github.com/runnerdave/go-benchmarking-example

Go Benchmarking example

simple benchmarking of string concatenation functions taken from: https://www.soroushjp.com/2015/01/27/beautifully-simple-benchmarking-with-go/

jimenezd-JSS1129:benchmarking-example jimenezd$ go test -bench=.
goos: darwin
goarch: amd64
pkg: github.com/runnerdave/benchmarking-example
BenchmarkSelfConcatOperator1000-12                  5000            272766 ns/op
BenchmarkSelfConcatBuffer1000-12                  200000              7214 ns/op
BenchmarkSelfConcatOperator100000-12                   1        1463489675 ns/op
BenchmarkSelfConcatBuffer100000-12                  2000            636606 ns/op
PASS
ok      github.com/runnerdave/benchmarking-example      5.728s

From the official Golang documentation: https://golang.org/pkg/testing/#hdr-Benchmarks

The benchmark function must run the target code b.N times. During benchmark execution, b.N is adjusted until the benchmark function lasts long enough to be timed reliably. The output

BenchmarkHello    10000000    282 ns/op

means that the loop ran 10000000 times at a speed of 282 ns per loop.

If a benchmark needs some expensive setup before running, the timer may be reset:

func BenchmarkBigLen(b *testing.B) {
    big := NewBig()
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        big.Len()
    }
}

If a benchmark needs to test performance in a parallel setting, it may use the RunParallel helper function; such benchmarks are intended to be used with the go test -cpu flag:

func BenchmarkTemplateParallel(b *testing.B) {
    templ := template.Must(template.New("test").Parse("Hello, {{.}}!"))
    b.RunParallel(func(pb *testing.PB) {
        var buf bytes.Buffer
        for pb.Next() {
            buf.Reset()
            templ.Execute(&buf, "World")
        }
    })
}