Topic: virtual memory.

Question

Suppose the average page fault service time is 20 milliseconds and memory access time is 200 nanoseconds. Assuming we wish to have less than 10% degradation in memory access when a page fault occurs estimate the value  of the fault rate must be less than.

Comments

@gidoranking,less than what?Your question is seemingly incomplete.

Answer 1

Memory access time = 200 nsec

page-fault service time = 20 msec

EAT = (1 – p)  ×  200 + p (20  × 10^6) =

performance degradation < 10 %

without page fault access time= 200 nsec & with page fault=220 nsec

220=200 - 200p + 20,000,000p

p= 20/19999800 => p=0.000001