[問題] page fault
想確認一下..是不是我搞錯了..
題目是:
A computer whose processes have 1024 pages in their address
spaces keeps its page tables in memory. The overhead required for
reading a word from the page table is 500 nsec. In order to reduce
the overhead, the computer has a TLB,which holds 32(virtual page,
physical page frame) pairs, and can do a look up in 100 nsec.
What hit rate is needed to reduce the mean overhead to 200 nesec?
書上寫: 假設TLB的hit rate 為h，則:
100ns+(1-h)*500ns=200ns
h=80%
我的問題是，那為什麼100ns不需要乘上h呢?
謝謝幫忙
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