Merge tag 'upstream/1.4' into debian-experimental

* tag 'upstream/1.4':
  Imported Upstream version 1.4

1 files changed, 46 insertions, 0 deletions

diff --git a/src/runtime/norace_test.go b/src/runtime/norace_test.go
new file mode 100644
index 000000000..3b171877a
--- /dev/null
+++ b/src/runtime/norace_test.go
@@ -0,0 +1,46 @@
+// Copyright 2013 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.
+
+// The file contains tests that can not run under race detector for some reason.
+// +build !race
+
+package runtime_test
+
+import (
+	"runtime"
+	"testing"
+)
+
+// Syscall tests split stack between Entersyscall and Exitsyscall under race detector.
+func BenchmarkSyscall(b *testing.B) {
+	benchmarkSyscall(b, 0, 1)
+}
+
+func BenchmarkSyscallWork(b *testing.B) {
+	benchmarkSyscall(b, 100, 1)
+}
+
+func BenchmarkSyscallExcess(b *testing.B) {
+	benchmarkSyscall(b, 0, 4)
+}
+
+func BenchmarkSyscallExcessWork(b *testing.B) {
+	benchmarkSyscall(b, 100, 4)
+}
+
+func benchmarkSyscall(b *testing.B, work, excess int) {
+	b.SetParallelism(excess)
+	b.RunParallel(func(pb *testing.PB) {
+		foo := 42
+		for pb.Next() {
+			runtime.Entersyscall()
+			for i := 0; i < work; i++ {
+				foo *= 2
+				foo /= 2
+			}
+			runtime.Exitsyscall()
+		}
+		_ = foo
+	})
+}