Comparing performance

return error

• create file return.go

func newErr() error {
    return errors.new("this is error")
}
func fmtErr() error {
    return fmt.Errorf("this is error")
}

• create file return_test.go

func BenchmarkNewErr(b *testing.B) {
    for i := 0; i < b.N; i++ {
        newErr()
    }
}

func BenchmarkFmtErr(b *testing.B) {
    for i := 0; i < b.N; i++ {
        fmtErr()
    }
}

• run:

go test -bench=. -count=5

• Output:

goos: linux
goarch: amd64
cpu: Intel(R) Core(TM) i5-10505 CPU @ 3.20GHz
BenchmarkNewErr-12      1000000000               0.2478 ns/op
BenchmarkNewErr-12      1000000000               0.2260 ns/op
BenchmarkNewErr-12      1000000000               0.2342 ns/op
BenchmarkNewErr-12      1000000000               0.2352 ns/op
BenchmarkNewErr-12      1000000000               0.2287 ns/op
BenchmarkFmtErr-12      13758192               114.9 ns/op
BenchmarkFmtErr-12      13655595               102.3 ns/op
BenchmarkFmtErr-12      12359242                99.00 ns/op
BenchmarkFmtErr-12      13170003                86.94 ns/op
BenchmarkFmtErr-12      12656886                85.36 ns/op

-> errors.New() faster fmt.Errorf()

Convert Int to String

• create file convert.go

  func MethodInt(i int) string {
      return strconv.FormatInt(int64(i), 10)
  }
  func MethodItoa(i int) string {
      return strconv.Itoa(i)
  }
  func MethodFmt(i int) string {
      return fmt.Sprintf("%d", i)
  }
  

• create file convert_test.go, copy all below code.

  func BenchmarkFmt(b *testing.B) {
      // TODO: Initialize
      number := 10
      for i := 0; i < b.N; i++ {
          // TODO: Your Code Here
          MethodFmt(number)
      }
  }
  
  func BenchmarkMethodInt(b *testing.B) {
      // TODO: Initialize
      number := 10
      for i := 0; i < b.N; i++ {
          // TODO: Your Code Here
          MethodInt(number)
      }
  }
  func BenchmarkMethodItoa(b *testing.B) {
      // TODO: Initialize
      number := 10
      for i := 0; i < b.N; i++ {
          // TODO: Your Code Here
          MethodItoa(number)
      }
  }
  

• run:

  go test -bench-. -count=3
  

• output:

  goos: linux
  goarch: amd64
  cpu: Intel(R) Core(TM) i5-10505 CPU @ 3.20GHz
  BenchmarkFmt-12                 23235129                51.74 ns/op
  BenchmarkFmt-12                 23171469                51.51 ns/op
  BenchmarkFmt-12                 23137256                54.24 ns/op
  BenchmarkMethodInt-12           569711481                2.030 ns/op
  BenchmarkMethodInt-12           592133842                2.019 ns/op
  BenchmarkMethodInt-12           595410151                2.027 ns/op
  BenchmarkMethodItoa-12          595789161                2.020 ns/op
  BenchmarkMethodItoa-12          584260538                2.035 ns/op
  BenchmarkMethodItoa-12          487900248                2.076 ns/op
  

  -> function fmt.Sprintf is most slowly.