How to benchmark efficiency of PHP script

Question

If you actually want to benchmark real world code, use tools like Xdebug and XHProf.

Xdebug is great for when you're working in dev/staging, and XHProf is a great tool for production and it's safe to run it there (as long as you read the instructions). The results of any one single page load aren't going to be as relevant as seeing how your code performs while the server is getting hammered to do a million other things as well and resources become scarce. This raises another question: are you bottlenecking on CPU? RAM? I/O?

You also need to look beyond just the code you are running in your scripts to how your scripts/pages are being served. What web server are you using? As an example, I can make nginx + PHP-FPM seriously out perform mod_php + Apache, which in turn gets trounced for serving static content by using a good CDN.

The next thing to consider is what you are trying to optimise for?

• Is the speed with which the page renders in the users browser the number one priority?
• Is getting each request to the server thrown back out as quickly as possible with smallest CPU consumption the goal?

The former can be helped by doing things like gzipping all resources sent to the browser, yet doing so could (in some circumstances) push you further away from the achieving the latter.

Hopefully all of the above can help show that carefully isolated 'lab' testing will not reflect the variables and problems that you will encounter in production, and that you must identify what your high level goal is and then what you can do to get there, before heading off down the micro/premature-optimisation route to hell.

To benchmark how fast your complete script runs on the server, there are plenty of tools you can use. First make sure your script (preg_match vs strpos for example) has to output the same results in order to qualify your test.

You can use:

• jmeter
• ApacheBench tool (see an example)
• dbench
• http_load
• curl-loader
• httperf
• siege
• vegeta
• the code you use is good too but with a bigger loop (like 1,000,000)

You will want to look at Xdebug and more specifically, Xdebug's profiling capabilities.

Basically, you enable the profiler, and every time you load a webpage it creates a cachegrind file that can be read with WinCacheGrind or KCacheGrind.

Xdebug can be a bit tricky to configure so here is the relevant section of my php.ini for reference:

[XDebug]
zend_extension = h:\xampp\php\ext\php_xdebug-2.1.1-5.3-vc6.dll
xdebug.remote_enable=true
xdebug.profiler_enable_trigger=1
xdebug.profiler_output_dir=h:\xampp\cachegrind
xdebug.profiler_output_name=callgrind.%t_%R.out

And here is a screenshot of a .out file in WinCacheGrind:

That should provide ample details about how efficent your PHP script it. You want to target the things that take the most amount of time. For example, you could optimize one function to take half the amount of time, but your efforts would be better served optimizing a function that is called dozens if not hundreds of times during a page load.

If you are curious, this is just an old version of a CMS I wrote for my own use.

Try https://github.com/fotuzlab/appgati

It allows to define steps in the code and reports time, memory usage, server load etc between two steps.

Something like:

    $appgati->Step('1');

    // Do some code ...

    $appgati->Step('2');

    $report = $appgati->Report('1', '2');
    print_r($report);

Sample output array:

Array
(
    [Clock time in seconds] => 1.9502429962158
    [Time taken in User Mode in seconds] => 0.632039
    [Time taken in System Mode in seconds] => 0.024001
    [Total time taken in Kernel in seconds] => 0.65604
    [Memory limit in MB] => 128
    [Memory usage in MB] => 18.237907409668
    [Peak memory usage in MB] => 19.579357147217
    [Average server load in last minute] => 0.47
    [Maximum resident shared size in KB] => 44900
    [Integral shared memory size] => 0
    [Integral unshared data size] => 0
    [Integral unshared stack size] => 
    [Number of page reclaims] => 12102
    [Number of page faults] => 6
    [Number of block input operations] => 192
    [Number of block output operations] => 
    [Number of messages sent] => 0
    [Number of messages received] => 0
    [Number of signals received] => 0
    [Number of voluntary context switches] => 606
    [Number of involuntary context switches] => 99
)