[root@localhost hooks]# pecl install xhprof
Failed to download pecl/xhprof within preferred state "stable", latest release is version 0.9.4, stability "beta", use "channel://pecl.php.net/xhprof-0.9.4" to install
sudo pecl install channel://pecl.php.net/xhprof-0.9.4
extension=xhprof.so
如果出现 phpize Can't find PHP headers in /usr/include/php
参考：
http://stackoverflow.com/questions/20827704/phpize-cant-find-php-headers-in-usr-include-php
https://segmentfault.com/a/1190000003509917
