Using Golang's synchronization technology to achieve high-performance concurrency

Using Golang's synchronization technology to achieve high-performance concurrency

Abstract:
Golang is a very powerful programming language in terms of concurrency processing, which uses built-in Synchronization primitives and efficient coroutine mechanisms make it relatively easy to write high-performance concurrent programs. This article will introduce common synchronization technologies in Golang, including mutex locks, condition variables, read-write locks and atomic operations, and give specific code examples.

Introduction:
In today's information age, most applications need to handle a large number of concurrent requests. In order to ensure the correctness and performance of the program, it is crucial to handle concurrency properly. As a concurrency-friendly programming language, Golang provides some very useful synchronization technologies that can help us implement high-performance concurrent programs.

1. Mutex lock
Mutex lock is the most basic synchronization technology, which can help us achieve mutually exclusive access to shared variables. In Golang, we can use the built-in sync package to implement mutex locks. Here is a simple example:

package main

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

var counter = 0
var mutex sync.Mutex

func increment() {
    mutex.Lock()
    counter++
    mutex.Unlock()
}

func main() {
    for i := 0; i < 1000; i++ {
        go increment()
    }

    time.Sleep(time.Second)

    fmt.Println("counter:", counter)
}

In the above code, we use a mutex lock mutex to protect access to the shared variable counter. In the increment function, we first call the Lock method to obtain the mutex lock, then perform an increment operation on counter, and finally use Unlock Method releases the mutex lock. In the main function, we start 1000 goroutines to perform increment operations on counter at the same time, and finally output the value of counter.

2. Condition variables
Condition variables are a synchronization mechanism that allows goroutine to wait or wake up. In Golang, we can use the built-in sync package to implement condition variables. The following is a simple example:

package main

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

var (
    counter = 0
    cond    = sync.NewCond(&sync.Mutex{})
)

func increment() {
    cond.L.Lock()
    counter++
    cond.Signal()
    cond.L.Unlock()
}

func decrement() {
    cond.L.Lock()
    for counter == 0 {
        cond.Wait()
    }
    counter--
    cond.L.Unlock()
}

func main() {
    for i := 0; i < 1000; i++ {
        go increment()
        go decrement()
    }

    time.Sleep(time.Second)

    fmt.Println("counter:", counter)
}

In the above code, we use a condition variable cond and a mutex lock mutex to implement shared variables# Secure access to ##counter. In the increment function, we first obtain the mutex lock, then perform an increment operation on counter, and finally call the Signal method to wake up a signal waiting in cond goroutine on . In the decrement function, we first obtain the mutex lock, and then check whether the value of counter is 0. If so, call the Wait method to wait until it is awakened. , and then perform a self-decrement operation on counter. In the main function, we start 1000 increment and decrement functions at the same time, and finally output the value of counter.

Read-write lock is a synchronization mechanism that allows multiple goroutines to concurrently read shared resources, but only allows a single goroutine to write to shared resources. In Golang, we can use the built-in sync package to implement read-write locks. Here is a simple example:

package main

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

var (
    counter = 0
    rwLock  = sync.RWMutex{}
)

func read() {
    rwLock.RLock()
    fmt.Println("counter:", counter)
    time.Sleep(time.Millisecond)
    rwLock.RUnlock()
}

func write() {
    rwLock.Lock()
    counter++
    time.Sleep(time.Millisecond)
    rwLock.Unlock()
}

func main() {
    for i := 0; i < 10; i++ {
        go read()
        go write()
    }

    time.Sleep(time.Second)
}

rwLock to protect access to the shared variable counter. In the read function, we use the RLock method to obtain the read lock, then output the value of counter, and call the RUnlock method to release the read lock . In the write function, we use the Lock method to obtain the write lock, then increment the counter, and call the Unlock method to release it Write lock. In the main function, we start 10 read and write functions at the same time.

Atomic operation is a synchronization mechanism that can realize atomic operations on shared variables without a mutex lock. In Golang, we can use the built-in atomic package to implement atomic operations. Here is a simple example:

package main

import (
    "fmt"
    "sync/atomic"
    "time"
)

var counter int32

func increment() {
    atomic.AddInt32(&counter, 1)
}

func main() {
    for i := 0; i < 1000; i++ {
        go increment()
    }

    time.Sleep(time.Second)

    fmt.Println("counter:", atomic.LoadInt32(&counter))
}

AddInt32 function to perform an atomic increment operation on the shared variable counter, and use ## The #LoadInt32 function obtains the value of counter. In the main function, we start 1000 increment functions at the same time, and finally output the value of counter. Conclusion:

References:

• Go official website (https://golang.org/)

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