xhprof is a opensource PHP extension developed by Facebook which allows to profile PHP code. It can be a very powerful tool if you’re able to understand what it outputs, and allows you to optimize your PHP application.

Installation Link to heading

Like any other php module, install goes through phpize:

$ wget http://pecl.php.net/get/xhprof-0.9.2.tgz
$ tar xvfz xhprof-0.9.2.tgz
$ cd xhprof-0.9.2/
$ cd extension
$ phpize
Configuring for:
PHP Api Version:         20041225
Zend Module Api No:      20060613
Zend Extension Api No:   220060519
$ ./configure
[...]
$ make
[...]
$ make install
[...]

You’ll have to add a new section in php.ini:

[xhprof]
extension=xhprof.so
xhprof.output_dir=/tmp/xhprof

And you’ll create the output directory:

$ mkdir /tmp/xhprof ; chmod a+rwt /tmp/xhprof

And finally, you’ll just have to install xhprof vizualisation code, and create a virtualhost for it (if you want to):

$ cp -Rp xhprof_html xhprof_lib /www/xhprof/

I’ve created a small script to retrieve quickly all available reports:

<?php
echo "<b>Available reports</b><br /><br />";

$dir = opendir('/tmp/xhprof');
if( ! $dir )
    die('No directory.');

while(FALSE != ($file = readdir($dir)))
{
    if($file[0] === '.')
        continue;
    $rep = explode('.', $file);
    echo "<a href='/xhprof_html/?run=" . $rep[0] . "&source=" . $rep[1] ."'>";
    echo $file;
    echo "</a><br />";
}

closedir($dir);

Code profiling Link to heading

To generate a report, you’ll have to start analysis engine and stop it at the end. In the following snippet, you’ll analyse the foo() function code:

<?php

// Initializing xhprof
xhprof_enable( XHPROF_FLAGS_CPU + XHPROF_FLAGS_MEMORY );

foo();

// Stopping xhprof & writing report
$xhprof_data = xhprof_disable();

include_once "/www/xhprof/xhprof_lib/utils/xhprof_lib.php";
include_once "/www/xhprof/xhprof_lib/utils/xhprof_runs.php";

$xhprof_runs = new XHProfRuns_Default();
$run_id = $xhprof_runs->save_run($xhprof_data, "foo");

Reports will be written in /tmp/xhprof and can be viewable directly with xhprof GUI. For more information, check the xhprof manual.