diff --git a/stream/stream_bench_test.go b/stream/stream_bench_test.go
new file mode 100644
index 0000000..ff570b9
--- /dev/null
+++ b/stream/stream_bench_test.go
@@ -0,0 +1,27 @@
+package stream_test
+
+import (
+	"testing"
+
+	"github.com/primetalk/goio/io"
+	"github.com/primetalk/goio/slice"
+	"github.com/primetalk/goio/stream"
+	"github.com/stretchr/testify/assert"
+)
+
+func BenchmarkStreamSum(b *testing.B) {
+	sumIO := stream.Head(stream.Sum(stream.Take(nats, 10000)))
+	res, err1 := io.UnsafeRunSync(sumIO)
+	assert.NoError(b, err1)
+	assert.Equal(b, 50005000, res)
+}
+
+var range10000 = func() (res []int) {
+	res, _ = io.UnsafeRunSync(stream.ToSlice(stream.Take(nats, 10000)))
+	return
+}()
+
+func BenchmarkSliceSum(b *testing.B) {
+	res := slice.Sum(range10000)
+	assert.Equal(b, 50005000, res)
+}