Libevent 是一個用C語言編寫的、輕量級的開源高性能I/O框架，支持多種 I/O 多路復用技術： epoll、 poll、 dev/poll、 select 和 kqueue 等；支持 I/O，定時器和信號等事件；注冊事件優先級。PHP提供了對應的擴展 libevent、 Event 。

相比 libevent ext, event ext 擁有更好的性能表現和更全面的API，可以讓我們更友好的使用 Libevent。

安裝 Libevent 庫

php event 擴展 依賴 Libevent 庫，需要先編譯安裝（注意是 Libevent 庫，非 libevent 擴展）。

git clone --depth=1 https://github.com/nmathewson/Libevent.git cd Libevent ./autogen.sh  ./configure --prefix=/usr/local/libevent make && make install

安裝 Event 擴展

可以直接使用 pecl 安裝

pecl install event downloading event-2.5.3.tgz ... Starting to download event-2.5.3.tgz (140,913 bytes) ..............................done: 140,913 bytes 50 source files, building running: phpize Configuring for: PHP Api Version:         20180731 Zend Module Api No:      20180731 Zend Extension Api No:   320180731 Enable internal debugging in Event [no] :  Enable sockets support in Event [yes] :  libevent installation prefix [/usr] : /usr/local/libevent ... Build process completed successfully Installing '/usr/local/php/lib/php/extensions/no-debug-non-zts-20180731/event.so' install ok: channel://pecl.php.net/event-2.5.3 Extension event enabled in php.ini

查看安裝結果

[root@localhost ~]# php --ri event  event  Event support => enabled Sockets support => enabled Debug support => disabled Extra functionality support including HTTP, DNS, and RPC => enabled OpenSSL support => enabled Thread safety support => disabled Extension version => 2.5.3 libevent2 headers version => 2.2.0-alpha-dev