With the continuous upgrading of computer hardware, multi-core processors have become mainstream. In order to better utilize the performance of multi-core processors, multi-process programming has become a very important technology. In the PHP language, multi-process programming is even more essential, especially when processing large-scale data. However, PHP had very limited support for multi-process programming in early versions, and it was not until PHP 7.0 that multi-process programming was officially supported. This article will introduce in detail how to use PHP7.0 for multi-process programming.
1. What is multi-process programming?
Multi-process programming refers to running multiple processes on the same computer, and each process runs independently. Multi-process programming can make full use of the performance of multi-core processors and achieve parallel processing. In actual development, multi-process programming can be applied to many scenarios, such as batch data processing tasks, crawlers, message queues, etc.
2. Advantages of PHP7.0 multi-process programming
PHP7.0 has added support for multi-process programming, which is closely related to PHP's goal of improving operating efficiency. The main advantages of PHP7.0 in multi-process programming are as follows:
3. How to implement multi-process programming in PHP7.0?
In PHP7.0, there are several common implementation methods to implement multi-process programming, including process manager, pcntl extension, swoole extension, etc.
The process manager can use Linux's fork and execve system calls to create child processes, and itself serves as the parent process to manage the child process. operate. The most common PHP process manager is PHP-FPM (FastCGI Process Manager), which can handle multiple requests and excels in terms of performance. At the same time, PHP-FPM itself is also a multi-process application, which can manage and monitor working processes, and can also perform hot restart and other operations.
pcntl extension provides a PHP interface that can be used to create and control processes and child processes. Through pcntl extension, most functions of multi-process programming can be realized, including process creation, signal processing, inter-process communication, etc.
The following are some commonly used functions of pcntl extension:
(1) pcntl_fork(): Create a child process and return 0 in the child process, and return a value greater than 0 in the parent process integer.
(2) pcntl_wait(): Wait for a signal or the child process to terminate, and return the process number of the child process.
(3) pcntl_signal(): Register a signal processing function.
(4)pcntl_alarm(): Send a SIGALRM signal after the specified time.
(5)pcntl_exec(): Overwrite the current process with a new process.
Swoole is a network communication framework for PHP and an important tool for PHP multi-process programming. The swoole extension provides a series of high-performance APIs for network communications such as TCP, UDP, HTTP, etc., which also includes APIs for multi-process programming. Using swoole extensions can easily implement high-concurrency and high-performance applications. The following are some common functions of swoole extension:
(1) swoole_process: used to create and manage multiple processes.
(2) swoole_event_add: used to associate a file descriptor to the swoole event loop.
(3) swoole_event_write: used to write data to the registered file descriptor in the event loop.
(4) swoole_event_set: used to set the callback function in the event loop.
(5) swoole_timer_tick: used for timer to execute a certain callback function in a loop.
4. Issues that need to be paid attention to in multi-process programming
Although multi-process programming can greatly improve the performance of PHP programs, there are also some issues that need to be paid attention to. The following are some of the most critical issues:
In multi-process programming, different processes need to communicate with each other in order to complete tasks together, such as data sharing, signal notification, etc. Commonly used inter-process communication methods include shared memory, message queues, semaphores, etc. When performing multi-process programming, you need to choose an appropriate inter-process communication method based on actual needs.
In multi-process programming, different processes use independent memory spaces, so special attention needs to be paid to memory issues. Some common memory problems include memory leaks, memory bloat, etc. When doing multi-process programming, you need to design and use memory carefully to avoid memory problems affecting program performance.
In multi-process programming, process management is a very important issue. The creation, destruction, monitoring, etc. of processes all need to be managed. If not managed properly, it can easily cause problems such as process hangs and crashes. Therefore, a good process management mechanism needs to be designed to ensure the stability and reliability of the program.
5. Conclusion
The emergence of PHP7.0 provides more powerful and flexible support for multi-process programming in the PHP language. According to actual needs, you can use process manager, pcntl extension, swoole extension, etc. to implement multi-process programming. When doing multi-process programming, you need to pay attention to some issues, including inter-process communication, memory issues, process management, etc. By carefully addressing these issues, the performance of multi-core processors can be better utilized and provide a more efficient and reliable execution environment for applications.
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