Second commit

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 113 insertions, 0 deletions

diff --git a/barrier.c b/barrier.c
new file mode 100644
index 0000000..cd7bae8
--- /dev/null
+++ b/barrier.c
@@ -0,0 +1,113 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+void
+barrierwait(pthread_barrier_t *barrier)
+{
+#ifndef SINGLE_THREADED
+	int r = pthread_barrier_wait(barrier);
+	if (r && r != PTHREAD_BARRIER_SERIAL_THREAD) {
+		errno = r;
+		eprintf("pthread_barrier_wait:");
+	}
+#else
+	(void) barrier;
+#endif
+}
+
+
+void
+barriersend(struct barrier_group *group, struct global_data *global, void (*action)(struct algorithm *, struct global_data *))
+{
+	size_t index;
+	global->action = action;
+	if (group->nthreads)
+		barrierwait(&group->barrier);
+	for (index = 0; index < global->nalgorithms; index += group->nthreads + 1U)
+		(*action)(&global->algorithms[index], global);
+	if (group->nthreads)
+		barrierwait(&group->barrier);
+}
+
+
+#ifndef SINGLE_THREADED
+static void *
+slaveloop(void *thread_param)
+{
+	struct thread_data *data = thread_param;
+	void (*action)(struct algorithm *, struct global_data *);
+	size_t index;
+
+	for (;;) {
+		barrierwait(&data->group->barrier);
+		action = data->global->action;
+		if (!action)
+			break;
+		for (index = data->index; index < data->global->nalgorithms; index += data->group->nthreads + 1U)
+			(*action)(&data->global->algorithms[index], data->global);
+		barrierwait(&data->group->barrier);
+	}
+
+	return NULL;
+}
+#endif
+
+
+void
+createbarriergroup(struct barrier_group *group_out, size_t count, struct global_data *global)
+{
+#ifndef SINGLE_THREADED
+	size_t i;
+
+	group_out->nthreads = count - 1U;
+	group_out->threads = NULL;
+	if (!group_out->nthreads)
+		return;
+	group_out->threads = ecalloc(group_out->nthreads, sizeof(*group_out->threads));
+
+	if ((errno = pthread_barrier_init(&group_out->barrier, NULL, (unsigned)count)))
+		eprintf("pthread_barrier_init NULL %u:", (unsigned)count);
+
+	for (i = 0; i < group_out->nthreads; i++) {
+		group_out->threads[i].group = group_out;
+		group_out->threads[i].global = global;
+		group_out->threads[i].index = i + 1U;
+		errno = pthread_create(&group_out->threads[i].thread, NULL, &slaveloop, &group_out->threads[i]);
+		if (errno)
+			eprintf("pthread_create NULL:");
+	}
+#else
+	group_out->nthreads = 0U;
+	group_out->threads = NULL;
+	(void) global;
+	(void) count;
+#endif
+}
+
+
+void
+killbarriergroup(struct barrier_group *group, struct global_data *global)
+{
+#ifndef SINGLE_THREADED
+	size_t i;
+
+	if (!group->nthreads)
+		return;
+
+	global->action = NULL;
+	for (i = 0; i < group->nthreads; i++)
+		group->threads[i].global = global;
+	barrierwait(&group->barrier);
+
+	for (i = 0; i < group->nthreads; i++)
+		if ((errno = pthread_join(group->threads[i].thread, NULL)))
+			weprintf("pthread_join:");
+	pthread_barrier_destroy(&group->barrier);
+
+	free(group->threads);
+#else
+	(void) group;
+	(void) global;
+#endif
+}