1 files changed, 44 insertions, 0 deletions
diff --git a/libgo/go/context/benchmark_test.go b/libgo/go/context/benchmark_test.go
new file mode 100644
index 00000000000..b79232704eb
--- /dev/null
+++ b/libgo/go/context/benchmark_test.go
@@ -0,0 +1,44 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package context_test
+
+import (
+	. "context"
+	"fmt"
+	"testing"
+)
+
+func BenchmarkContextCancelTree(b *testing.B) {
+	depths := []int{1, 10, 100, 1000}
+	for _, d := range depths {
+		b.Run(fmt.Sprintf("depth=%d", d), func(b *testing.B) {
+			b.Run("Root=Background", func(b *testing.B) {
+				for i := 0; i < b.N; i++ {
+					buildContextTree(Background(), d)
+				}
+			})
+			b.Run("Root=OpenCanceler", func(b *testing.B) {
+				for i := 0; i < b.N; i++ {
+					ctx, cancel := WithCancel(Background())
+					buildContextTree(ctx, d)
+					cancel()
+				}
+			})
+			b.Run("Root=ClosedCanceler", func(b *testing.B) {
+				for i := 0; i < b.N; i++ {
+					ctx, cancel := WithCancel(Background())
+					cancel()
+					buildContextTree(ctx, d)
+				}
+			})
+		})
+	}
+}
+
+func buildContextTree(root Context, depth int) {
+	for d := 0; d < depth; d++ {
+		root, _ = WithCancel(root)
+	}
+}