Local and Global Cache Miss rate


#1

Suppose that in 1000 memory references 50 misses in L1 cache, 30 misses in L2 cache. The miss penalty for L2 cache to memory is 200 clock cycles. The hit time for L2 cache and L1 cache are 5 clock cycles and 1 clock cycle respectively. What is the local miss rate for L2 cache and Global miss rate of L1 cache ?

A. 50%, 0.05
B. 60%, 0.03
C. 60%, 0.05
D. 50%, 0.02


#2

Local Miss rate of L2 cache = (misses in L2 cache) / (misses in L1 cache) = 30/50 = 0.6 (60%)

Global Miss rate of L1 cache = (misses in L1 cache) / (Total memory references) = 50/1000 = 0.05

So option C is correct.

Additional points to Note:
Global Miss rate of L1 cache = Local Miss rate of L1 cache

Global Miss rate of L2 cache = (misses in L2 cache) / (Total memory references) = 30/1000 = 0.03