GoLang Channel与mutex的选择，性能差不多

go官方应该是更推荐使用chan

https://github.com/golang/go/wiki/MutexOrChannel

以下代码用于测试性能 — 不确保思路是正确的。

package main

import (
"fmt"
"sync"
"time"
)

type Op struct {
key int
val int
}

var lock sync.Mutex

var m1 map[int]int
var m2 map[int]int
var max int = 50000

func update_map_by_mutex(i int) {
lock.Lock()
m1[i] = i
if len(m1) == max {
fmt.Printf("%s mutex finish\n", time.Now())
}
lock.Unlock()
}

var ch chan Op

func update_map_by_chan(i int) {
ch <- Op{key: i, val: i}
}

func wait_for_chan(m map[int]int) {
for {
select {
case op := <-ch:
m[op.key] = op.val
if len(m2) == max {
fmt.Printf("%s chan finish\n", time.Now())
return
}
}
}
}

func main() {

m1 = make(map[int]int, max)
m2 = make(map[int]int, max)
ch = make(chan Op)
go wait_for_chan(m2)
for i := 0; i < max; i++ {
go update_map_by_chan(i)
go update_map_by_mutex(i)
}

time.Sleep(time.Second * 1)
}

输出结果：

2015-11-17 17:08:18.06992 +0800 CST mutex finish

2015-11-17 17:08:18.0709215 +0800 CST chan finish

mutex性能略好，但chan更go化，更推荐。