What problem did swoole solve?

#php's existing application methods are all based on http, which is relatively weak for situations that require fast real-time response. For example, online games or push services generally need to maintain long-term communication with users. A tcp connection for real-time response and push information.

#swoole is designed to solve such application scenarios. (Recommended learning: SWOOLE Video Tutorial )

# Swoole Realization

Swoole is written in pure C, not depending on other third -party libraries .

swoole does not use libevent, so there is no need to install libevent

swoole does not rely on PHP's stream/sockets/pcntl/posix/sysvmsg and other extensions

socket Part

swoole uses the underlying socket system call.

IO event loop

The event loop of the main process uses select/poll, because there are only a few file descriptors in the main thread, just use select/poll

Use epoll/kqueue in the reactor thread/worker process

The task process does not have an event loop, and the process will cycle and block the read pipe

Many people use strace -p to view swoole The main process can only see the poll system call. The correct way to view it is strace -f -p

Multiple processes/multithreads

Multiple processes use the fork() system call

Multiple threads use pthread thread library

EventFd

Swoole uses eventfd as a mechanism for thread/inter-process message notification.

Timerfd

Swoole uses timerfd to implement the timer

SIgnalfd

signalfd is used in swoole To achieve signal shielding and processing. It can effectively avoid the problem of threads/processes being interrupted by signals and the system calling restart. The reactor thread will not receive any signals in the main process.

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