Question

List three criteria used to compare scheduling algorithms.

Answer 1

Answer:

CPU Utilization

We want to keep the CPU as busy as possible. It may range from 0 to 100%. In real time system, it suits range from 40% (for a lightly loaded system ) to 90% ( for heavily loaded system ).

Throughput

If the CPU is busy executing processes, then work is being done. One measure of work is the number of processes completed per time unit for throughput. For time processes, these may be a one process for one minute. For shorter transactions, throughput might be 10 processes per minute.

Turnaround Time

From the submission time of a process to its completion time is turnaround time. It is the sum of total time period spends waiting to get into memory, waiting in the ready queue, executing in the CPU and doing input/output operations.

Explanation:

Answer 2

Explanation:

* There are several different criteria to consider when trying to select the "best" scheduling algorithm for a particular situation and environment, including:

• CPU utilization : - Ideally the CPU would be busy 100% of the time, so as to waste 0 CPU cycles. On a real system CPU usage should range from 40% ( lightly loaded ) to 90% ( heavily loaded. )

• Throughput : - Number of processes completed per unit time. May range from 10 / second to 1 / hour depending on the specific processes.

• Turnaround time : - Time required for a particular process to complete, from submission time to completion. ( Wall clock time. )

• Waiting time : - How much time processes spend in the ready queue waiting their turn to get on the CPU.

( Load average - The average number of processes sitting in the ready queue waiting their turn to get into the CPU. Reported in 1-minute, 5-minute, and 15-minute averages by "uptime" and "who". )

• Response time : - The time taken in an interactive program from the issuance of a command to the commence of a response to that command.

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