multithreads.c

#include<stdio.h>
struct Thread
{
 int st; // service time
 int ft; // finish time
 int status; // thread  execution completed - 1, not completed - 0
};
struct Process
{
 int at; // arraival time
 int nt; // no of threads
 int ntc; // no of threads completed
 int status; // process completed - 1, not-completed-0
 int ft;
 struct Thread t[5];
}plist[10];
 int n,cur_time=0;
 void dispatch(int*,int*);
int main()
{
 int i,j,pid,tid;
 printf("\nEnter the number of processes : ");
 scanf("%d",&n);
 for(i=0;i<n;i++)
 {
  printf("\nEnter the details of the %d process : ",i+1);
  printf("\nEnter the arrival time : ");
  scanf("%d",&plist[i].at);
  printf("\nEnter the no of threads : ");
  scanf("%d",&plist[i].nt);
  for(j=0;j<plist[i].nt;j++)
  {
   printf("\n-->Enter the service time of thread %d: ",j);
   scanf("%d",&plist[i].t[j].st);
   plist[i].t[j].status=0;
  }
  plist[i].status=0;
  plist[i].ntc=0;
 }
 i=0;
 while(i<n) // Until all the n processess completed
 {
  dispatch(&pid,&tid); // Choose the next process and the thread within that process to run
  if(pid==-1) // If no process is available at this time
   cur_time++;
  
  else
  {
   int j;
   cur_time+=plist[pid].t[tid].st; // Update clock after the thread completed
   plist[pid].t[tid].ft=cur_time; //Update finish time of the completed thread TID
   plist[pid].ntc++; // Increment no of threads completed within the process PID
   plist[pid].t[tid].status=1; // Update the status of the thread to indicate it is completed
   if(plist[pid].ntc==plist[pid].nt) // If all the threads of the process PID are completed
   {
    plist[pid].ft=cur_time; // Update finish time of process PID
    plist[pid].status=1; // Update completion status of process PID
    i++; // Increment number of completed processes
   }
  }
 }
for(i=0;i<n;i++)
{
 printf("\nPID\tAT\tFT");
 printf("\n%d\t",i);
 printf("%d\t",plist[i].at);
 printf("%d\t",plist[i].ft);
 printf("\nThreads of process %d\n",i);
 printf("TID\tST\t\tFT");
 for(j=0;j<plist[i].nt;j++)
 {
   printf("\n%d \t",j+1);
   printf("%d \t",plist[i].t[j].st);
   printf("%d \t",plist[i].t[j].ft);
   printf("\n");
 }
}
return 0;
}
void dispatch(int *pid,int *tid)
{
 *pid=*tid=-1;
 int j,k,least=cur_time,id=-1;
 for(j=0;j<n;j++)
 {
  if(plist[j].status!=1) // Process not already completed
  {
   if(plist[j].at<=cur_time) // Process arrived within the current time
   {
    *pid=j;
    for(k=0;k<plist[j].nt;k++) // Pick a thread within that process
    {
     if(plist[j].t[k].status==0) // Thread not yet completed
     {
       *tid=k;
       return;
     }
    }
   }
  }
 }
}
/* Sample input and output
No. of processes 3
AT NO OF THREADS
P1 0 3 ST
T1 3
T2 2
T3 4

P2 3 2
T1 2
T2 5
p3 4 3
T1 1
T2 3
T3 2
t4 2*/