CPU scheduling

Question

Assume that a process has CPU burst time for last three runs as 4, 5 and 4 (last). Given that last predict burst time was 5 and α = 0.8. The next predict of CPU burst time for process when CPU scheduler is shortest process next with exponential averaging is _________. in sec (upto 1 to decimal places).

Answer 1

T_n+1 = αt_n+ (1−α) T_n

where T_n+1 is the predicted value of the next CPU burst time.

0 ≤ α ≤ 1

 T_n is the predicted value of the last CPU burst (here T_n = 5s),

t_n is the (actual) last run time of the process (here t_n is 4s) and  α = 0.8

Putting in all values,

T₄  =   0.8 * 4 + (1 - 0.8)*5 = 3.2 + 1 = 4.2 sec.

So, the next predict of CPU burst time for process is 4.2 sec.

Comments

@ank73811

can you provide some resources to read this

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https://www.geeksforgeeks.org/operating-system-shortest-job-first-scheduling-predicted-burst-time/