composed of most-used communicat ion schemes in parallel applications and numerical kernels. They have been implemented using PVM message-passing libraries on the Gray T3D s ystem. For each of these benchmarks, we propose a model depending on t he size of the message communicated and the number of processors invol ved. We verify that the error between the proposed model and the measu res is very small (0.8% in average for point-to-point communications a nd 3% in average for collective communications).