diff --git a/simulator.c b/simulator.c index e117924..39a5411 100644 --- a/simulator.c +++ b/simulator.c @@ -8,6 +8,7 @@ enum pstate { WAITING, READY, + RUNNING, FINISHED }; @@ -18,13 +19,25 @@ struct pinfo { int priority; int wait_time; - int completion_time; + int turnaround_time; int remaining_time; + int n_preempted; enum pstate state; struct pinfo * next_pinfo; }; +int n_processes(struct pinfo * head) { + int n = 0; + + while (head != NULL) { + n++; + head = head->next_pinfo; + } + + return n; +} + struct perf_info { int total_time; int total_nr_ctxt_switch; @@ -44,7 +57,7 @@ void print_pinfo(struct pinfo * info) { printf(" Execution time: %d\n", info->execution_time); printf(" Priority: %d\n", info->priority); printf(" Wait time: %d\n", info->wait_time); - printf(" Completion time: %d\n", info->completion_time); + printf(" Turnaround time: %d\n", info->turnaround_time); printf(" Remaining time: %d\n", info->remaining_time); printf(" NEXT -> %p\n", info->next_pinfo); printf("}>\n"); @@ -64,8 +77,9 @@ struct pinfo * create_process(int id, int arrival_time, int execution_time, int info->execution_time = execution_time; info->priority = priority; info->wait_time = 0; - info->completion_time = 0; + info->turnaround_time = 0; info->remaining_time = execution_time; + info->n_preempted = 0; info->state = WAITING; info->next_pinfo = NULL; return info; @@ -83,8 +97,8 @@ struct perf_info schedule_FCFS(struct pinfo * processes) { wait_time = 0; } process->wait_time = wait_time; - process->completion_time = process->execution_time + process->wait_time; - current_time = process->arrival_time + process->completion_time; + process->turnaround_time = process->execution_time + process->wait_time; + current_time = process->arrival_time + process->turnaround_time; process = process->next_pinfo; } @@ -93,6 +107,201 @@ struct perf_info schedule_FCFS(struct pinfo * processes) { return perf; } +struct prio_list { + struct pinfo ** proc; + int length; +}; + +/** + * Pops and returns the last element (highest priority) of the given priority list + * + * Returns NULL if the list is empty + */ +struct pinfo * prio_list_pop(struct prio_list * list) { + if (list->length == 0) { + return NULL; + } + + list->length--; + return *(list->proc + list->length); +} + +/** + * Adds the given process in the priority list at + * the appropriate place (according to its priority) + */ +void prio_list_add(struct prio_list * list, struct pinfo * proc) { + struct pinfo * proc2; + int idx = 0; + + // Find first element (from the right) with lower priority + for (int i=list->length-1; i>=0; i--) { + proc2 = *(list->proc + i); + if (proc2->priority > proc->priority) { + idx = i+1; + break; + } + } + // Shift elements + for (int j=list->length-1; j>=idx; j--) { + *(list->proc + j + 1) = *(list->proc + j); + } + *(list->proc + idx) = proc; + list->length++; +} + +/** + * Creates a new priority list + */ +struct prio_list * create_prio_list(int max_size) { + struct pinfo ** processes = (struct pinfo **) malloc(sizeof(struct pinfo *) * max_size); + struct prio_list * list = (struct prio_list *) malloc(sizeof(struct prio_list)); + list->length = 0; + list->proc = processes; + return list; +} + +/** + * Returns the last element (highest priority) of the given priority list + */ +struct pinfo * prio_list_last(struct prio_list * list) { + return *(list->proc + list->length - 1); +} + +/** + * Prints the pids of the processes in the given priority list + */ +void prio_list_print(struct prio_list * list) { + printf("queue: "); + for (int i=0; i < list->length; i++) { + if (i != 0) { + printf(", "); + } + printf("%d", (*(list->proc + i))->id); + } + printf("\n"); +} + +struct perf_info schedule_Pr(struct pinfo * processes) { + struct perf_info perf = {0, 0, 0}; + + int current_time = 0; + struct pinfo * current = NULL; + struct pinfo * next = processes; + + int N = n_processes(processes); + printf("N = %d\n", N); + + struct prio_list * queue = create_prio_list(N); + + int finished = 0; + + while (finished != N) { + printf("\nCurrent time: %d / ", current_time); + if (current != NULL) { + printf("Current: %d / ", current->id); + } else { + printf("Current: none / "); + } + if (next != NULL) { + printf("Next: %d\n", next->id); + } else { + printf("Next: none\n"); + } + + if (current == NULL) { + printf("No running process: running %d\n", next->id); + current = next; + current->state = RUNNING; + next = next->next_pinfo; + + } else if (next != NULL) { + next->state = READY; + prio_list_print(queue); + printf("Processing next process (%d)\n", next->id); + + // If current finished before next + while (current != NULL && current_time + current->remaining_time <= next->arrival_time) { + printf(" Process %d finished before next\n", current->id); + current->state = FINISHED; + current_time += current->remaining_time; + current->turnaround_time = current_time - current->arrival_time; + current->remaining_time = 0; + finished++; + current = prio_list_pop(queue); + } + + if (current != NULL) { + printf("Removing time from current process\n"); + current->remaining_time -= next->arrival_time - current_time; + current->turnaround_time += next->arrival_time - current_time; + } + if (next->arrival_time > current_time) { + current_time = next->arrival_time; + } + next->state = READY; + + // If no running process, immediately run next process + if (current == NULL) { + printf("Queue is empty, running next process %d\n", next->id); + current = next; + current->state = RUNNING; + next = next->next_pinfo; + + } else if (next->priority < current->priority) { + // Preempt current process + printf("Next process (%d) has higher priority\n", next->id); + if (current->state == RUNNING) { + printf(" Preempting current process (%d)\n", current->id); + current->n_preempted++; + current_time += CNTXT_SWITCH; + perf.total_nr_ctxt_switch++; + } + current->state = READY; + prio_list_add(queue, current); + + // Run process with higher priority + current = next; + current->state = RUNNING; + next = next->next_pinfo; + } else { + printf("Adding next process (%d) to list\n", next->id); + prio_list_add(queue, next); + next = next->next_pinfo; + } + if (current != NULL) { + current->state = RUNNING; + } + + + } else { + printf("No new processes, emptying queue\n"); + while (current != NULL) { + printf("Completing process %d\n", current->id); + current->state = FINISHED; + current_time += current->remaining_time; + current->turnaround_time = current_time - current->arrival_time; + current->remaining_time = 0; + finished++; + current = prio_list_pop(queue); + if (current != NULL) { + current->state = RUNNING; + } + } + } + } + perf.total_time = current_time; + perf.total_time_ctxt_switch = perf.total_nr_ctxt_switch * CNTXT_SWITCH; + + return perf; +} + +void compute_waiting_time(struct pinfo * processes) { + while (processes != NULL) { + processes->wait_time = processes->turnaround_time - processes->execution_time; + processes = processes->next_pinfo; + } +} struct pinfo * read_file() { FILE * file = fopen("tasks.csv", "r"); @@ -154,7 +363,10 @@ void free_processes(struct pinfo * next) { int main() { struct pinfo * processes = read_file(); - struct perf_info perf = schedule_FCFS(processes); + //struct perf_info perf = schedule_FCFS(processes); + struct perf_info perf = schedule_Pr(processes); + + compute_waiting_time(processes); //write_file(processes, &perf); print_processes(processes);