Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

1.7.4
go version devel +78860b2ad

What operating system and processor architecture are you using (go env)?

GOARCH="amd64"
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build805050938=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
CGO_ENABLED="1"
PKG_CONFIG="pkg-config"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"

What did you do?

I run program normal way, not "go test". I call testing.Benchmark() in code. Benchmark function call Run() method to execute sub benchmark.

func main() {
    result := testing.Benchmark(func(parentB *testing.B) {
        parentB.Run("example", func(b *testing.B) {
            for n := 0; n < b.N; n++ {
                println("ok")
            }
        })
    })
    println(result.String())
}

Behaviour already reproduced prooflink http://stackoverflow.com/questions/41861918/using-testing-benchmark-does-not-produce-any-output

What did you expect to see?

According to the documentation I expect

Benchmark benchmarks a single function. Useful for creating custom benchmarks that do not use the "go test" command.

If f calls Run, the result will be an estimate of running all its subbenchmarks that don't call Run in sequence in a single benchmark.

What did you see instead?

Sub benchmark run N times(no once) but result is
0 0 ns/op