Correct Answer - Option 3 : 0.7 ns
Data:
Cache
Cache = T1 = 0.6 ns
Hit ratio = H1 = p = 0.98
Miss ratio = 1 – p = 1 – 0.98 = 0.02
Cache = T2 = 3 ns
Hit ratio = H2 = q = 0.95
Miss ratio = 1 – q = 1 – 0.95 = 0.05
Main memory
Main memory = T3 = 50 ns
Hit ratio = 100% = 1 (assume since nothing is given)
Formula:
Tavg = T1 + (1 – p)T2 + (1 – p)(1 – q)T3
Calculation:
Tavg = 0.06 + (0.02) × 3 + ((0.02) × (0.05) × 50
Tavg = 0.662 ≈ 0.7 ns
Important Point:
Serial addition of chip is taken