ID: 50351
Comment by: rlillack at yasni dot de
Reported By: rlillack at yasni dot de
Status: Verified
Bug Type: Scripting Engine problem
Operating System: 64/32bit linux
PHP Version: 5.3.1
New Comment:
This seems to be related to the new cyclic garbage collector trying to
free memory after each allocation?!
A rather simple workaround is to insert gc_disable() before and
gc_enable() after entering the loop.
Previous Comments:
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[2009-12-01 13:38:56] j...@php.net
My results were done with i686..
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[2009-12-01 13:37:27] j...@php.net
[j...@localhost ~]$ src/build/php_5_2/sapi/cli/php -n -d
memory_limit=2G t.php
time: 4.10 secs, memory usage 371.39 MiB.
[j...@localhost ~]$ src/build/php_5_3/sapi/cli/php -n -d
memory_limit=2G t.php
time: 25.97 secs, memory usage 383.46 MiB.
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[2009-12-01 12:53:42] rlillack at yasni dot de
Description:
------------
PHP 5.3 did indeed introduce many performance improvements, but we
spotted a rather hard regression with handling a large amount of
objects that are allocated at the same time.
Running the following test case on one of our web servers yield this
result with a vanilla build of 5.2.11:
time: 1.28 secs, memory usage 376.48 MiB.
and this with 5.3.1:
time: 13.44 secs, memory usage 400.62 MiB.
(command line in both cases: PREFIX/bin/php -d memory_limit=2G
testcase.php)
The regression at least since the PHP 5.3 release candidates.
Both were fresh build straight from the tarball, No extensions, etc.
Opcode caches do not help. --with-zend-vm does not help.
Reproduce code:
---------------
<?php
$start = microtime(TRUE);
$a = array();
foreach (range(1, 1000000) as $i) {
$a []= new StdClass;
}
printf("time: %s secs, memory usage %s MiB.\n",
number_format(microtime(TRUE) - $start, 2),
number_format(memory_get_usage() / 1024 / 1024, 2));
Expected result:
----------------
PHP 5.3.1 should not be any slower than 5.2.11 is. :)
Actual result:
--------------
PHP 5.3.1 is ten times slower in this test case.
One of our apps does only handle 1/4th queries/s with 5.3 on a
production server.
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--
Edit this bug report at http://bugs.php.net/?id=50351&edit=1
