Highly concurrent programming and resource competition in Go language

With the rapid development of the Internet and mobile Internet, more and more applications need to handle highly concurrent requests. How to handle these requests efficiently has become a challenge for developers. Go language has become the language of choice in high-concurrency scenarios because of its efficient concurrency processing mechanism and easy-to-use language features. This article will introduce knowledge related to high-concurrency programming and resource competition in the Go language.

1. Concurrent programming in Go language

Concurrent programming in Go language is implemented through goroutine. Goroutine is a lightweight thread that can run on a small stack. It is started and destroyed quickly. It can run thousands of goroutines at the same time to achieve high concurrency. The following is a simple goroutine example:

func main() {
    go func() {
        // goroutine逻辑
    }()
}

Another very important feature of concurrent programming in Go language is channel, which is a bridge for communication between goroutines. Channel is a thread-safe queue that supports synchronization and mutual exclusion between different goroutines. A simple channel implementation is as follows:

func main() {
    ch := make(chan int)
    go func() {
        // goroutine逻辑
        ch <- 1
    }()
    <-ch
}

In the above code, a channel ch is first created, then a goroutine is started, some logic is executed in it, and the result is sent to the channel through ch, and finally the main function Wait for the goroutine to finish executing through the receive operation (<-ch) before ending.

2. Resource competition

In a multi-threaded environment, resource competition is a common problem. In the Go language, accessing shared variables may cause resource contention because multiple goroutines may access the same shared variable at the same time, leading to unpredictable results.

The following is a simple demonstration code:

func main() {
    var count int
    for i := 0; i < 10000; i++ {
        go func() {
            count++
        }()
    }
    fmt.Println("count:", count)
}

In the above code, 10,000 goroutines are started, and each goroutine will add one to the shared variable count. However, since the execution order of goroutines is uncertain, the final result is also uncertain. In the local test, sometimes the count result is 9996, sometimes it is 9998, and sometimes it is 10000.

In order to avoid this situation, we need to use the lock mechanism provided in the Go language to lock and unlock shared variables to ensure that only one goroutine can operate the shared variables at the same time. The following is an improved sample code:

func main() {
    var count int
    mu := sync.Mutex{}
    for i := 0; i < 10000; i++ {
        go func() {
            mu.Lock()
            count++
            mu.Unlock()
        }()
    }
    time.Sleep(time.Second) // 等待goroutine执行完毕
    fmt.Println("count:", count)
}

In the above code, we use the Mutex type provided by the sync package to lock (mu.Lock()) and unlock (mu. Unlock()) operation to ensure that only one goroutine can operate on shared variables at the same time. In order to ensure that all goroutines are executed, here we wait for 1 second through the Sleep function provided by the time package.

3. Precautions for high-concurrency programming

In high-concurrency programming, you need to pay attention to the following matters:

1. Avoid using shared resources such as global variables, Try to use private resources such as local variables.
2. Use the mutex lock mechanism to ensure that access to shared resources will not cause competition.
3. Try to use finer-grained lock mechanisms such as read-write locks and avoid using coarse-grained lock mechanisms to improve concurrency performance.
4. Use synchronization mechanisms such as channels to ensure correct coordination between goroutines.
5. Avoid creating too many goroutines, reduce goroutine overhead as much as possible, and improve system responsiveness and throughput.

4. Conclusion

The Go language has gradually become the language of choice in high-concurrency scenarios due to its efficient concurrency processing mechanism and simple and easy-to-use language features. In high-concurrency programming, you need to pay attention to resource competition issues, and ensure the correct coordination between multiple goroutines through the mutex lock mechanism and synchronization mechanism. At the same time, it is necessary to avoid creating too many goroutines and improve the system's responsiveness and throughput as much as possible to meet growing business needs.

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