307 lines
7.6 KiB
C
307 lines
7.6 KiB
C
#include "../includes/sched.h"
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#include <errno.h>
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#include <pthread.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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struct task_info {
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void *closure;
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taskfunc f;
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};
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struct scheduler {
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/* Premier élément du deque (dernier ajouter) */
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int *bottom;
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/* Variable de conditions pour reveillé les threads au besoin */
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pthread_cond_t cond;
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/* Mutex qui protège les piles */
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pthread_mutex_t mutex;
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/* Nombre de threads instanciés */
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int nthreads;
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/* Compteur des threads dormants */
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int nthsleep;
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/* Taille des piles */
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int qlen;
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/* Piles de tâches */
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struct task_info **tasks;
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/* Liste des threads */
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pthread_t *threads;
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/* Dernier élément du deque (premier ajouter) */
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int *top;
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};
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/* Lance une tâche de la pile */
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void *sched_worker(void *);
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/* Nettoie les opérations effectuées par l'initialisation de l'ordonnanceur */
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int sched_init_cleanup(struct scheduler, int);
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/* Récupère l'index du thread courant */
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int current_thread(struct scheduler *);
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int
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sched_init(int nthreads, int qlen, taskfunc f, void *closure)
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{
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static struct scheduler sched;
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sched.bottom = NULL;
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sched.tasks = NULL;
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sched.threads = NULL;
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sched.top = NULL;
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if(qlen <= 0) {
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fprintf(stderr, "qlen must be greater than 0\n");
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return -1;
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}
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sched.qlen = qlen + 1; // circular buffer
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if(nthreads < 0) {
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fprintf(stderr, "nthreads must be greater than 0\n");
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return -1;
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} else if(nthreads == 0) {
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nthreads = sched_default_threads();
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}
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sched.nthreads = 0;
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sched.nthsleep = 0;
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// Initialisation du mutex
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if(pthread_mutex_init(&sched.mutex, NULL) != 0) {
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fprintf(stderr, "Can't init mutex\n");
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return sched_init_cleanup(sched, -1);
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}
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// Initialisation variable de condition
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if(pthread_cond_init(&sched.cond, NULL) != 0) {
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fprintf(stderr, "Can't init varcond\n");
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return sched_init_cleanup(sched, -1);
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}
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// Initialisation du curseur suivant l'état de la pile de chaque processus
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if(!(sched.bottom = malloc(nthreads * sizeof(int)))) {
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perror("Cursor bottom stack");
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return sched_init_cleanup(sched, -1);
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}
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if(!(sched.top = malloc(nthreads * sizeof(int)))) {
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perror("Cursor top stack");
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return sched_init_cleanup(sched, -1);
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}
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for(int i = 0; i < nthreads; ++i) {
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sched.bottom[i] = 0;
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sched.top[i] = 0;
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}
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// Allocation mémoire pour la pile de chaque processus
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if(!(sched.tasks = malloc(nthreads * sizeof(struct task_info *)))) {
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perror("Deque list");
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return sched_init_cleanup(sched, -1);
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}
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for(int i = 0; i < nthreads; ++i) {
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if(!(sched.tasks[i] = malloc(qlen * sizeof(struct task_info)))) {
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fprintf(stderr, "Deque for thread %d: %s\n", i, strerror(errno));
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return sched_init_cleanup(sched, -1);
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}
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}
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// Initialise l'aléatoire
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srand(time(NULL));
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// Créer les threads
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if(!(sched.threads = malloc(nthreads * sizeof(pthread_t)))) {
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perror("Threads");
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return sched_init_cleanup(sched, -1);
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}
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// Ajoute la tâche initiale
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if(sched_spawn(f, closure, &sched) < 0) {
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fprintf(stderr, "Can't create the initial task\n");
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return sched_init_cleanup(sched, -1);
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}
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// Démarre les threads
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for(int i = 0; i < nthreads; ++i) {
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if(pthread_create(&sched.threads[i], NULL, sched_worker, &sched) != 0) {
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fprintf(stderr, "Can't create the thread %d\n", i);
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if(i > 0) {
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fprintf(stderr, ", cancelling already created threads...\n");
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for(int j = 0; j < i; ++j) {
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if(pthread_cancel(sched.threads[j]) != 0) {
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fprintf(stderr, "Can't cancel the thread %d\n", j);
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}
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}
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} else {
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fprintf(stderr, "\n");
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}
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return sched_init_cleanup(sched, -1);
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}
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pthread_mutex_lock(&sched.mutex);
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sched.nthreads++;
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pthread_mutex_unlock(&sched.mutex);
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}
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for(int i = 0; i < nthreads; ++i) {
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if((pthread_join(sched.threads[i], NULL) != 0)) {
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fprintf(stderr, "Can't wait the thread %d\n", i);
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return sched_init_cleanup(sched, -1);
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}
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}
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return sched_init_cleanup(sched, 1);
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}
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int
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sched_init_cleanup(struct scheduler s, int ret_code)
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{
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pthread_mutex_destroy(&s.mutex);
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pthread_cond_destroy(&s.cond);
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if(s.tasks) {
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for(int i = 0; i < s.nthreads; ++i) {
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if(s.tasks[i]) {
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free(s.tasks[i]);
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s.tasks[i] = NULL;
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}
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}
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free(s.tasks);
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s.tasks = NULL;
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}
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if(s.threads) {
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free(s.threads);
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s.threads = NULL;
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}
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if(s.bottom) {
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free(s.bottom);
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s.bottom = NULL;
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}
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if(s.top) {
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free(s.top);
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s.top = NULL;
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}
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return ret_code;
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}
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int
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current_thread(struct scheduler *s)
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{
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pthread_t current = pthread_self();
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pthread_mutex_lock(&s->mutex);
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for(int i = 0; i < s->nthreads; ++i) {
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if(pthread_equal(s->threads[i], current)) {
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pthread_mutex_unlock(&s->mutex);
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return i;
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}
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}
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pthread_mutex_unlock(&s->mutex);
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return -1;
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}
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int
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sched_spawn(taskfunc f, void *closure, struct scheduler *s)
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{
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int th;
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if((th = current_thread(s)) < 0) {
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th = 0;
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}
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pthread_mutex_lock(&s->mutex);
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int next = (s->bottom[th] + 1) % s->qlen;
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if(next == s->top[th]) {
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pthread_mutex_unlock(&s->mutex);
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fprintf(stderr, "Stack is full\n");
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errno = EAGAIN;
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return -1;
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}
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s->tasks[th][s->bottom[th]] = (struct task_info){closure, f};
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s->bottom[th] = next;
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pthread_mutex_unlock(&s->mutex);
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return 0;
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}
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void *
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sched_worker(void *arg)
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{
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struct scheduler *s = (struct scheduler *)arg;
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// Récupère le processus courant (index tableau)
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int curr_th;
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while((curr_th = current_thread(s)) < 0);
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struct task_info task;
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int found;
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while(1) {
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found = 0;
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pthread_mutex_lock(&s->mutex);
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if(s->top[curr_th] != s->bottom[curr_th]) {
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found = 1;
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s->bottom[curr_th] = (s->bottom[curr_th] - 1 + s->qlen) % s->qlen;
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task = s->tasks[curr_th][s->bottom[curr_th]];
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}
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if(!found) {
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// Vol car aucune tâche trouvée
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for(int i = 0, k = rand() % (s->nthreads + 1), target;
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i < s->nthreads; ++i) {
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target = (i + k) % s->nthreads;
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if(s->top[target] != s->bottom[target]) {
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// Tâche trouvée
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found = 1;
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s->bottom[target] =
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(s->bottom[target] - 1 + s->qlen) % s->qlen;
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task = s->tasks[target][s->bottom[target]];
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break;
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}
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}
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// Aucune tâche à faire
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if(!found) {
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s->nthsleep++;
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// Ne partir que si tout le monde dort
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if(s->nthsleep >= s->nthreads) {
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pthread_cond_broadcast(&s->cond);
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pthread_mutex_unlock(&s->mutex);
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break;
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}
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pthread_cond_wait(&s->cond, &s->mutex);
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s->nthsleep--;
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pthread_mutex_unlock(&s->mutex);
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continue;
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}
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}
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pthread_cond_broadcast(&s->cond);
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pthread_mutex_unlock(&s->mutex);
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// Exécute la tâche
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task.f(task.closure, s);
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}
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return NULL;
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}
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