[理工] [計組] EAT類題目的機率敘述問題
做補習班講議整理的習題中，對於計算EAT(Effective Access Time)時
機率的取法有些疑問。以下兩題分別為台大交大題目。
(只寫出部份題目)
1.Let the hit ratio of TLB and the page fault rate be 98% and 0.0001%
respectively.
解答的計算為：
TLB hit: 98%
TLB miss後從page table找，table miss: 2%*0.0001%
TLB miss後從page table找，table hit: 2%*0.9999%
2.(Two-level cache design)
Suppose the miss rate per instruction at the primary cache is 5%.
How much faster will the machine be if we add a secondary cache that has
a 20ns access time for either a hit or a miss and is large enough to
reduce the miss rate to main memory to 2%.
解答的計算為：
Primary cache hit: 95%
Primary cache miss，在secondary cache找到: 5%-2% = 3%
Primary cache miss，secondary cache miss，從memory載入: 2%
在計算方面沒問題，但是以上兩題的題目敘述看不太出來他所表達的機率是指
"全部機率"或是"部份機率中的機率"
請問各位怎麼解？ 謝謝
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