Correct Answer - Option 2 : 490 μs
Data:
TLB hit ratio = p = 90% = 0.9
TLB access time = t = 50 μs
Memory access time = m = 400 μs
Effective memory acess time = EMAT
Formula:
EMAT = p × (t + m) + (1 – p) × (t + m + m)
Calculation:
EMAT = 0.9 × (50 + 400) + (1 – 0.9) × (50 + 400 + 400)
EMAT = 490 μs
∴ the overall access time is 490 μs
During TLB hit
Frame number is fetched from the TLB (50 μs)
and page is fetched from physical memory (400 μs)
During TLB miss
TLB no entry matches (50 μs)
Frame number is fetched from the physical memory (400 μs)
and pages are fetched from physical memory (400 μs)
