diff --git a/labels/labels_test.go b/labels/labels_test.go
index 709568288b..200c1fc2a5 100644
--- a/labels/labels_test.go
+++ b/labels/labels_test.go
@@ -87,7 +87,7 @@ func TestCompareAndEquals(t *testing.T) {
 }
 
 func BenchmarkSliceSort(b *testing.B) {
-	lbls, err := ReadLabels("../testdata/1m.series", 900000)
+	lbls, err := ReadLabels("../testdata/20kseries.json", 20000)
 	testutil.Ok(b, err)
 
 	for len(lbls) < 20e6 {