代写data编程、代写C/C++编程

日期：2022-09-30 10:19

Programming Assignment

OS Scheduling

What Will We Do?

• In this project we will test several scheduling

algorithms

Scheduling

Input

file

Scheduling

algorithm

output file

(integer )

./scheduling inp1.txt 0

Your Source Code

• scheduling.c

• compile with:

gcc –Wall –o scheduling –std=c99 scheduling.c

Input File

• The first line in the file is the total number of

processes.

• Each process will be represented by 4 integers:

A B C D:

– A: process ID

– B: CPU time

– C: I/O time

– Arrival time

0.5 CPU time I/O time 0.5 CPU time

How time is distributed for a process

Note: We will use integers, not floating point.

In case (0.5 * CPU Time) is float, round to following

Note: cycle (e.g. if cpu time is 7 then 7/2 = 3.5 -> 4). If more than one process

arrives at the same time, give

preference to the one with

lower ID. All times are in cycles

Scheduling Algorithms

• 0: First-Come-First-Served (nonpreemptive)

– Queue of ready processes

– Newly arriving processes are added to the end of

the queue.

– When a process is blocked, due to I/O, and then

becomes ready, it is added to the end of the

queue.

– If two processes happen to be ready at the same

time, give preference to the one with lower ID.

Scheduling Algorithms

• 1: Round-Robin with quantum 2

– Another process scheduled if one of the following

occurs:

• Current running process terminates

• Current running process is blocked on I/O

• Current running process ran for 2 cycles

– You can think of RR as a queue of ready processes.

When a process goes from running to ready, it moves

to the back of the queue.

– If two processes become Ready at the same time, give

preference to the one with smaller ID

Scheduling Algorithms

• 2: Shortest remaining job first (preemptive)

– At each cycle, you calculate the remaining CPU

time for all ready/running processes and run the

one with shortest reaming time

– If several processes have the same remaining CPU

time, give preference to the process with lower ID.

Output

• You output a file with name: s-inputfilename.txt

– inputfilename is the name of the input file without

the extension

– s is the scheduling algorithm:0, 1, or 2

– Example: if input file is inp1.txt, your output file for

FCFS shall be: 0-inp1.txt

• Your output file has two parts

– Timing snapshot (starting from cycle 0)

– Statistics

Output

• Timing snapshot: at every line show:

– Cycle number

– State of each process (running, ready, or blocked)

• example: 1:blocked (i.e. process 1 is in blocked state)

• Print processes, in the same line, ordered by their process ID

– Be careful: do not show processes that have not yet arrived, or

those that have terminated.

• Statistics:

– Finishing time (i.e. last cycle)

– CPU utilization ( #cycles CPU was doing work / total number of

cycles)

• When there is a cycle where none of the processes is running, then

the CPU is considered idle.

– For each process:

• Turnaround time (i.e. cycle this process finished – cycle it started + 1)

Example

Process ID

CPU Time I/O Time

Arrival Time

3

0 2 2 0

1 2 1 5

2 2 1 3

input file

# processes

Example

0: FCFS

Your

Program

0 0:running

1 0:blocked

2 0:blocked

3 0:running 2:ready

4 2:running

5 1:running 2:blocked

6 1:blocked 2:running

7 1:running

(empty line)

Finishing time: 7

CPU utilization: 0.75

Turnaround process 0: 4

Turnaround process 1: 3

Turnaround process 2: 4

Clock cycle

State of

each process

3

0 2 2 0

1 2 1 5

2 2 1 3

input file

What To Submit

Your source code: single file with the name

scheduling.c

Avoid The Following Mistakes

(Penalty applied for each)

• Code does not run on CIMS machines (-5)

• Late submission (-20% for each day)

• Output with different format (-5)

• The work is not your own (zero!)

Excuses not Accepted

• I submitted the wrong file.

• I submitted one minute after the deadline.

– We highly suggest that you upload a version, even

if not yet complete, each time you implement

something and do not wait till you finish the

whole program.

One last thing

• To help you start, we are proving you with a C

file (skeleton-lab1.c) that:

– Reads arguments from command line

– Checks that the arguments are correct

– Forms the name of the output file

• You can use this file, part of it, or none at all. It

is up to you as long as your submitted

program works correctly.

To test your code

• You are provided with two zip files

2processes.zip and 3processes.zip

– Each one contains an input file (2processes.txt and

3processes.txt) and the output for each of the

three different scheduling algorithms

• You can also use these example files to

formulate other test cases, solve them on a

piece of paper first, then check the output.

All the Best!