{"id":28015,"date":"2017-09-06T00:15:10","date_gmt":"2017-09-05T18:45:10","guid":{"rendered":"https:\/\/www.wikitechy.com\/technology\/?p=28015"},"modified":"2017-09-06T00:20:18","modified_gmt":"2017-09-05T18:50:18","slug":"program-priority-scheduling-set-1","status":"publish","type":"post","link":"https:\/\/www.wikitechy.com\/technology\/program-priority-scheduling-set-1\/","title":{"rendered":"Program for Priority Scheduling | Set 1"},"content":{"rendered":"

 <\/p>\n

Priority scheduling is a non-preemptive algorithm and one of the most common scheduling algorithms in batch systems. Each process is assigned a priority. Process with the highest priority is to be executed first and so on.
\nProcesses with the same priority are executed on first come first served basis. Priority can be decided based on memory requirements, time requirements or any other resource requirement.<\/p>\n

Implementation :<\/strong><\/p>\n

1- First input the processes with their burst time \r\n   and priority.\r\n2- Sort the processes, burst time and priority\r\n   according to the priority.\r\n3- Now simply apply FCFS algorithm.<\/pre>\n[ad type=”banner”]\n
\"Program \"\"<\/p>\n
Note: A major problem with priority scheduling is indefinite blocking or starvation. A solution to the problem of indefinite blockage of the low-priority process is aging. Aging is a technique of gradually increasing the priority of processes that wait in the system for a long period of time.<\/p>\n[ad type=”banner”]\n
C++ Programming:<\/strong><\/p>\n
 
 <\/div> 
\/\/ C++ program for implementation of FCFS\/\/ scheduling#include<bits\/stdc++.h>using namespace std; struct Process{    int pid;  \/\/ Process ID    int bt;   \/\/ CPU Burst time required    int priority; \/\/ Priority of this process}; \/\/ Function to sort the Process acc. to prioritybool comparison(Process a, Process b){    return (a.priority > b.priority);} \/\/ Function to find the waiting time for all\/\/ processesvoid findWaitingTime(Process proc[], int n,                     int wt[]){    \/\/ waiting time for first process is 0    wt[0] = 0;     \/\/ calculating waiting time    for (int  i = 1; i < n ; i++ )        wt[i] =  proc[i-1].bt + wt[i-1] ;} \/\/ Function to calculate turn around timevoid findTurnAroundTime( Process proc[], int n,                         int wt[], int tat[]){    \/\/ calculating turnaround time by adding    \/\/ bt[i] + wt[i]    for (int  i = 0; i < n ; i++)        tat[i] = proc[i].bt + wt[i];} \/\/Function to calculate average timevoid findavgTime(Process proc[], int n){    int wt[n], tat[n], total_wt = 0, total_tat = 0;     \/\/Function to find waiting time of all processes    findWaitingTime(proc, n, wt);     \/\/Function to find turn around time for all processes    findTurnAroundTime(proc, n, wt, tat);     \/\/Display processes along with all details    cout << "\\nProcesses  "<< " Burst time  "         << " Waiting time  " << " Turn around time\\n";     \/\/ Calculate total waiting time and total turn    \/\/ around time    for (int  i=0; i<n; i++)    {        total_wt = total_wt + wt[i];        total_tat = total_tat + tat[i];        cout << "   " << proc[i].pid << "\\t\\t"             << proc[i].bt << "\\t    " << wt[i]             << "\\t\\t  " << tat[i] <<endl;    }     cout << "\\nAverage waiting time = "         << (float)total_wt \/ (float)n;    cout << "\\nAverage turn around time = "         << (float)total_tat \/ (float)n;} void priorityScheduling(Process proc[], int n){    \/\/ Sort processes by priority    sort(proc, proc + n, comparison);     cout<< "Order in which processes gets executed \\n";    for (int  i = 0 ; i <  n; i++)        cout << proc[i].pid <<" " ;     findavgTime(proc, n);} \/\/ Driver codeint main(){    Process proc[] = {{1, 10, 2}, {2, 5, 0}, {3, 8, 1}};    int n = sizeof proc \/ sizeof proc[0];    priorityScheduling(proc, n);    return 0;}<\/code><\/pre> <\/div>\n
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Output:<\/strong><\/p>\n
Order in which processes gets executed \r\n1 3 2 \r\nProcesses  Burst time  Waiting time  Turn around time\r\n 1\t\t10\t 0\t\t 10\r\n 3\t\t8\t 10\t\t 18\r\n 2\t\t5\t 18\t\t 23\r\n\r\nAverage waiting time = 9.33333\r\nAverage turn around time = 17\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
Program for Priority Scheduling | Set  1-  Operating System – Priority scheduling is a non-preemptive algorithm and one of the most common scheduling<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[71771,82275],"tags":[82523,82521,82522,82525,82520,82524,82469],"class_list":["post-28015","post","type-post","status-publish","format-standard","hentry","category-cs-subjects","category-operating-systems","tag-algorithm-for-priority-scheduling","tag-c-program-for-round-robin-scheduling","tag-non-preemptive-priority-scheduling-program-in-c-with-arrival-time","tag-preemptive-sjf-scheduling-program-in-c","tag-priority-scheduling-program-in-c-with-arrival-time","tag-priority-scheduling-program-in-c","tag-sjf-scheduling-program-in-c"],"_links":{"self":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/28015","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/comments?post=28015"}],"version-history":[{"count":0,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/28015\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/media?parent=28015"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/categories?post=28015"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/tags?post=28015"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}