vector_t v[2 * MAX_THREADS]; // used to ensure print outs make sense pthread_mutex_t print_lock = PTHREAD_MUTEX_INITIALIZER; void usage(char *prog) { fprintf(stderr, "usage: %s [-d (turn on deadlocking behavior)] [-l loops] [-n num_threads] [-t (do timing)] [-v (for verbose)]\n", prog); exit(1); } // only called by one thread (not thread-safe) void vector_init(vector_t *v, int value) { int i; for (i = 0; i < VECTOR_SIZE; i++) { v->values[i] = value; } Pthread_mutex_init(&v->lock, NULL); } // only called by one thread (not thread-safe) void vector_print(vector_t *v, char *str) { int i; for (i = 0; i < VECTOR_SIZE; i++) { printf("%s[%d] %d\n", str, i, v->values[i]); } } void print_info(int call_return, int thread_id, int v0, int v1) { if (verbose == 0) return; Pthread_mutex_lock(&print_lock); int j; for (j = 0; j < thread_id; j++) printf(" "); if (call_return) printf("<-add(%d, %d)\n", v0, v1); else printf("->add(%d, %d)\n", v0, v1); Pthread_mutex_unlock(&print_lock); } typedef struct __thread_arg_t { int tid; int vector_add_order; int vector_0; int vector_1; } thread_arg_t; void *worker(void *arg) { thread_arg_t *args = (thread_arg_t *) arg; int i, v0, v1; for (i = 0; i < loops; i++) { if (args->vector_add_order == 0) { v0 = args->vector_0; v1 = args->vector_1; } else { v0 = args->vector_1; v1 = args->vector_0; } print_info(0, args->tid, v0, v1); vector_add(&v[v0], &v[v1]); print_info(1, args->tid, v0, v1); } return NULL; } int main(int argc, char *argv[]) { opterr = 0; int c; while ((c = getopt (argc, argv, "l:n:vtdp")) != -1) { switch (c) { case 'l': loops = atoi(optarg); break; case 'n': num_threads = atoi(optarg); break; case 'v': verbose = 1; break; case 't': do_timing = 1; break; case 'd': cause_deadlock = 1; break; case 'p': enable_parallelism = 1; break; default: usage(argv[0]); } } assert(num_threads < MAX_THREADS); pthread_t pid[MAX_THREADS]; thread_arg_t args[MAX_THREADS]; int i; for (i = 0; i < num_threads; i++) { args[i].tid = i; if (enable_parallelism == 0) { args[i].vector_0 = 0; args[i].vector_1 = 1; } else { args[i].vector_0 = i * 2; args[i].vector_1 = i * 2 + 1; } if (cause_deadlock && i % 2 == 1) args[i].vector_add_order = 1; else args[i].vector_add_order = 0; } for (i = 0; i < 2 * MAX_THREADS; i++) vector_init(&v[i], i); double t1 = Time_GetSeconds(); for (i = 0; i < num_threads; i++) Pthread_create(&pid[i], NULL, worker, (void *) &args[i]); for (i = 0; i < num_threads; i++) Pthread_join(pid[i], NULL); double t2 = Time_GetSeconds(); fini(); if (do_timing) { printf("Time: %.2f seconds\n", t2 - t1); } //vector_print(&v[0], "v1"); //vector_print(&v[1], "v2"); return 0; }

Instructions for Exercise