Atomic Counters {.en}

原子计数器 {.zh}

::: {.en} The primary mechanism for managing state in Go is communication over channels. We saw this for example with worker pools. There are a few other options for managing state though. Here we’ll look at using the sync/atomic package for atomic counters accessed by multiple goroutines. :::

::: {.zh}

Go中管理状态的主要机制是通过渠道进行通信。我们在[工作池]（工作池）中看到了这一点。但是，有一些其他选项用于管理州。这里我们将看到使用多个goroutines访问的atomiccounters的sync / atomic包。

:::

package main
import "fmt"
import "time"
import "sync/atomic"
func main() {

::: {.en} We’ll use an unsigned integer to represent our (always-positive) counter. :::

::: {.zh}

我们将使用无符号整数来表示我们的（始终为正）计数器。

:::

    var ops uint64

::: {.en} To simulate concurrent updates, we’ll start 50 goroutines that each increment the counter about once a millisecond. :::

::: {.zh}

为了模拟并发更新，我们将启动50goroutines，每个增加计数器大约一毫秒。

:::

    for i := 0; i < 50; i++ {
        go func() {
            for {

::: {.en} To atomically increment the counter we use AddUint64, giving it the memory address of our ops counter with the & syntax. :::

::: {.zh}

为了原子地递增计数器，我们使用AddUint64，给它带有＆语法的ops计数器的memoryaddress。

:::

                atomic.AddUint64(&ops, 1)

::: {.en} Wait a bit between increments. :::

::: {.zh}

在增量之间稍等一下。

:::

                time.Sleep(time.Millisecond)
            }
        }()
    }

::: {.en} Wait a second to allow some ops to accumulate. :::

::: {.zh}

等一下，允许一些操作积累。

:::

    time.Sleep(time.Second)

::: {.en} In order to safely use the counter while it’s still being updated by other goroutines, we extract a copy of the current value into opsFinal via LoadUint64. As above we need to give this function the memory address &ops from which to fetch the value. :::

::: {.zh}

为了安全地使用计数器，当它仍然由其他goroutine更新时，我们通过LOadUint64将当前值的副本提取到“opsFinal”。如上所述，我们需要给这个函数提供内存地址＆ops，从中获取值。

:::

    opsFinal := atomic.LoadUint64(&ops)
    fmt.Println("ops:", opsFinal)
}

::: {.en} Running the program shows that we executed about 40,000 operations. :::

::: {.zh}

运行该程序表明我们执行了约40,000次操作。

:::

$ go run atomic-counters.go
ops: 41419

::: {.en} Next we’ll look at mutexes, another tool for managing state. :::

::: {.zh}

接下来我们将介绍互斥体，这是另一个管理状态的工具。

:::

go by example 中文文档

Atomic Counters - 原子计数器

Atomic Counters {.en}

原子计数器 {.zh}