Performance of static methods vs. functions

user_35292 0
Viewed 31676

In PHP, (unlike what I originally thought) there is an overhead of calling static methods vs simple functions.

On a very simple bench, the overhead is over 30% of the calling time (the method just returns the parameter):

// bench static method
$starttime = microtime(true);
for ($i = 0; $i< 10*1000*1000; $i++)
    SomeClass::doTest($i);

echo "Static Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench object method
$starttime = microtime(true);

for ($i = 0; $i< 10*1000*1000; $i++)
    $someObj->doTest($i);

echo "Object Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench function
$starttime = microtime(true);

for ($i = 0; $i< 10*1000*1000; $i++)
    something_doTest($i);

echo "Function Time: " , (microtime(true)-$starttime) , " ms\n";

outputs:

Static Time:   0.640204906464 ms
Object Time:   0.48961687088 ms
Function Time: 0.438289880753 ms

I know the actual time is still negligible unless I am actually calling something 1 million times, but the fact is that its there.

Will anyone care to try and explain what is happening behind the scenes?

update:
- added object method bench

oop php performance
8 Answers

I have followed up and done the same test with tons of iterations on PHP 8.0.3.

Opcache doesn't make much of a difference in this test.

Without opcache:

Function Time:  0.15400409698486 ms
Static Time:    0.15216994285583 ms
Object Time:    0.19552803039551 ms
Function Time:  0.1428279876709 ms
Static Time:    0.15206789970398 ms
Object Time:    0.22962498664856 ms
Function Time:  0.14341592788696 ms
Static Time:    0.15271997451782 ms
Object Time:    0.22965002059937 ms
Function Time:  0.1877110004425 ms
Static Time:    0.1523380279541 ms
Object Time:    0.2297830581665 ms
Function Time:  0.14280891418457 ms
Static Time:    0.15206098556519 ms
Object Time:    0.22957897186279 ms
Function Time:  0.14343619346619 ms
Static Time:    0.15272903442383 ms
Object Time:    0.22955703735352 ms
Function Time:  0.14328694343567 ms
Static Time:    0.15257477760315 ms
Object Time:    0.22901511192322 ms
Function Time:  0.14302086830139 ms
Static Time:    0.15233588218689 ms
Object Time:    0.22931504249573 ms
Function Time:  0.14283490180969 ms
Static Time:    0.15209102630615 ms
Object Time:    0.22963285446167 ms
Function Time:  0.14345097541809 ms
Static Time:    0.1527111530304 ms
Object Time:    0.22959303855896 ms

With opcache:

Function Time:  0.15897798538208 ms
Static Time:    0.15508103370667 ms
Object Time:    0.20733213424683 ms
Function Time:  0.14364719390869 ms
Static Time:    0.15376496315002 ms
Object Time:    0.18648386001587 ms
Function Time:  0.142982006073 ms
Static Time:    0.15293192863464 ms
Object Time:    0.20651602745056 ms
Function Time:  0.14292907714844 ms
Static Time:    0.15280795097351 ms
Object Time:    0.18663787841797 ms
Function Time:  0.14208316802979 ms
Static Time:    0.15290093421936 ms
Object Time:    0.20616102218628 ms
Function Time:  0.14288401603699 ms
Static Time:    0.15276694297791 ms
Object Time:    0.1861629486084 ms
Function Time:  0.14292597770691 ms
Static Time:    0.15292882919312 ms
Object Time:    0.20615196228027 ms
Function Time:  0.14286112785339 ms
Static Time:    0.1527988910675 ms
Object Time:    0.18700098991394 ms
Function Time:  0.14315795898438 ms
Static Time:    0.15318417549133 ms
Object Time:    0.20666813850403 ms
Function Time:  0.14300584793091 ms
Static Time:    0.15291309356689 ms
Object Time:    0.18714189529419 ms
user_156276660

I am following up what Morgan Touverey Quilling did but with PHP 7. Did 3 iterations incase it takes longer for the first run vs subsequent runs. Includes all classes as it might be done realistically. All included files just return the input.

include 'lib/global.php';
include 'SomeClass.php';
include 'StaticTest.php';

$someObj = new SomeClass();

$starttime = microtime(true);
for ($i = 0; $i< 10*100000; $i++)
    StaticTest::doStaticTest($i);

echo "<br>Static Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench object method
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    $someObj->doObjTest($i);

echo "<br>Object Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench function
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    something_doTest($i);

echo "<br>Function Time: " , (microtime(true)-$starttime) , " ms\n";

echo "<br>Static Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench object method
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    $someObj->doObjTest($i);

echo "<br>Object Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench function
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    something_doTest($i);

echo "<br>Function Time: " , (microtime(true)-$starttime) , " ms\n";

echo "<br>Static Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench object method
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    $someObj->doObjTest($i);

echo "<br>Object Time:   " , (microtime(true)-$starttime) , " ms\n";

// bench function
$starttime = microtime(true);

for ($i = 0; $i< 10*100000; $i++)
    something_doTest($i);

echo "<br>Function Time: " , (microtime(true)-$starttime) , " ms\n";

Just note that this is being done on one of my webhosts as its easier to switch php versions so might be some noise.

PHP 7.0.33

Static Time:   0.14076709747314 ms
Object Time:   0.16203689575195 ms
Function Time: 0.13194108009338 ms
Static Time:   0.13194918632507 ms
Object Time:   0.1779100894928 ms
Function Time: 0.13044309616089 ms
Static Time:   0.13045001029968 ms
Object Time:   0.16074585914612 ms
Function Time: 0.13029479980469 ms

PHP 7.1.29

Static Time:   0.13407206535339 ms
Object Time:   0.13267111778259 ms
Function Time: 0.1302649974823 ms
Static Time:   0.13027906417847 ms
Object Time:   0.1390438079834 ms
Function Time: 0.16873598098755 ms
Static Time:   0.16874289512634 ms
Object Time:   0.13901305198669 ms
Function Time: 0.12576103210449 ms

PHP 7.2.18:

Static Time:   0.1657600402832 ms
Object Time:   0.15700101852417 ms
Function Time: 0.1484169960022 ms
Static Time:   0.14842295646667 ms
Object Time:   0.16168689727783 ms
Function Time: 0.17508292198181 ms
Static Time:   0.17508983612061 ms
Object Time:   0.19771790504456 ms
Function Time: 0.1468551158905 ms

PHP 7.3.5

Static Time:   0.10701704025269 ms
Object Time:   0.097011089324951 ms
Function Time: 0.075740098953247 ms
Static Time:   0.07575798034668 ms
Object Time:   0.083790063858032 ms
Function Time: 0.072473049163818 ms
Static Time:   0.072479009628296 ms
Object Time:   0.081503868103027 ms
Function Time: 0.071882963180542 ms

PHP 7.2 seemed to run a lot slower than the other versions on average. I found their lowest number but it got into the low .2####'s too. Don't' have 7.4 as of right now.

user_111153320
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