1 files changed, 45 insertions, 14 deletions

diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 1bcee23ca1..60141196df 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1582,27 +1582,42 @@ struct thread_params {
 	unsigned *processed;
 };
 
+static pthread_mutex_t data_request  = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t data_ready    = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t data_provider = PTHREAD_MUTEX_INITIALIZER;
+static struct thread_params *data_requester;
+
 static void *threaded_find_deltas(void *arg)
 {
-	struct thread_params *p = arg;
-	if (p->list_size)
-		find_deltas(p->list, p->list_size,
-			    p->window, p->depth, p->processed);
-	return NULL;
+	struct thread_params *me = arg;
+
+	for (;;) {
+		pthread_mutex_lock(&data_request);
+		data_requester = me;
+		pthread_mutex_unlock(&data_provider);
+		pthread_mutex_lock(&data_ready);
+
+		if (!me->list_size)
+			return NULL;
+
+		find_deltas(me->list, me->list_size,
+			    me->window, me->depth, me->processed);
+	}
 }
 
-#define NR_THREADS	8
+#define NR_THREADS	4
 
 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 			   int window, int depth, unsigned *processed)
 {
 	struct thread_params p[NR_THREADS];
 	int i, ret;
+	unsigned chunk_size;
+
+	pthread_mutex_lock(&data_provider);
+	pthread_mutex_lock(&data_ready);
 
 	for (i = 0; i < NR_THREADS; i++) {
-		unsigned sublist_size = list_size / (NR_THREADS - i);
-		p[i].list = list;
-		p[i].list_size = sublist_size;
 		p[i].window = window;
 		p[i].depth = depth;
 		p[i].processed = processed;
@@ -1610,13 +1625,29 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 				     threaded_find_deltas, &p[i]);
 		if (ret)
 			die("unable to create thread: %s", strerror(ret));
-		list += sublist_size;
-		list_size -= sublist_size;
 	}
 
-	for (i = 0; i < NR_THREADS; i++) {
-		pthread_join(p[i].thread, NULL);
-	}
+	/* this should be auto-tuned somehow */
+	chunk_size = window * 1000;
+
+	do {
+		unsigned sublist_size = chunk_size;
+		if (sublist_size > list_size)
+			sublist_size = list_size;
+
+		pthread_mutex_lock(&data_provider);
+		data_requester->list = list;
+		data_requester->list_size = sublist_size;
+		pthread_mutex_unlock(&data_ready);
+
+		list += sublist_size;
+		list_size -= sublist_size;
+		if (!sublist_size) {
+			pthread_join(data_requester->thread, NULL);
+			i--;
+		}
+		pthread_mutex_unlock(&data_request);
+	} while (i);
 }
 
 #else