入参为接口类型对函数执行效率的影响
const test_host = "https://filehelper.weixin.qq.com/"
func ImgUrl_interface(i interface{}) (string, []string) {
switch i.(type) {
default:
return "", nil
case string:
t := i.(string)
if t == "" {
return "", nil
}
return utils.ConcatStr(test_host, t), nil
case []string:
imgs := i.([]string)
ans := []string{}
for j := range imgs {
ans = append(ans, utils.ConcatStr(test_host, imgs[j]))
}
return "", ans
}
}
func ImgUrl_str(i string) string {
if i == "" {
return ""
}
return utils.ConcatStr(test_host, i)
}
func ImgUrl_slice(i []string) []string {
if i == nil {
return nil
}
ans := []string{}
for j := range i {
ans = append(ans, utils.ConcatStr(test_host, i[j]))
}
return ans
}
func BenchmarkImgUrl_interface(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ImgUrl_interface("a.png")
}
}
func BenchmarkImgUrl_str(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ImgUrl_str("a.png")
}
}
func BenchmarkImgUrl_interface_slice(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ImgUrl_interface([]string{"a.png", "b.png", "a1.png", "b1.png", "a2.png", "b2.png", "a3.png", "b3.png"})
}
}
func BenchmarkImgUrl_slice(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ImgUrl_slice([]string{"a.png", "b.png", "a1.png", "b1.png", "a2.png", "b2.png", "a3.png", "b3.png"})
}
}
func ConcatStr(l ...string) string {
b := strings.Builder{}
for i := range l {
b.WriteString(l[i])
}
return b.String()
}
go test -run=XXX -bench=.
goos: windows
goarch: amd64
pkg: WebSvc/internal/presentationLayer
cpu: Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
BenchmarkImgUrl_interface-12 25598641 47.23 ns/op
BenchmarkImgUrl_str-12 25240561 45.78 ns/op
BenchmarkImgUrl_interface_slice-12 1725375 737.5 ns/op
BenchmarkImgUrl_slice-12 1620464 700.1 ns/op
PASS
ok WebSvc/internal/presentationLayer 8.077s
Benchmark functions in Golang - Golang Docs https://golangdocs.com/benchmark-functions-in-golang
How to write benchmarks in Go | Dave Cheney https://dave.cheney.net/2013/06/30/how-to-write-benchmarks-in-go
import (
"bytes"
"strings"
)
func ConcatStrV0(l ...string) string {
var buf bytes.Buffer
for i := range l {
buf.WriteString(l[i])
}
// To build strings more efficiently, see the strings.Builder type.
// Go\src\bytes\buffer.go
return buf.String()
}
func ConcatStr(l ...string) string {
b := strings.Builder{}
for i := range l {
b.WriteString(l[i])
}
return b.String()
}
性能测试
func BenchmarkConcatStr(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ConcatStr([]string{"1", "a", ""}...)
}
}
func BenchmarkConcatStrV0(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ConcatStrV0([]string{"1", "a", ""}...)
}
}
var test_l = []string{"1", "a", "", "b := SelectBuilder{builder: &strings.Builder{}} b := SelectBuilder{builder: &strings.Builder{}} b := SelectBuilder{builder: &strings.Builder{}} b := SelectBuilder{builder: &strings.Builder{}} b := SelectBuilder{builder: &strings.Builder{}} b := SelectBuilder{builder: &strings.Builder{}}"}
func BenchmarkConcatStr_1(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ConcatStr(test_l...)
}
}
func BenchmarkConcatStrV0_1(b *testing.B) {
// run the function b.N times
for n := 0; n < b.N; n++ {
ConcatStrV0(test_l...)
}
}
go test -run=XXX -bench=.
goos: windows
goarch: amd64
pkg: WebSvc/utils
cpu: Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
BenchmarkConcatStr-12 34178004 30.38 ns/op
BenchmarkConcatStrV0-12 16447819 62.20 ns/op
BenchmarkConcatStr_1-12 9675211 110.0 ns/op
BenchmarkConcatStrV0_1-12 5310603 224.8 ns/op
PASS
ok WebSvc/utils 4.824s
小结：
1、
内存分配的基准测试
go test -run=^$ -bench=. bufio
% go test -run=XXX -bench=. -cpuprofile=c.p bytes
% go tool pprof c.p
基准测试
package main
type S [12]int64
var sX = make([]S, 1000)
var sY = make([]S, 1000)
var sZ = make([]S, 1000)
var sumX, sumY, sumZ int64
func Loop() {
sumX = 0
for j := 0; j < len(sX); j++ {
sumX += sX[j][0]
}
}
func Range_OneIterVar() {
sumY = 0
for j := range sY {
sumY += sY[j][0]
}
}
func Range_TwoIterVar() {
sumZ = 0
for _, v := range sZ {
sumZ += v[0]
}
}
package main
import "testing"
func Benchmark_Loop(b *testing.B) {
for i := 0; i < b.N; i++ {
sumX = 0
for j := 0; j < len(sX); j++ {
sumX += sX[j][0]
}
}
}
func Benchmark_Range_OneIterVar(b *testing.B) {
for i := 0; i < b.N; i++ {
sumY = 0
for j := range sY {
sumY += sY[j][0]
}
}
}
func Benchmark_Range_TwoIterVar(b *testing.B) {
for i := 0; i < b.N; i++ {
sumZ = 0
for _, v := range sZ {
sumZ += v[0]
}
}
}
Running tool: C:\Program Files\Go\bin\go.exe test -benchmem -run=^$ -coverprofile=C:\Users\XLE~1.FEN\AppData\Local\Temp\vscode-gos5y16I\go-code-cover -bench . A
goos: windows
goarch: amd64
pkg: A
cpu: Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
Benchmark_Loop-4 720507 1722 ns/op 0 B/op 0 allocs/op
Benchmark_Range_OneIterVar-4 725149 1843 ns/op 0 B/op 0 allocs/op
Benchmark_Range_TwoIterVar-4 300584 4271 ns/op 0 B/op 0 allocs/op
PASS
coverage: 0.0% of statements
ok A 4.179s
1. Go 性能调优之 —— 基准测试 - SegmentFault 思否 https://segmentfault.com/a/1190000016354758
