Consider a computer system where the overhead required for reading a word from t

Question

Consider a computer system where the overhead required for reading a word from the page table is 1.25ms. A TLB lookup of a word requires 250 ns.

1.     What would be the mean access time for reading a word from a virtual address if the TLB hit rate was 100%?

2.     What would be the mean access time for reading a word from a virtual address if the TLB miss rate was 90%? Show your work for partial credit.

3.     What hit rate is needed to reduce the mean access time for reading a word from a virtual address to 500 ns? Show your work for partial credit.

Explanation / Answer

1. mean access time= 250ns

2. mean access time =0.9*250 +0.1*1.25*10^3 ns =350ns

3. let hit rate =x

x*250+(1-x)*1250 = 500

1250-1000x=500

750 =1000x

x=0.75

hence hit rate is 75%

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.