CPU Scheduling Simulator

Overview

This program simulates a Multi-Level Feedback Queue (MLFQ) scheduling policy on a multi-CPU system. It's designed to emulate the behavior of scheduling tasks on multiple CPUs using threads, where each CPU is represented by a thread. The program compares the performance of different scheduling policies using this simulation.

Features

• Implements MLFQ scheduling policies.
• Simulates multi-CPU system using threads.
• Each "CPU" thread handles one task at a time.
• Supports I/O-bound and CPU-bound tasks.
• Includes functionality to simulate I/O operations and task sleeping.
• Priority levels and quantum lengths are configurable.
• Measures and reports average turnaround time and response time for each task type.

Requirements

• C compiler (GCC recommended)
• POSIX compliant environment
• sys/queue.h for queue operations (included in most Unix-like systems)

Configuration

• Priority Levels: 3
• Quantum Length: 50 microseconds
• Time Allotment: 200 microseconds before lowering a task's priority
• S Value: Time value for moving jobs to the topmost queue (modifiable for system analysis)

Compilation

Compile the program with GCC or a similar C compiler. For example:

gcc -o cpuScheduling cpuScheduling.c -lpthread

or with make:

make

USAGE

The program requires three command-line arguments:

1. Number of CPUs: Number of simulated CPUs (threads).
2. S Value: Time in milliseconds between boosting all jobs to the topmost queue.
3. Task File Name: Name of the file containing the workload for the simulation.

Example Command

./cpuScheduling 4 5000 tasks.txt

Make Run

With 1,2,3,4 CPUs, and 1000ms, 3000ms, 5000ms, 7000ms boost time, on tasks.txt:

or, with make:

make run

This runs the simulator with 4 CPU threads, a boost time of 5000ms, and tasks loaded from tasks.txt.

Input File Format

The workload file should contain tasks with the following space-delimited format:

task_name task_type task_length odds_of_IO

Where:

• task_name: Name of the task.
• task_type: Type of the task (0 for short, 1 for medium, 2 for long, 3 for I/O tasks).
• task_length: Length of the task in microseconds.
• odds_of_IO: Percentage chance of the task performing an I/O operation.

DELAY Command

Use DELAY to introduce delays in task processing.

Output The program outputs the average turnaround time and response time for each type of task upon completion.

Report

Report and Analysis

Compute an average turnaround and response time for each type of task for each scheduling policy for these settings.

CPU Count: 1

S Value	Type	Avg Turnaround	Avg Response
1000	0	211573.63	211800.37
1000	1	216954.19	217151.24
1000	2	187531.72	187372.31
1000	3	263531.32	263551.00
---------	------	----------------	--------------
3000	0	213752.21	214068.42
3000	1	215071.48	215352.52
3000	2	196871.53	196866.75
3000	3	258580.23	258657.68
---------	------	----------------	--------------
5000	0	242511.11	242807.47
5000	1	244163.57	244430.76
5000	2	229267.22	229254.97
5000	3	300189.14	300312.59
---------	------	----------------	--------------
7000	0	207677.32	207915.79
7000	1	222806.52	223016.76
7000	2	191589.69	191515.25
7000	3	255252.59	255304.59

---

CPU Count: 2

S Value	Type	Avg Turnaround	Avg Response
1000	0	431768.83	545632.74
1000	1	464672.93	641883.67
1000	2	490125.16	581324.88
1000	3	491415.29	624997.64
---------	------	----------------	--------------
3000	0	383883.00	545735.63
3000	1	433415.32	639973.76
3000	2	448103.69	489432.31
3000	3	524434.36	557662.68
---------	------	----------------	--------------
5000	0	379836.21	480066.89
5000	1	375611.95	393706.33
5000	2	392070.11	428059.16
5000	3	486757.39	508347.09
---------	------	----------------	--------------
7000	0	366202.96	462865.84
7000	1	394342.41	507255.33
7000	2	462641.64	594366.91
7000	3	515516.71	561924.32

---

CPU Count: 3

S Value	Type	Avg Turnaround	Avg Response
1000	0	388006.74	633399.68
1000	1	419197.79	758816.90
1000	2	463401.57	679820.75
1000	3	476238.34	887144.41
---------	------	----------------	--------------
3000	0	424029.16	712738.95
3000	1	399145.12	627539.05
3000	2	455480.15	613403.09
3000	3	513770.23	700342.05
---------	------	----------------	--------------
5000	0	433288.04	547534.42
5000	1	523111.63	797303.90
5000	2	528513.28	658772.19
5000	3	491667.90	669676.36
---------	------	----------------	--------------
7000	0	460779.39	873390.74
7000	1	414362.86	848734.24
7000	2	482593.55	798375.84
7000	3	523083.25	570250.95

---

CPU Count: 4

S Value	Type	Avg Turnaround	Avg Response
1000	0	442996.37	1259304.95
1000	1	482773.17	921597.38
1000	2	437272.31	873597.25
1000	3	505211.70	1055764.00
---------	------	----------------	--------------
3000	0	479745.77	1187141.37
3000	1	363049.77	761021.10
3000	2	413971.05	730420.94
3000	3	510378.34	881271.36
---------	------	----------------	--------------
5000	0	367537.21	708776.42
5000	1	413579.12	904013.00
5000	2	423913.44	846142.66
5000	3	485275.77	820212.45
---------	------	----------------	--------------
7000	0	401477.38	845619.95
7000	1	424323.40	606522.95
7000	2	465334.50	901456.47
7000	3	467999.74	851627.55