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:
It has to do something with object allocation because the problem does
NOT occur with this loop:
foreach (range(1, 1000000) as $i) {
$a []= array($i);
}
Previous Comments:
------------------------------------------------------------------------
[2009-12-02 09:11:20] notarealemail at nodomain dot com
Sorry, forgotten a benchmark:
time: 0.90 secs, memory usage 219.38 MiB. (original loop, GC disabled)
So the problem seems more related to foreach+array+garbage collector
than class allocation
------------------------------------------------------------------------
[2009-12-02 08:59:11] [email protected]
Not exactly faster but better than with foreach():
[j...@localhost ~]$ php -d memory_limit=2G t.php
time: 2.73 secs, memory usage 371.39 MiB.
[j...@localhost ~]$ src/build/php_5_3/sapi/cli/php -d memory_limit=2G
t.php
time: 3.05 secs, memory usage 383.46 MiB.
------------------------------------------------------------------------
[2009-12-02 08:42:56] notarealemail at nodomain dot com
Simply changing the loop from
foreach (range(1, 1000000) as $i)
to
for ( $i = 0; $i < 1000000; $i++ )
Makes php 5.3.1 (win xp vc9 nots cli) run "normal", even faster than
5.2.11 (same configuration).
Performance (php 5.3.1):
time: 8.23 secs, memory usage 219.38 MiB. (original loop)
time: 0.91 secs, memory usage 219.39 MiB. (modified loop)
time: 0.72 secs, memory usage 219.38 MiB. (modified loop, GC disabled)
Tested on a E8400 3GHz.
------------------------------------------------------------------------
[2009-12-01 14:46:39] [email protected]
See also bug #48781 (propably related as well)
------------------------------------------------------------------------
[2009-12-01 13:48:23] rlillack at yasni dot de
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.
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