Performance Testing with PHP

After writing some functions or classes its good idea to make sure your code is executing in a timely fashion, especially for web applications. For PHP I use a function derived from the chronmeter class to look for bottle necks (the function is below or download it here).

We recently ran into a problem of a web form running particular slow. It had the following functionality.

I architected the form and was letting one of our interns implement it. Everything seemed pretty straight forward - this code should fly. After the site went live, I checked out the form and found it running slow. Using the chronometer function I paired it down to our phpmailer. Turns out we were using php’s built in mail function and not phpmailer.

After switching to phpmailer and setting the option to smtp, I cut the runtime in half. I then realized we were sending out 2 emails and each time opening/closing an smtp connection. I refactored so only 1 connection was opened. Here are the results of the average form runtime:

To use the chronometer function, simply call it before a class or function call and then call it right after it .


$chronometer(); //start
$this->SendSalesEmail($_POST);
$runtime = chronometer();
print “SendSalesEmail took: $runtime”;

$CHRONO_STARTTIME = 0;

define(”RET_TIME”, “s”); //Can be set to “ms” for milliseconds or “s” for seconds
function chronometer()
{
global $CHRONO_STARTTIME;

$now = microtime(TRUE); // float, in _seconds_

if (RET_TIME === ’s’) {
$now = $now + time();
$malt = 1;
$round = 7;
} elseif (RET_TIME === ‘ms’) {
$malt = 1000;
$round = 3;
} else {
die(”Unsupported RET_TIME value”);
}

if ($CHRONO_STARTTIME > 0) {
/* Stop the chronometer : return the amount of time since it was started,
in ms with a precision of 3 decimal places, and reset the start time.
We could factor the multiplication by 1000 (which converts seconds
into milliseconds) to save memory, but considering that floats can
reach e+308 but only carry 14 decimals, this is certainly more precise */

$retElapsed = round($now * $malt - $CHRONO_STARTTIME * $malt, $round);

$CHRONO_STARTTIME = $now;

return $retElapsed;
} else {
// Start the chronometer : save the starting time

$CHRONO_STARTTIME = $now;

return 0;
}
}
?>php_chronometer.txt

Written by Tim on February 10th, 2006 with 5 comments.
Read more articles on php.

• [+] Digg: Feature this article
• [+] Del.icio.us: Bookmark this article
• [+] Furl: Bookmark this article