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 多路複用技術： epoll、 poll、 dev/poll、 select 和 kqueue 等；支持 I/O，定時器和信號等事件；註冊事件優先級。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