ID: 28642
Comment by: meyer at labeltools dot com
Reported By: am at andremeyer dot name
Status: Open
Bug Type: Performance problem
Operating System: Windows XP
PHP Version: 5.0.3
New Comment:
In the last paragraph, I meant
ini_set('assert.active', false);
of course. Sorry for the inconvenience.
Best regards
André Meyer
labeltools GmbH
Previous Comments:
------------------------------------------------------------------------
[2005-02-11 15:46:34] am at andremeyer dot name
Well, assertions are not really fast - actually, they are a bottle
neck. I modified my previous script. Look at this:
-----------------------------------------------------------------------------
<?php
$doAsserts = array(true, false);
foreach ($doAsserts as $doAssert)
{
ini_set('assert.active', $doAssert); // Turn assertions
on/off
$startTime = microtime(true);
for ($i = -500000; $i < 500000; $i++)
{
$result = $i * $i; // just to have
assert($result >= 0);
}
$endTime = microtime(1);
$time = $endTime - $startTime;
print "Elapsed time: $time\r\n";
}
?>
-----------------------------------------------------------------------------
Running this script, I get:
Elapsed time: 1.6357040405273
Elapsed time: 1.6131460666656
Now I comment the line "assert($result >= 0);" so that the script looks
like this:
-----------------------------------------------------------------------------
<?php
$doAsserts = array(true, false);
foreach ($doAsserts as $doAssert)
{
ini_set('assert.active', $doAssert); // Turn assertions
on/off
$startTime = microtime(true);
for ($i = -500000; $i < 500000; $i++)
{
$result = $i * $i; // just to have
//assert($result >= 0);
}
$endTime = microtime(1);
$time = $endTime - $startTime;
print "Elapsed time: $time\r\n";
}
?>
-----------------------------------------------------------------------------
When I run the script again, I get:
Elapsed time: 0.87688493728638
Elapsed time: 0.87343096733093
As you can see from this, about 50% of the execution time is spent in
the assertion! This would be still acceptable, if I could simply
disable assertions. Well, I can - by ini_set('assert.active', true); -
however, this only disables assertions without affecting the
performance at all. When disabling assertions, any assertion should
rather be considered as not existant (like a comment).
I hope this can be fixed in a future PHP version! Thanks.
------------------------------------------------------------------------
[2005-02-11 15:33:50] [EMAIL PROTECTED]
So, that means that assertions are so fast, that disabling them doesn't
affect script performance. Agree?
But if you change your code in this way:
assert(is_numeric($i));
=>
assert("is_numeric($i)");
you'll get expected results.
------------------------------------------------------------------------
[2004-06-05 16:05:23] am at andremeyer dot name
Description:
------------
Disabling assertions in PHP does not affect performance. After testing
my software with assertions, I want to disable assertions. I do this
with
ini_set('assert.active', false);
Surprisingly, the assert() statements in my software _still_ consume a
considerable amount of time.
Reproduce code:
---------------
<?php
$doAsserts = array(true, false);
foreach ($doAsserts as $doAssert)
{
ini_set('assert.active', $doAssert); // Turn assertions
on/off
$startTime = microtime(true);
for ($i = 0; $i < 1000000; $i++)
assert(is_numeric($i));
$endTime = microtime(1);
$time = $endTime - $startTime;
print "Elapsed time: $time\r\n";
}
?>
Expected result:
----------------
I expect something like:
Elapsed time: 1.3514750003815 // assertions turned on
Elapsed time: 0.4243453254354 // assertions turned off
I expect the elapsed time to decrease when turning assertions off.
Actual result:
--------------
Elapsed time: 1.3480539321899 // assertions turned on
Elapsed time: 1.3210921287537 // assertions turned off
As you can see, when turning assertions off, the elapsed time is nearly
the same. So I have to comment all my assertions in order to achieve a
better peformance.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=28642&edit=1
