diff --git a/upload-pack.c b/upload-pack.c
index c2643c0295..f8ba245616 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -270,6 +270,13 @@ static int relay_pack_data(int pack_objects_out, struct output_state *os,
 		}
 	}
 
+	/*
+	 * Make sure that we buffer some data before sending it to the client.
+	 * This significantly reduces the number of write(3p) syscalls.
+	 */
+	if (readsz && os->used < (LARGE_PACKET_DATA_MAX * 2 / 3))
+		return readsz;
+
 	if (os->used > 1) {
 		send_client_data(1, os->buffer, os->used - 1, use_sideband);
 		os->buffer[0] = os->buffer[os->used - 1];