1. [15 marks] Amdahl's Law.

 

On a uniprocessor, perfectly serial portion A of program P1 consumes 15 s,

while perfectly parallel portion B consumes 95 s.  The theoretical maximum

speedup for P1 is obtained by using an infinite number of processors.

 

a) [5 marks] What integral number of processors is required to achieve at

least half the theoretical maximum speedup for P1?

                                                       ans: ____ processors

 

b) [5 marks] Perfectly serial portion A of larger program P2 consumes 15 s,

while perfectly parallel portion B consumes 950 s.  What integral number of

processors is required to achieve, for P2, at least the theoretical maximum

speedup for P1?

                                                       ans: ____ processors

 

c) [5 marks] Perfectly serial portion A of even larger program P3 consumes

15 s, while perfectly parallel portion B consumes 9,500 s.  What integral

number of processors is required to achieve, for P3, at least the

theoretical maximum speedup for P1?

                                                       ans: ____ processors