Basic HTML version of Foils prepared February 13 00
| Consider N grid points in P processors with grain size n = N2/P |
| Sequential Time T1 = 4N2 tfloat |
| Parallel Time TP = 4 n tfloat + 4 ?n tcomm |
| Speed up S = P (1 - 2/N)2 / (1 + tcomm/(?n tfloat) ) |
| Both overheads decrease like 1/?n as n increases |
| This ignores communication latency but is otherwise accurate |
| Speed up is reduced from P by both overheads |
| Load Imbalance Communication Overhead |