作者yesa315 (XD)
看板Grad-ProbAsk
标题[理工] [计组]管线的CPI
时间Mon Oct 19 11:58:12 2009
25% loads, 10% stores,11% branches, 2% jumps, and 52% ALU instructions
For the pipelined design, load take 1 clock cycle when there is no load-use
dependence and 2 when there is.
Branches take 1 when predicted correctly and 2 when not.
Jumps always pay 1 full clock cycle of delay, so their average time is
2 clock cycles. Other instructions take 1 clock cycle.
For pipelined execution, assume that half of the load instructions are
immediately followed by an instruction that uses the result and that
one-quarter of the branches are mispredicted.
Ignore any other hazards.
答案给
Pipelined: Average CPI=1+0.5*1+0.25*1+0.02*1=1.77
好像不太对...
我认为是 CPI=1 + 0.25*1/2*1 + 0.11*1/4*1 + 0.02*1 = 1.11
(load use) (branch) (jump)
有高手可以帮我验证吗?
谢谢
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◆ From: 140.127.208.96
※ 编辑: yesa315 来自: 140.127.208.96 (10/19 11:59)
※ 编辑: yesa315 来自: 140.127.208.96 (10/19 12:00)
1F：推 bennylu:你是对的 10/19 15:26
2F：→ yesa315:3Q 10/19 15:47
3F：推 opcan:请问为何不是1.5*0.25+0.1+0.52+1.25*0.11+2*0.02＝1.1725？ 10/19 22:57