Even the most experienced programmer can be lazy. After all, what are a few milliseconds of extra load time here or there? Users won’t notice, right?

That sort of thinking is a slippery slope, though. A fraction of a second here or there, measured over thousand of visits, can add up to lost conversions. A little extra processing time per execution, over millions of executions, can add up to significant power consumption and wear and tear on the server. And since most good programming habits require no additional work on the part of the programmer, there’s a real business case to be made against lazy programming.

It’s time to break out of those lazy habits and start coding with performance in mind. Practice these ten PHP performance tips and watch your code go from sluggish to speedy in no time.

  1. Use echo instead of print(). As a language construct rather than a function, echo has a slight performance advantage over print().
  2. Echo with commas, not periods. I’m a repeat offender of this one. If you use periods, PHP has to concatenate the string before it outputs. If you use commas, it just outputs them in order with no extra processing.
  3. Avoid function tests in loop conditionals. If you’re looping through an array, for example, count() it beforehand, store the value in a variable, and use that for your test. This way, you avoid needlessly firing the test function with every loop iteration.
  4. Use include() and require() instead of include_once() and require_once(). There’s a lot of work involved in checking to see if a file has already been included. Sometimes it’s necessary, but you should default to include() and require() in most situations.
  5. Use full file paths on include/require statements. Normalizing a relative file path can be expensive; giving PHP the absolute path (or even “./file.inc”) avoids the extra step.
  6. Favor built-in functions over custom functions. Since PHP has to take the extra step of interpreting your custom functions, built-in functions have a performance advantage. More importantly, there are a lot of useful built-in functions that you may never learn about if you always default to writing your own.
  7. Avoid needlessly copying variables. If the variable is quite large, this could result in a lot of extra processing. Use the copy you already whenever possible, even if it doesn’t look pretty (e.g., $_POST[‘somevariable’]).
  8. Pass unchanged variables to a function by reference rather than value. This goes hand-in-hand with the point about needlessly copying variables. Much of the time, your functions only need to use the values from their parameters without changing them. In such cases, you can safely pass those parameters by reference (e.g., function(&$parameter) rather than function($parameter)) and avoid having to make memory-intensive copies.
  9. Debug with error_reporting(E_ALL). Every warning is a performance improvement waiting to happen, but only if you can see it. Cleaning up warnings and errors beforehand can also keep you from using @ error suppression, which is expensive. Just don’t forget to turn off error reporting when you’re done; warnings and errors are expensive as well.
  10. Ditch double quotes for single quotes. There’s some disagreement, but the common wisdom is that PHP has to do extra processing on a string in double quotes to see if it contains any variables. Concatenation with single quotes is marginally faster.

Sources

Tips from this article were pulled from the following sources.

19 thoughts on “10 Performance Tips to Speed Up PHP

  1. This tips really help me a lot and make me pursue to really write my code in a proper manner.

  2. Hello,

    Just some notices after some tests:

    4. Didn’t see any difference when switching from (include|require)_once to (include|require). Tested on a test website with more than 20-30 requires.

    10. Tested in a for loop, i didn’t get any difference.

    My tests were done with php 5.2+

  3. Thanks for testing, PERECil. Some of these tips may very well be dated compared to the latest versions of PHP. I know there’s a lot of debate about single versus double quotes, which is why I included that tip at the end where other guides may have included it at the beginning. Out of curiosity, did you test the others, and, if so, how did they pan out?

  4. Re point 7, needlessly copying variables. Using $_POST[‘somevariable’] over say $somevar = $_POST[‘somevariable’] and then accessing $somevar many times is much slower than just using $somevar. PHP has to lookup the name in the POST array each time.

  5. Without knowing more about your setup, Texx, I can’t say for sure, but my gut tells me that moving your included information into a database and pulling it out with a query would vastly simplify things for you. For example, you might set up a MySQL database, propagate it with your pricing information, and pull the data into a $prices array with something simple like this:

    <?php
    mysql_connect('hostname', 'username', 'password');
    mysql_select_db('decking_prices_db');
    $prices = mysql_query("SELECT product_id, price FROM decking_prices");
    $price = array();
    while ($price_data = mysql_fetch_object($prices)){
      $price[$price_data->product_id] = $price_data->price;
    }
    mysql_close();
    ?>

  6. Thanks for testing, PERECil. Some of these tips may very well be dated compared to the latest versions of PHP. I know there’s a lot of debate about single versus double quotes, which is why I included that tip at the end where other guides may have included it at the beginning. Out of curiosity, did you test the others, and, if so, how did they pan out?

  7. I tested comma vs periods with simple line :

    echo “hello ” , “hello ” , “helo ” , “hello ” , “hello ” , “helo ” , “hello ” , “hello ” , “helo “;

    and also

    echo “hello ” . “hello ” . “helo ” . “hello ” . “hello ” . “helo ” . “hello ” . “hello ” . “helo “;

    and running time with comma is greater than dot!!!

    with dot it is 0.00026893615722656 but with comma it is 0.0014798641204834, and as far as I know 0.0002 is smaller than 0.001.

    is there anything wrong with my test ?

  8. Hi, nice post. But your tip

    Use include() and require() instead of include_once() and require_once().

    is not very useful because I run some tests and this is the output:

    Include:0.027546
    Include_once:0.006724
    Require:0.02996
    Require_once:0.005317

    Windows 7, Intel Core i3 2.30 GHz, 4 GB RAM DDR3 etc.

  9. “8. Pass unchanged variables to a function by reference rather than value.”
    Actually it’s the other way round, passing values is faster in PHP, as it uses the ‘copy on write’ technique.

  10. Re:toraj, Werewolf, and spec, given that this post is more than three years old, I would expect some of the guidance to have changed by now. It only makes sense for PHP and server configurations to change over time to accommodate the way most people program.

    All the better for me, since I’m still a repeat offender of many of these tips. 😉

  11. Nice list of tips. But when it comes to copying $_GET or $_POST variables, I thought this was usually done for security reasons. I did more searching and found that there might be some truth to that (see http://phpsec.org/projects/guide/1.html). In short, the suggested method appears to be validating the data and if it is clean, then save the cleaned up version to it’s own variable and use that. Is this correct?

  12. ad17 Aaron:copying variables means extra memory resources. Copying for security reasons is a bad habbit. No guarantee you made your variable safe! Best habbit: ALL USER INPUT (POST/GET/COOKIES/HEADER-INFO) ARE DANGEROUS VALUES!
    You just ALWAYS consider these values as extremely dangerous. Consequent escaping of all these values are critical for your sites safety. After made safe, there is absolutely no reason to copy them to other variabels. Concentrate on good escaping, renaming/copying values isn’t a safety procedure. It’s even worse: you dont recognize the variable was actually userinput. So copying is a real bad habbit too.

  13. The performance of your PHP based website also depends on the version, hosting and stack you are using. I have hosted my website on AWS with Cloudways platform (https://www.cloudways.com/en/php-cloud-hosting.php ), which uses Apache, Varnish, Memcached and Nginx as a stack. Along with that, I also use Cloudflare CDN. I ran benchmarks on my PHP 7 website and got 4ms response time with 250 concurrent users, which is quite fast.

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