Below is the precedence graph for a set of tasks to be executed on a parallel…
2011
Below is the precedence graph for a set of tasks to be executed on a parallel processing system S.
What is the efficiency of this precedence graph on S if each of the tasks T1, T2, T3,....T8 takes the same time and the system S has five processors?
- A.
25%
- B.
40%
- C.
50%
- D.
90%
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Show answer & explanation
Correct answer: B
Efficiency is calculated as Total Work divided by (Number of Processors × Parallel Execution Time). Here, Total Work is 8 task units. Number of Processors is 5. Parallel Execution Time corresponds to the critical path length in the precedence graph. Efficiency = 8 / (5 × Critical Path Length).