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CPU-Scheduler

simulating scheduling algorithms of operating system for processes e.g. Priority Scheduling, Multi Level Scheduling, ...

  • @ASCK-TEAM

Getting Started

This repository exposed here, is actually a university project of the course operating system

And implemented with Java language.

Documentation

The hierarchy display of the classes is demonstrated here:

----cpuscheduler

-----------|

-----------src

------------------|

------------------Process //data of each process e.g. start time, burst time, ...

------------------CPU //cpu for simulating schedule

------------------Scheduler //abstract class for primitive methods and fields

------------------Sch_FCFS //First Come First Serve Scheduler

------------------Sch_SJF //Shortest Job First Scheduler (can be preemptive)

------------------Sch_Priority //Priority Scheduler (can be preemptive)

------------------Sch_RR //Round Robin Scheduler

------------------Sch_Lottery //Lottery Scheduler

------------------Sch_Multilevel //Multi Level Scheduler (can be preemptive)

------------------FXMLDocumentController //controller for main gui

------------------SimulationController //controller for simulation gui

----/

  • Process: either a process is executing or waiting these 2 states are handled in:

    • executing(double timeNow) : consume burst time and check if process is arrived or finished.
    • waiting(double timeNow) : add to waiting time

  • CPU:

    • first all process get initialize and added to allProc and procQueue ArrayList
    • then in Simulate() cpu checks if any process if it's arrived or not then add it to readyQueue
    • then depend on the scheduler next ready process will go on cpu
    • then cpu refresh its procQueue and readyQueue to remove finished processes
    • at last cpu save the report for simulation gui and reset all scheduler data

  • Scheduler:

    • depend on the scheduler method return next process to go on cpu
    • Sch_FCFS: Priority Queue on arrival time
    • Sch_SJF: Priority Queue on burst time if preemptive is true always check for shorter burst time in queue
    • Sch_Priority: Priority Queue on priority if preemptive is true always check for shorter burst time in queue
    • Sch_RR: Priority Queue on arrival time and have additional RR list for switching between arrived processes in quantum time interval
    • Sch_Lottery: Random List of processes
    • Sch_Multilevel: List of scheduler levels return next process depend on scheduler method of first non-empty level if preemptive is true always check for non-empty levels first

NOTES

Note that simulation time unit is 0.1 so burst time or delay time must be multiple of 0.1

Note that order of each line specifies order of process arrival

Note that input format is like this for each line (Burst Time, Delay Time, Priority, Level)

  • Burst Time : the duration for which a process gets control of the CPU.
  • Delay Time : the duration for which a process takes to come after the previous process for example: first process delay time is 1 so it will arrive at time 1 and second process delay time is 3 so it will arrive at time 4.
  • Priority : priority of a process (for Priority and Lottery Scheduler but it can't be omitted from input)
  • Level : level of a process (for Multi Level Scheduler but it can't be omitted from input)

Note that minimum duration of context switch in this simulation is 0.4

Note that minimum duration of quantum for round robbin scheduler in this simulation is 0.2 because time unit is 0.1 and quantum can't be less than time unit


Results

Input Tabel:

Process Name Arrival Time Execute Time Level
1 0 5 1
2 1 8 2
3 3 7 2
4 4 3 1
5 5 3 1
6 8 11 2
7 15 3 1
8 25 4 1

For Example we are Scheduling process in Multi Level non-preemptive(l1:FCFS, l2 FCFS) below (input.txt file)

First we enter process information and choose scheduling alghorithm then press Run button

Wait for simulation to end

Now you can see the results

Authors

Org.

Team

  • ASCK TEAM

License

This project is licensed under the MIT License - see the LICENSE file for details