Question

Estimate the average time to access data from memory with the following information, page fault service time = $2$ ms, memory access time = $200$ ns, $10$ page faults for every $10^6$accesses, TLB hit rate = $50\%$, TLB lookup latency = $5$ ns, and a two-level page table for v2p (virtual to physical ) mappings. Assume all page table pages are present in the memory. Page fault service time is the time to execute the page fault handler and update the v2p mapping (via possible evictions of other pages, reading from disk etc.)

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what is ans??

Answer 1

Average access time

                              =Average address translation time+Average memory access time+Average page fault service time

                                    $={{\color{Purple} {Address Translation Time}}}\left \{ {5+2\times 0.5\times 200} \right \}

+{{\color{Red} {Address Memory Access Time}}}2\times 200

+{{\color{Blue} {Avg Page Fault Service Time}}}\frac{10}{10^{6}\times 2\times 10^{6}}$

                               $=625ns$