High Performance Computing 1
Amdahl’s Law
•Consider the execution of a program on p processors - let the part q (0<q<1) of each operation be parallelized. Maximum speedup
–spfalse = tk/tp  = k/ [(q/p) +(1-q)]
–Indicates the rapid loss of speedup if parallel fraction is not high enough as p increases
–To get 50% efficiency i.e. 256 on 512 q =0.998