作者bin272max (Ellison)
看板Grad-ProbAsk
標題[理工] OS effective M.A. time
時間Mon Jan 14 15:44:04 2013
In a paging system with two-level page tables,
hit ratio is 80%
search the TLB need 10 ns
memory access need 100ns
what is the effective memory access time?
解答:
0.8*(10+100)+0.2*(10+300) =150ns
我想問的是,在300是怎麼來的@@?
TLB的effective ma time公式中
失敗的存取時間不是應該為
TLB access time+2*ma time?
先感謝撥冗解答: )
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推 Frondage:two-level查page table就要花兩次memory access的時間 01/14 15:48
推 BuliBuchi:TLB在2-level就查兩次了~ 之後再去實體位址存 共三次 01/14 15:49
→ bin272max:懂了!感謝 : ) 01/14 15:51