CPU Scheduling Overview

CPU scheduling decides the order in which jobs run on a system's processor. Different strategies impact efficiency and overall system performance.

Assumptions in Our Analysis

To keep things simple, we assume:

• Every job takes the same amount of time to complete.
• All jobs arrive together, so there's no waiting for new arrivals.
• Once a job starts, it runs straight to the end without being paused.
• Jobs use only the CPU—there's no interaction with I/O devices.
• The runtime for each job is known in advance.

Measuring Performance: Two Key Metrics

To compare scheduling methods, we use two key metrics:

1. Turnaround Time (Tᵀ)

Turnaround time tells us how long a job spends in the system from arrival to completion:

Turnaround Time = Completion Time - Arrival Time

A lower turnaround time means jobs finish sooner, which is good for overall system efficiency.

2. Response Time (Tᴿ)

Response time measures how long a job waits before it starts running for the first time: