diff --git a/driver/driver.go b/driver/driver.go
index b5d307d..2938644 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -22,7 +22,6 @@
 	"path/filepath"
 	"runtime"
 	"runtime/pprof"
-	"runtime/trace"
 	"sort"
 	"strings"
 	"sync"
@@ -39,7 +38,6 @@
 	affinity  = flag.Int("affinity", 0, "process affinity (passed to an OS-specific function like sched_setaffinity/SetProcessAffinityMask)")
 	tmpDir    = flag.String("tmpdir", os.TempDir(), "dir for temporary files")
 	genSvg    = flag.Bool("svg", false, "generate svg profiles")
-	traceFile = flag.String("trace", "", "write an execution trace to the named file after execution")
 
 	BenchNum  int
 	BenchMem  int
@@ -47,6 +45,12 @@
 	WorkDir   string
 
 	benchmarks = make(map[string]func() Result)
+
+	// startTrace starts runtime tracing if supported and
+	// requested and returns a function to stop tracing.
+	startTrace = func() func() {
+		return func() {}
+	}
 )
 
 func Register(name string, f func() Result) {
@@ -82,19 +86,8 @@
 		return
 	}
 
-	if *traceFile != "" {
-		f, err := os.Create(*traceFile)
-		if err != nil {
-			fmt.Fprintln(os.Stderr, err)
-			os.Exit(1)
-		}
-		defer f.Close()
-		if err := trace.Start(f); err != nil {
-			fmt.Fprintf(os.Stderr, "can't start tracing: %s\n", err)
-			os.Exit(1)
-		}
-		defer trace.Stop()
-	}
+	stopTrace := startTrace()
+	defer stopTrace()
 
 	res := f()
 
diff --git a/driver/driver_go15.go b/driver/driver_go15.go
new file mode 100644
index 0000000..f6cd9ca
--- /dev/null
+++ b/driver/driver_go15.go
@@ -0,0 +1,41 @@
+// Copyright 2015 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.
+
+// +build go1.5
+
+package driver
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"runtime/trace"
+)
+
+var traceFile = flag.String("trace", "", "write an execution trace to the named file after execution")
+
+func startTraceGo15() func() {
+	// New runtime tracing added in Go 1.5.
+	if *traceFile != "" {
+		f, err := os.Create(*traceFile)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		if err := trace.Start(f); err != nil {
+			fmt.Fprintf(os.Stderr, "can't start tracing: %s\n", err)
+			os.Exit(1)
+		}
+
+		return func() {
+			trace.Stop()
+			f.Close()
+		}
+	}
+	return func() {}
+}
+
+func init() {
+	startTrace = startTraceGo15
+}