Tracking the script execution time in PHP


Question

PHP must track the amount of CPU time a particular script has used in order to enforce the max_execution_time limit.

Is there a way to get access to this inside of the script? I'd like to include some logging with my tests about how much CPU was burnt in the actual PHP (the time is not incremented when the script is sitting and waiting for the database).

I am using a Linux box.

1
260
8/7/2014 9:21:03 PM

Accepted Answer

On unixoid systems (and in php 7+ on Windows as well), you can use getrusage, like:

// Script start
$rustart = getrusage();

// Code ...

// Script end
function rutime($ru, $rus, $index) {
    return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
     -  ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
}

$ru = getrusage();
echo "This process used " . rutime($ru, $rustart, "utime") .
    " ms for its computations\n";
echo "It spent " . rutime($ru, $rustart, "stime") .
    " ms in system calls\n";

Note that you don't need to calculate a difference if you are spawning a php instance for every test.

209
3/31/2018 4:14:59 PM

If all you need is the wall-clock time, rather than the CPU execution time, then it is simple to calculate:

//place this before any script you want to calculate time
$time_start = microtime(true); 

//sample script
for($i=0; $i<1000; $i++){
 //do anything
}

$time_end = microtime(true);

//dividing with 60 will give the execution time in minutes otherwise seconds
$execution_time = ($time_end - $time_start)/60;

//execution time of the script
echo '<b>Total Execution Time:</b> '.$execution_time.' Mins';
// if you get weird results, use number_format((float) $execution_time, 10) 

Note that this will include time that PHP is sat waiting for external resources such as disks or databases, which is not used for max_execution_time.


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