findコマンドが遅いからgoで書き直してみた件 ref: http://qiita.com/A_Resas/items/aa22af6df3c8b6a89409

file0.txt

$ sudo time find / -name "*client*" > /dev/null

real    0m1.503s
user    0m0.980s
sys     0m1.068s

file1.go

package main

import (
    "fmt"
    "io/ioutil"
    "path/filepath"
    "strings"
)

func main() {
    fmt.Println(dirwalk("/"))
}

func dirwalk(dir string) []string {
    files, err := ioutil.ReadDir(dir)
    if err != nil {
        fmt.Println(err)
    }

    var paths []string
    for _, file := range files {
        if file.IsDir() {
            paths = append(paths, dirwalk(filepath.Join(dir, file.Name()))...)
            continue
        }
        if strings.Contains(file.Name(), "README"){
        paths = append(paths, filepath.Join(dir, file.Name()))
        }
    }

    return paths
}

file2.txt

#普通のfind
$ time find / -name "*README*" 

real    0m1.273s
user    0m0.516s
sys     0m0.680s

#goで書いたfind
$ time ./cmd

real    0m2.167s
user    0m1.000s
sys     0m1.184s

file5.txt

#普通のfind
$ time find / -name "*README*" | wc -l
3354

real    0m1.273s
user    0m0.516s
sys     0m0.680s

#goで書いたfind
$ time ./cmd / README | wc -l
3361

real    0m1.648s
user    0m0.952s
sys     0m1.240s

file6.txt

#普通のfind
$ time find / -name "*README*" | wc -l
416

real    0m0.921s
user    0m0.236s
sys     0m0.308s

#goで書いたfind
$ time ./cmd / README | wc -l
419

real    0m0.595s
user    0m0.572s
sys     0m0.536s

file7.txt

#普通のfind
0時58分14秒  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
10時58分15秒  all    5.53    0.00    9.55    0.00    0.00    0.17    0.00    0.00    0.00   84.76
10時58分15秒    0    3.03    0.00   10.10    0.00    0.00    1.01    0.00    0.00    0.00   85.86
10時58分15秒    1   14.85    0.00   27.72    0.00    0.00    0.99    0.00    0.00    0.00   56.44
10時58分15秒    2   15.46    0.00   18.56    0.00    0.00    0.00    0.00    0.00    0.00   65.98
10時58分15秒    3    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00
10時58分15秒    4    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00
10時58分15秒    5    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00    0.00  100.00

#goで書いたfind
10時58分42秒  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
10時58分43秒  all   10.89    0.00   15.58    0.00    0.00    0.00    0.00    0.00    0.00   73.53
10時58分43秒    0   12.00    0.00   14.00    0.00    0.00    0.00    0.00    0.00    0.00   74.00
10時58分43秒    1   10.00    0.00   16.00    0.00    0.00    0.00    0.00    0.00    0.00   74.00
10時58分43秒    2   12.00    0.00   17.00    0.00    0.00    0.00    0.00    0.00    0.00   71.00
10時58分43秒    3    9.00    0.00   14.00    0.00    0.00    0.00    0.00    0.00    0.00   77.00
10時58分43秒    4   10.42    0.00   13.54    0.00    0.00    0.00    0.00    0.00    0.00   76.04
10時58分43秒    5   11.88    0.00   18.81    0.00    0.00    0.00    0.00    0.00    0.00   69.31

fingp.gp

package fingo

import (
    "fmt"
    "io/ioutil"
    "os"
    "path/filepath"
    "runtime"
    "strings"
    "sync"
    "unsafe"
)

func para(root, word string, d os.FileInfo, buff *[]byte, wg *sync.WaitGroup) {
    *buff = append(*buff, dirwalk(word, filepath.Join(root, d.Name()))...)
    defer wg.Done()
}

func FindFile(root, word string) string {
    dir, err := ioutil.ReadDir(root)
    if err != nil {
        fmt.Println(err)
    }

    runtime.GOMAXPROCS(runtime.NumCPU())
    wg := new(sync.WaitGroup)
    buff := make([]byte, 0, 1000)

    for _, d := range dir {
        if !d.IsDir() {
            dirwalk(word, filepath.Join(root, d.Name()))
            continue
        }
        wg.Add(1)
        go para(root, word, d, &buff, wg)
    }
    wg.Wait()
    return string(buff)
}


func dirwalk(word, dir string) []byte {
    files, err := ioutil.ReadDir(dir)
    if err != nil {
        fmt.Println(err)
    }

    paths := make([]byte, 0, 200)

    for _, file := range files {
        if file.IsDir() {
            paths = append(paths, dirwalk(word, filepath.Join(dir, file.Name()))...)
            continue
        }
        if strings.Contains(file.Name(), word) {
            path := filepath.Join(dir, file.Name()) + "\n"
            bp := *(*[]byte)(unsafe.Pointer(&path))
            paths = append(paths, bp...)
        }
    }
    return paths
}

main.go

package main

import (
    "fmt"
    "github.com/nao4arale/fingo"
    "os"
    "runtime"
)

func main() {
  /* os.Args[1]...Dirctory, os.Args[2]...To find Words. */
    fmt.Printf("%s", fingo.FindFile(os.Args[1], os.Args[2]))
}