[go]递归函数中的多重读取速度较慢

var m sync.Mutex

func recurseDirectoriesMultiThread(wg *sync.WaitGroup, photoPaths *[]string, directory string) {
    defer wg.Done()
    items, _ := os.ReadDir(directory)
    for _, item := range items {
        if item.IsDir() {
            wg.Add(1)
            go recurseDirectoriesMultiThread(wg, photoPaths, directory+"/"+item.Name())
        } else {
            // handle file
            m.Lock()
            *photoPaths = append(*photoPaths, directory+"/"+item.Name())
            m.Unlock()
        }
    }

}
func recurseDirectories(photoPaths *[]string, directory string) {
    items, _ := os.ReadDir(directory)
    for _, item := range items {
        if item.IsDir() {
            recurseDirectories(photoPaths, directory+"/"+item.Name())
        } else {
            // handle file
            *photoPaths = append(*photoPaths, directory+"/"+item.Name())
        }
    }
}

func main() {
    args := os.Args
    fmt.Println(args[1])
    path := args[1]

    stringSlice1 := make([]string, 0) // slice
    start := time.Now()
    recurseDirectories(&stringSlice1, path)
    fmt.Println("Single thread time " + time.Since(start).String())
    fmt.Println("Number of files " + strconv.Itoa(len(stringSlice1)))

    stringSlice2 := make([]string, 0) // slice
    wg := new(sync.WaitGroup)
    wg.Add(1)
    start = time.Now()
    recurseDirectoriesMultiThread(wg, &stringSlice2, path)
    wg.Wait()
    fmt.Println("Mulit thread time " + time.Since(start).String())
    fmt.Println("Number of files " + strconv.Itoa(len(stringSlice2)))
}

Mulit thread time 224.196833ms
Number of files 3123
Single thread time 147.0

Mulit thread time 228.218042ms
Number of files 3123
Single thread time 149.666041ms
Number of files 3123

Mulit thread time 185.23275ms
Number of files 3123
Single thread time 147.412958ms
Number of files 3123