Re: [理工] 階層式記憶體
※ 引述《celiao (還沒想到暱稱....)》之銘言：
: 張凡書裡的練習題 :
: Media applications that play audio or video files are part of a class
: of workloads called "streaming" workloads; i.e., they bring in large
: amounts of data but do not reuse much of it. Consider a video streaming
: workload that accesses a 512 KB working set sequentially with the following
: address stream:
: 0, 4, 8, 12, 16, 20, 24, 28, 32,...
: (1)Assume a 64 KB direct-mapped cache with a 32-byte line.What is the miss
: rate for the address stream above. How would you categorize the misses
: this workload is experiencing, based on the 3C model.
: (2)Recompute the miss rate when the cache line size is 16 bytes, 64 bytes,
: and 128 bytes?What kind of locality is this workload exploiting?
: 解答是: (1)12.5% miss rate.
: The miss rate doesn't change with cache size or working set.
: These are cold misses.
: (2)25%, 6.25% and 3.125% miss rates for 16-byte, 64-byte and 128-byte
: blocks.
: Spatial locality.
這題跟64KB direct-mapped cache應該沒關係
因為只要容的下 一個BLOCK就夠了
每次都只有用一個block直到work load變了才會換
(不會一直換block) 先看下面就大概會懂0.0
第一題
題目沒講通常都是byte address
一個block 是32-byte
所以0,4,8,12,16,20,24,28,32
除32取下限 1後面還有七個1總共八個
轉成block address為 0 0 0 0 0 0 0 0 1
這裡第一個有cold miss
所以每八個 會有一次cold miss
把一個block載上來
miss rate為1/8=12.5%
第二題
16byte也是
0 .4,8,12 block address都0
第一個會發生cold miss
1/4=25%
剩下兩個自己做看看吧
應該是這樣沒錯
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※ 編輯: hunter0904 來自: 122.126.122.61 (10/29 08:31)
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