amrahmades / round_robin_algorithm

simulation of round robin algorithm

Round_Robin_algorithm

simulation of round robin algorithm

  -- The following information has been collected from the web -- 

Round-robin (RR): is one of the algorithms employed by process and network schedulers in computing. As the term is generally used, time slices are assigned to each process in equal portions and in circular order, handling all processes without priority (also known as cyclic executive).

Round-robin scheduling is simple, easy to implement . round-robin scheduling can also be applied to other scheduling problems, such as data packet scheduling in computer networks. It is an Operating System concept.

The name of the algorithm comes from the round-robin principle known from other fields, where each person takes an equal share of something in turn.

Each process gets a small unit of CPU time (time quantum q), usually 10-100 milliseconds. After this time has elapsed, the process is preempted and added to the end of the ready queue.

•  If there are n processes in the ready queue and the time quantum is q, then each process
gets 1/n of the CPU time in chunks of at most q time units at once. No process waits more
than (n-1)q time units.
•  Timer interrupts every quantum to schedule next process
•  Performance
•  q large  FIFO
•  q small  q must be large with respect to context switch,
   otherwise overhead is too high

Compilation and Usage

To download > open terminal :

cd ~/Desktop
git clone https://github.com/momaiaz/Round_Robin_algorithm.git

Compilers recommended :

• Linux: g++4.8

• Not tested on windwos but supposed to work

compilation steps :

cd Round_Robin_algorithm/
g++ -std=c++11 -o RoundRobin.out RoundRobin.cpp

now we have a file called "RoundRobin.out" which is the executive program . run program using this pattern

 ./RoundRobin.out <input.text> <output.text>

• <input.text> file contain process information
• <output.text> file target which is store output ... It will appear on the screen as well

input file format:

  <processName>$<arival_time>$<burst_time>

Example :

  p1$0$27
  p2$1$7
  p3$2$10
  p5$5$20
  p4$300$6

run ?

======================
Process name: cal
Process arrival time: 0
Process burst time: 27
======================
======================
Process name: office
Process arrival time: 2
Process burst time: 7
======================
======================
Process name: media
Process arrival time: 60
Process burst time: 10
======================

Enter quantum time : 3

|0==[cal]==3||3==[office]==6||6==[cal]==9||9==[office]==12||12==[cal]==15|
|15==[office]==16||16==[cal]==19||19==[cal]==22||22==[cal]==25||25==[cal]==28|
|28==[cal]==31||31==[cal]==34||34==[idle]==60||60==[media]==63||63==[media]==66|
|66==[media]==69||69==[media]==70|

Average Turn Time = 19.3333
Average WaitingTime = 4.66667