Question

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?

Answer 1

The effective memory access time = 293.5 nanoseconds.

Step-by-step explanation:

Given that:

TLB hit ratio = 90%

= 90/100

= 0.9

Require time to access TLB = 15 nanoseconds &

Time to access main Memory = 85 nanoseconds

The objective is to estimate the effective memory access time in nanoseconds for this system .

The effective memory access time = [TLB Hit ratio ( main memory access time + required time to access TLB) + ( 2 × main memory access time) + required time to access TLB) × (2 - TLB hit ratio)]

The effective memory access time = [0.9 ( 85 + 15 ) + ( 2 × (85 ) + 15) × ( 2 - 0.90)

The effective memory access time = 293.5 nanoseconds.