In this project, we implemented all the CPU scheduling algorithms covered during our theory class. The list of CPU scheduling algorithms implemented here are: 1. First-Come, First-Served (FCFS) Scheduling 2. Non-preemptive Shortest-Job-First (SJF) Scheduling 3. Preemptive Shortest-Job-First (SJF) Scheduling 4. Non-preemptive Priority Scheduling 5. Preemptive Priority Scheduling 6. Round Robin (RR) Scheduling 7. Our Proposed CPU Scheduling Algorithm CPU scheduling is a technique that fully utilizes the CPU by allowing one process to use it while another process is in a waiting state due to a lack of resources. The ultimate object of CPU scheduling algorithm is to maximize CPU utilization, maximum throughput, less average waiting time, less response time and less turnaround time. In our proposed algorithm, a new scheduling algorithm based on round robin and preemptive priority scheduling is designed and implemented. Here our new algorithm provides less starvation problem and less response time.
We want to provide an algorithm that will lessen the starvation problem while simultaneously reducing response time. We are going to take a time slice so that each process receives an equal amount of time. Every process will be given a priority rating (lower number means higher priority) and their last active time will be tracked here. The process which was active in the CPU a long time ago will have a higher chance of getting the CPU. The priority of the process is also taken into consideration. So, the two criteria for choosing which process will use the CPU for the duration of a time slice are: (i) last active time in the CPU and (ii) priority describing number. If a process has higher priority, and it was active a long time ago, this combination will result in higher chance of getting the CPU. Lower priority or recently run processes will have a lower chance of getting the CPU. For processes that have just arrived, the last active time of these processes are set to negative infinity, so they get the CPU at the earliest time possible. If multiple processes arrive at the same time with varying priority, they all get the CPU one after another depending on their priority. Thus, we will experience less starvation and a faster response time as a result.
