+#ifdef HAVE_FUTEX_H
+ int myflag = parmap->done;
+ __sync_fetch_and_add(&parmap->thread_counter, 1);
+ if (parmap->thread_counter < parmap->num_workers) {
+ /* wait for all workers to be ready */
+ futex_wait(&parmap->done, myflag);
+ }
+#endif
+}
+
+/**
+ * \brief Wakes all workers and waits for them to finish the tasks.
+ *
+ * This function is called by the controller thread.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_signal(xbt_parmap_t parmap)
+{
+#ifdef HAVE_FUTEX_H
+ int myflag = parmap->done;
+ parmap->thread_counter = 0;
+ parmap->work++;
+
+ /* wake all workers */
+ futex_wake(&parmap->work, parmap->num_workers);
+
+ if (parmap->status == PARMAP_WORK) {
+ /* also work myself */
+ void* work = xbt_parmap_next(parmap);
+ if (work != NULL) {
+ parmap->fun(work);
+ }
+ }
+
+ unsigned int mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
+ if (mycount < parmap->num_workers) {
+ /* some workers have not finished yet */
+ futex_wait(&parmap->done, myflag);
+ }
+
+#endif
+}
+
+/**
+ * \brief Waits for some work to process.
+ *
+ * This function is called by each worker when it has no more work to do.
+ *
+ * \param parmap a parmap
+ */
+static void xbt_parmap_wait(xbt_parmap_t parmap)
+{
+#ifdef HAVE_FUTEX_H
+ int myflag;
+ unsigned int mycount;
+
+ myflag = parmap->work;
+ mycount = __sync_add_and_fetch(&parmap->thread_counter, 1);
+ if (mycount == parmap->num_workers) {
+ /* all workers have finished, wake the controller */
+ parmap->done++;
+ futex_wake(&parmap->done, 1);
+ }
+
+ /* wait for more work */
+ futex_wait(&parmap->work, myflag);
+#endif