Ajout de l'exo 3 TP 6

TP6/Exo3/exo3.c

@@ -0,0 +1,74 @@
+#include <assert.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+static inline double tstamp(void)
+{
+    struct timespec tv;
+    clock_gettime(CLOCK_REALTIME, &tv);
+    return tv.tv_sec + tv.tv_nsec * 1.0e-9;
+}
+
+typedef struct thread_arg
+{
+    long int start;
+    long int limit;
+    long int inc;
+    long int S;
+} thread_arg;
+
+void *slice(void *arg)
+{
+    thread_arg *a = (thread_arg *)arg;
+    long int S = 0;
+
+    for (long int i = a->start; i <= a->limit; i = i + a->inc)
+    {
+        S += i;
+    }
+    a->S = S;
+    return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+    long int N, M, S = 0;
+    double t1, t2;
+    thread_arg *args;
+    pthread_t *ths;
+
+    assert(argc >= 3);
+    N = strtol(argv[1], NULL, 0);
+    M = strtol(argv[2], NULL, 0);
+    t1 = tstamp();
+
+    args = (thread_arg *)calloc(M, sizeof(thread_arg));
+    assert(args != NULL);
+
+    ths = (pthread_t *)calloc(M, sizeof(pthread_t));
+    assert(ths != NULL);
+
+    for (int i = 0; i < M; i++)
+    {
+        args[i].inc = M;
+        args[i].limit = N;
+        args[i].start = i + 1;
+        pthread_create(ths + i, NULL, slice, (void *)(args + i));
+    }
+
+    for (int i = 0; i < M; i++)
+    {
+        pthread_join(ths[i], NULL);
+        S += args[i].S;
+    }
+
+    assert(S == N * (N + 1) / 2);
+
+    t2 = tstamp();
+    printf("S = %ld\n", S);
+    printf("t = %lf\n", t2 - t1);
+
+    return 0;
+}