SpeedUP

Question

https://gateoverflow.in/3437/gate2007-it-6-isro2011-25

Why are they not calculating average CPI in pipelined processor and then calculating speedup ???

Comments

speedup= $\frac{np}{p}$

np=time taken by n instructions in a non-piplelined system

p=time taken by n instructions in a piplelined system

Can you show your approach?

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in my context,

speedup = Twp / Tp  {Twp : time without pipelining, Tp : time with pipelining}

Twp = n * 12 clocks,

Tp = there are multiple stages with execution times 3, 2, 5, 4, 6, 2 clocks.

therefore we need to calculate average CPI.

avg CPI = { [m * 1] + [1 * (n - 1)] } / n , [m is number of stages], [n is number of instructions ]

Tp = Avg CPI * T(for 1 clock cycle, which is max time ==> 6 clocks)

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i did a mistake of assuming 'n' no of instructions to be any number since we are taking average, it can be any number.

i didnt read the que nicely, there it is given 'n' as very large....

so that formula for Tp becomes [n * (max time for a stage)].

Now i understood. thnx.