PHP underlying thread pool and coroutine implementation methods

PHP underlying thread pool and coroutine implementation methods

In PHP programming, thread pools and coroutines are important methods to improve performance and concurrency capabilities. This article will introduce the underlying methods of implementing thread pools and coroutines in PHP, and provide specific code examples.

1. Implementation of thread pool

Thread pool is a mechanism for reusing threads, which can improve the performance of multi-threaded applications. In PHP, multi-threading can be used to execute multiple tasks concurrently and improve the concurrency capability of the program. The following is a simple PHP thread pool implementation example:

class ThreadPool
{
    private $pool;
    private $maxThreads;

    public function __construct($maxThreads)
    {
        $this->maxThreads = $maxThreads;
        $this->pool = new SplQueue();
    }

    public function run($task)
    {
        if(count($this->pool) < $this->maxThreads) {
            $thread = new Thread($task);
            $thread->start();
            $this->pool->enqueue($thread);
        } else {
            while(count($this->pool) >= $this->maxThreads) {
                usleep(1000);
            }
            $this->run($task); // 递归调用，直到有空闲线程
        }
    }

    public function wait()
    {
        while(!$this->pool->isEmpty()) {
            $thread = $this->pool->dequeue();
            $thread->join();
        }
    }
}

class Thread extends Thread {
    private $task;

    public function __construct($task) {
        $this->task = $task;
    }

    public function run() {
        // 执行任务
        call_user_func($this->task);
    }
}

// 示例
$pool = new ThreadPool(5);
for($i = 0; $i < 10; $i++) {
    $task = function() use($i) {
        echo "Task " . $i . " is running in thread " . Thread::getCurrentThreadId() . "
";
        usleep(1000000);
        echo "Task " . $i . " is completed
";
    };
    $pool->run($task);
}
$pool->wait();

In the above code, the thread pool ThreadPool class is used to maintain threads in the thread pool, and can run up to $maxThreads threads at the same time. The thread class Thread encapsulates specific tasks and uses the start method to start the thread to execute the task.

Run the sample code, you can see that the thread pool will run up to $maxThreads tasks at the same time, and after completing one task, the next task will be obtained for execution.

2. Implementation of coroutine

Coroutine is a lightweight thread that can pause and resume execution at different points in time. In PHP, highly scalable and concurrent applications can be achieved using coroutines. The following is a simple PHP coroutine implementation example:

function coroutine() {
    $task = (yield); // 获取第一个任务
    while($task) {
        call_user_func($task);
        $task = (yield); // 获取下一个任务
    }
}

// 示例
$coroutine = coroutine();
$coroutine->send(function() {
    echo "Task 1 is running
";
    usleep(1000000);
    echo "Task 1 is completed
";
});
$coroutine->send(function() {
    echo "Task 2 is running
";
    usleep(1000000);
    echo "Task 2 is completed
";
});

In the above code, the coroutine function defines a coroutine that pauses and resumes execution through the yield keyword. Call the send method to send tasks, and use functions to define specific tasks.

Run the sample code, you can see that the coroutine will execute the sent tasks in order, and continue to execute the next task after each task is completed.

Conclusion

The underlying thread pool and coroutine of PHP provide a high-performance and high-concurrency programming model. Through the thread pool, multiple threads can execute tasks concurrently and improve the concurrency capability of the program. Through coroutines, highly scalable and highly concurrent applications can be implemented to improve system performance and throughput.

The above is the method of implementing thread pool and coroutine at the bottom of PHP, and provides specific code examples. I hope it will provide some help for readers to understand and learn PHP concurrent programming.

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