reference benchmark of goroutine ID parsing

Author: lainio

assert/goid_test.go

@@ -1,6 +1,8 @@
 package assert
 
 import (
+	"bytes"
+	"fmt"
 	"testing"
 )
 
@@ -15,6 +17,17 @@ func TestGoid(t *testing.T) {
 	}
 }
 
+func Test_oldGoid(t *testing.T) {
+	t.Parallel()
+	stackBytes := []byte(`goroutine 518 [running]:
+`)
+
+	id := oldGoid(stackBytes)
+	if id != 518 {
+		t.Fail()
+	}
+}
+
 func BenchmarkGoid(b *testing.B) {
 	_ = []byte(`goroutine 518 [running]:
 `)
@@ -32,3 +45,20 @@ func BenchmarkGoid_MyByteToInt(b *testing.B) {
 		_ = myByteToInt(stackBytes[10:])
 	}
 }
+
+func oldGoid(buf []byte) (id int) {
+	_, err := fmt.Fscanf(bytes.NewReader(buf), "goroutine %d", &id)
+	if err != nil {
+		panic("cannot get goroutine id: " + err.Error())
+	}
+	return id
+}
+
+func BenchmarkGoid_Old(b *testing.B) {
+	stackBytes := []byte(`goroutine 518 [running]:
+`)
+
+	for n := 0; n < b.N; n++ {
+		_ = oldGoid(stackBytes)
+	}
+}