lab thread task 3

notxv6/barrier.c

@@ -25,12 +25,24 @@ barrier_init(void)
 static void 
 barrier()
 {
-  // YOUR CODE HERE
-  //
-  // Block until all threads have called barrier() and
-  // then increment bstate.round.
-  //
-
+  pthread_mutex_lock(&bstate.barrier_mutex); // Lock the mutex
+
+  // Increment the number of threads that have reached this round
+  bstate.nthread++;
+
+  // If not all threads have reached the barrier, wait
+  if (bstate.nthread < nthread) {
+      pthread_cond_wait(&bstate.barrier_cond, &bstate.barrier_mutex);
+  }
+
+  // If all threads have reached the barrier, increment the round and reset the counter
+  if (bstate.nthread == nthread) {
+      bstate.round++;
+      bstate.nthread = 0;
+      pthread_cond_broadcast(&bstate.barrier_cond); // Notify all waiting threads
+  }
+
+  pthread_mutex_unlock(&bstate.barrier_mutex); // Unlock the mutex
 }
 
 static void *