$ go.dev test -c foo_test.go
$ ./foo.test -test.bench . -test.cpuprofile /tmp/cpu.out
$ go.dev tool pprof ./foo.test /tmp/cpu.out
(pprof) weblist # Stalls for several seconds... the output html file is 450MB

$ go1.6 test -c foo_test.go
$ ./foo.test -test.bench . -test.cpuprofile /tmp/cpu.out
$ go1.6 tool pprof ./foo.test /tmp/cpu.out
(pprof) weblist # Immediately launches browser with html file that is 209KB

package foo

import (
    "bufio"
    "io"
    "strings"
    "testing"
)

func BenchmarkFoo(b *testing.B) {
    s := strings.Repeat("Hello, world!", 100000)

    b.SetBytes(int64(len(s)))
    for i := 0; i < b.N; i++ {
        var r io.ByteReader
        r = bufio.NewReader(strings.NewReader(s))
        for {
            _, err := r.ReadByte()
            if err != nil {
                if err == io.EOF {
                    break
                }
                b.Fatal(err)
            }
        }
    }
}