A demand paging system with page table held in registers, takes 5 ms to service a page fault, if empty page is available or if the page is to replaced is not dirty. It takes 15 ms if the replaced page is dirty. Memory access time is 1 ms. Assume we want an effective access time 2 ms and that the page to be replaced is dirty 60% of the time. What is the approximate page fault rate to meet this access time requirement?
A demand paging system with page table held in registers, takes 5 ms to service a page fault, if empty page is available or if the page is to replaced is not dirty. It takes 15 ms if the replaced page is dirty. Memory access time is 1 ms. Assume we want an effective access time 2 ms and that the page to be replaced is dirty 60% of the time. What is the approximate page fault rate to meet this access time requirement?
The correct option is C 0.01%
A demand paging system with page table
held in registers takes 5 ms to service a page fault, if empty page is
available or if the page is to replaced is not dirty. It takes 15 ms if the
replaced page is dirty. Memory access time is 1ms. Assume we want an effective
access time 2 ms and that the page to be replaced is dirty 60% of the time. The
approximate page fault rate to meet this access time requirement is 0.01%.
Let hit ratio for main
memory = p.
Then desired time = p x main memory access time +
(1 - p) page fault time
2 = p x 1 + (1 - p) (.6 x 15 + .4 x 5)10^3
2 = p + (1 - p) (9 + 2) 10^3
p = (1/(11 x 10^3)) = 0.01%.
Paging is a memory management scheme by
which a computer stores and retrieves data from secondary storage for use in
main memory. In this scheme, the operating system retrieves data from secondary
storage in same-size blocks called pages.
A demand paging system with page table held in registers takes 5 ms to service a page fault, if empty page is available or if the page is to replaced is not dirty. It takes 15 ms if the replaced page is dirty. Memory access time is 1ms. Assume we want an effective access time 2 ms and that the page to be replaced is dirty 60% of the time. The approximate page fault rate to meet this access time requirement is 0.01%.
Let hit ratio for main
memory = p.
Then desired time = p x main memory access time +
(1 - p) page fault time
2 = p x 1 + (1 - p) (.6 x 15 + .4 x 5)10^3
2 = p + (1 - p) (9 + 2) 10^3
p = (1/(11 x 10^3)) = 0.01%.
Paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages.
