Question 4 (10 points) In this problem, we are going to study how adding increasing number of cores in a system in a practical system modifies its speedup. Assume a single core has the following CPIs for each class of instructions: 1. Load/Store(L/S)= 12 2. Arithmetic= 1 3. Branch=5 Each core runs on a 2GHz clock frequency Also assume that we are executing a program in our system comprising the following number of instructions: 1. Load/Store(L/S) = 1.28E9 (this is the same as writing 1.28 * 10%) 2. Arithmetic= 2.56E9 3. Branch=2.56E8 Now, assume that, as the program is parallelized to run over multiple cores, the number of arithmetic and load/store instructions per core is divided by 0.7 xp (where p is the number of cores) but the number of branch instructions per processor remains the same. So for example if p=2, we divide the arithmetic and L/S instructions per core by 0.7*2=1.4 each. (Ideally, we would divide the above parallelable instructions just by p; but sometimes in real life, even the same class of instructions cannot be fully parallelized, hence the divide by 0.7 * p instead in this example) A) Find the total execution time for this program on p= 1, 2 and 4 cores, and show the relative speedup of the 2 and 4 cores result relative to the single core result. Accordingly, fill up the values in the table provided below (5pts) cycles ex. time # arith inst. #L/S inst. 2.56E9 1.28E9 #branch inst. 2.56E8 2.56E8 2.56E8 speedup 1 1 2 4 B) If the CPI of ONLY the arithmetic instructions was doubled, what would the impact be on the execution time of the program on p= 1, 2, 4 processors? (2 pts)