Consider three branch prediction schemes: predict not taken, predict taken, and dynamic prediction. Assume that they all have zero penalties when they predict correctly and two cycles when they are wrong. Assume that the average predict accuracy of the dynamic predictor is 90%. Which predictor is the best choice for the following branches? [1.5 pts]a. A branch that is taken with 5% frequencyb. A branch that is taken with 70% frequencyc. A branch that is taken with 95% frequency

Question

Engineering

Captain

4 April, 13:28

Consider three branch prediction schemes: predict not taken, predict taken, and dynamic prediction. Assume that they all have zero penalties when they predict correctly and two cycles when they are wrong. Assume that the average predict accuracy of the dynamic predictor is 90%. Which predictor is the best choice for the following branches? [1.5 pts]a. A branch that is taken with 5% frequencyb. A branch that is taken with 70% frequencyc. A branch that is taken with 95% frequency

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Answers (1)

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Greta Chang · Answer 1

Check the explanation

Explanation:

1. When a branch is taken with 5% frequency, the branch prediction scheme is "predict taken" because the process has to begin fetching and then execute at the target address.

2. When a branch is taken with 95% frequency, the branch prediction scheme is "predict not taken" because the branch outcome is definitely known.

3. When a branch is taken with 70% frequency, the prediction scheme is "dynamic prediction" the branch prediction can dynamically change during the program execution.