Performance improvement of parallel processing systems with fully or highly connected optical interconnections over systems with a bus

We analyzed the performance improvement of parallel processing systems with fully or highly connected optical interconnections over systems with a bus. Solving an 1024 by 1024 point 2-D FFT with 300Mflops processors and 66MHz interconnections, the speedup factor of the execution time of fully interconnected systems over systems with a bus is 3.1 for 32 PEs, and 1.2 for 4 PEs. We proposed an extended ring system as a highly connected interconnection, and also discussed the speed-up factor as for highly connected interconnections.