Assume a system uses 2-level paging and has a TLB hit ratio of 90%. It requires 15 nanoseconds to access the TLB, and 85 nanoseconds to access main memory. What is the effective memory access time in nanoseconds for this system?
A) 22
B) 108.5
C) 30.5
D) 117

Question

Quizplus · Accepted Answer

The effective memory access time (EMAT) is calculated as: EMAT = (TLB hit ratio * (TLB access time + memory access time)) + (TLB miss ratio * (TLB access time + 2 * memory access time)). With a TLB hit ratio of 90% (0.9), TLB access time of 15 ns, and memory access time of 85 ns, the calculation is: EMAT = (0.9 * (15 + 85)) + (0.1 * (15 + 2 * 85)) = 90 + 27 = 117 ns.

Assume a System Uses 2-Level Paging and Has a TLB