Priority Scheduling Program In C With Gantt Chart
Introduction
Priority scheduling is a popular algorithm used in operating systems to schedule processes according to their priority level. This algorithm assigns a priority to each process, and the scheduler always selects the process with the highest priority for execution. In this article, we will discuss how to implement priority scheduling in C programming language and visualize the scheduling process using a Gantt chart.
What is Priority Scheduling?
Priority scheduling is a scheduling algorithm that assigns priorities to each process based on their importance. The scheduler always selects the process with the highest priority for execution. In this way, processes with high importance get executed first, and low priority processes are executed later. This algorithm is used in many operating systems, including Windows, Linux, and macOS.
Implementing Priority Scheduling in C
To implement priority scheduling in C programming language, we need to define a struct that represents a process. This struct should contain the process ID, arrival time, burst time, and priority. We will use an array of such structs to represent all the processes in the system.
Here is the code snippet for defining the process struct:
struct process {int pid;int arrival_time;int burst_time;int priority;};Once we have defined the process struct, we can define an array of processes and initialize it with some sample data. Here is an example:
struct process processes[] = {{1, 0, 5, 3},{2, 1, 3, 1},{3, 2, 8, 4},{4, 3, 6, 2},{5, 4, 4, 5}};Now that we have initialized the process array, we can write the scheduling algorithm. The algorithm should select the process with the highest priority and execute it for a certain time slice. Then, it should select the next process with the highest priority and execute it for another time slice. This process should continue until all the processes have been executed.
Here is the code snippet for implementing the priority scheduling algorithm:
void priority_scheduling(struct process processes[], int n) {int total_time = 0;int i, j;struct process temp;for (i = 0; i < n-1; i++) {for (j = i+1; j < n; j++) {if (processes[i].priority < processes[j].priority) {temp = processes[i];processes[i] = processes[j];processes[j] = temp;}}}printf("Gantt Chart:\n");for (i = 0; i < n; i++) {printf("%d ", processes[i].pid);total_time += processes[i].burst_time;processes[i].burst_time = 0;}printf("\nTotal Execution Time: %d\n", total_time);}This code sorts the processes array in descending order of priority and then executes each process in order. It also prints a Gantt chart that shows the execution order of the processes.
Visualizing Priority Scheduling with Gantt Chart
A Gantt chart is a graphical representation of a schedule that shows the start and end times of each task. In the case of priority scheduling, we can use a Gantt chart to visualize the order in which the processes are executed.
Here is an example Gantt chart for the sample data we used earlier:
The Gantt chart shows the order in which the processes are executed and the total execution time. This chart can be very useful for understanding the scheduling algorithm and for debugging any issues that may arise.
Conclusion
In this article, we have discussed how to implement priority scheduling in C programming language and visualize the scheduling process using a Gantt chart. Priority scheduling is a popular algorithm used in operating systems to schedule processes according to their priority level. This algorithm assigns a priority to each process, and the scheduler always selects the process with the highest priority for execution. By using a Gantt chart, we can visualize the order in which the processes are executed and the total execution time. This can be very useful for understanding the scheduling algorithm and for debugging any issues that may arise.