diff --git a/test/benchmark-async-pummel.c b/test/benchmark-async-pummel.c
index a4eb48ca..2f318967 100644
--- a/test/benchmark-async-pummel.c
+++ b/test/benchmark-async-pummel.c
@@ -86,7 +86,8 @@ static int test_async_pummel(int nthreads) {
   for (i = 0; i < nthreads; i++)
     ASSERT(0 == uv_thread_join(tids + i));
 
-  printf("%s callbacks in %.2f seconds (%s/sec)\n",
+  printf("async_pummel_%d: %s callbacks in %.2f seconds (%s/sec)\n",
+         nthreads,
          fmt(callbacks),
          time / 1e9,
          fmt(callbacks / (time / 1e9)));
diff --git a/test/benchmark-async.c b/test/benchmark-async.c
index 649b1c5b..7d37ab41 100644
--- a/test/benchmark-async.c
+++ b/test/benchmark-async.c
@@ -107,7 +107,8 @@ static int test_async(int nthreads) {
     ASSERT(ctx->main_seen == (unsigned int) NUM_PINGS);
   }
 
-  printf("%.2f sec (%s/sec)\n",
+  printf("async%d: %.2f sec (%s/sec)\n",
+         nthreads,
          time / 1e9,
          fmt(NUM_PINGS / (time / 1e9)));