A computer with a 5 stage pipeline is measured and has the f

A computer with a 5 stage pipeline is measured and has the following characteristics Instruction Type % of instructions. Avg. stall cycles/instructions Branches .3 .7 Loads&Stores; .2 .2 ALU ops .4 0 Other .1 .2 what is the average CPI for the computer? What is the speedup (compared to an unpipelined machine) for this machine?

Solution

Answer:

1)What is the average cpi for the computer?

instruction type % of instruction avg,stall cycle/instruction

branches .3 .7

loads& store .2 .2

ALU OPS .4 .0

OTHERS .1 .2

Result:

CPI=(.3*.7+.2*.2+.4*.0+.1*.2)=0.27

2) what is speedup for this machine?

If you want calculate speedup your machine follow the below equation

We can also measure speedup in instructions per cycle (IPC), which is a throughput and the inverse of CPI. Using the speedup formula gives.

Speedup = IPC/CPI

Here IPC=1.1, CPI=0.27

Speedup = IPC/CPI = 1.1/0.27 = 4.07

speedup = n = performent A/performence B = Execution Time B/Execution Time A