文章目录
GoLang之使用原子操作
注:本文基于Windos系统上Go SDK v1.8进行
1.原子操作性能比较
package main
import (
"fmt"
"sync"
"time"
)
type Counter interface {
Inc()
Load() int64
}
// 普通版
type CommonCounter struct {
counter int64
}
func (c CommonCounter) Inc() {
c.counter++
}
func (c CommonCounter) Load() int64 {
return c.counter
}
func test(c Counter) {
var wg sync.WaitGroup
start := time.Now()
for i := 0; i < 1000; i++ {
wg.Add(1)
go func() {
c.Inc()
wg.Done()
}()
}
wg.Wait()
end := time.Now()
fmt.Println(c.Load(), end.Sub(start))
}
func main() {
c1 := CommonCounter{} // 非并发安全
test(c1)//输出:0 2.0248ms
}
package main
import (
"fmt"
"sync"
"time"
)
type Counter interface {
Inc()
Load() int64
}
// 普通版
type CommonCounter struct {
counter int64
}
func (c *CommonCounter) Inc() {
c.counter++
}
func (c *CommonCounter) Load() int64 {
return c.counter
}
func test(c Counter) {
var wg sync.WaitGroup
start := time.Now()
for i := 0; i < 1000; i++ {
wg.Add(1)
go func() {
c.Inc()
wg.Done()
}()
}
wg.Wait()
end := time.Now()
fmt.Println(c.Load(), end.Sub(start))
}
func main() {
c1 := CommonCounter{} // 非并发安全
test(&c1)
/*
第一次运行输出:991 1.9983ms
第二次运行输出:984 2.4997ms
*/
}
互斥锁版
package main
import (
"fmt"
"sync"
"time"
)
type Counter interface {
Inc()
Load() int64
}
// 互斥锁版
type MutexCounter struct {
counter int64
lock sync.Mutex
}
func (m *MutexCounter) Inc() {
m.lock.Lock()
defer m.lock.Unlock()
m.counter++
}
func (m *MutexCounter) Load() int64 {
m.lock.Lock()
defer m.lock.Unlock()
return m.counter
}
func test(c Counter) {
var wg sync.WaitGroup
start := time.Now()
for i := 0; i < 1000; i++ {
wg.Add(1)
go func() {
c.Inc()
wg.Done()
}()
}
wg.Wait()
end := time.Now()
fmt.Println(c.Load(), end.Sub(start))
}
func main() {
c2 := MutexCounter{} // 使用互斥锁实现并发安全
test(&c2)//输出:1000 2.0023ms
}
原子操作版
package main
import (
"fmt"
"sync"
"sync/atomic"
"time"
)
type Counter interface {
Inc()
Load() int64
}
// 原子操作版
type AtomicCounter struct {
counter int64
}
func (a *AtomicCounter) Inc() {
atomic.AddInt64(&a.counter, 1)
}
func (a *AtomicCounter) Load() int64 {
return atomic.LoadInt64(&a.counter)
}
func test(c Counter) {
var wg sync.WaitGroup
start := time.Now()
for i := 0; i < 1000; i++ {
wg.Add(1)
go func() {
c.Inc()
wg.Done()
}()
}
wg.Wait()
end := time.Now()
fmt.Println(c.Load(), end.Sub(start))
}
func main() {
c3 := AtomicCounter{} // 并发安全且比互斥锁效率更高
test(&c3)
//输出:1000 2.0003ms
}