#51122 [Bgs]: the iteration on arrays with calling functions is very slow
ID: 51122
Updated by: rasmus@php.net
Reported By: y_kopel at walla dot com
Status: Bogus
Bug Type: Arrays related
Operating System: linux
PHP Version: 5.3.1
New Comment:
With gc on there are gc checks on every iteration. Just because it
doesn't use more memory doesn't mean that gc does add more overhead.
Previous Comments:
------------------------------------------------------------------------
[2010-02-24 06:57:03] y_kopel at walla dot com
but...
with and without gc_enable/gc_disable
it consume the same ammount of memory
but work 40 times longer with gc_enable
------------------------------------------------------------------------
[2010-02-23 13:02:23] jani@php.net
Or run the script in 32bit system (and turn of GC :).
With latest SVN checkout of PHP_5_3:
$ src/build/php_5_3/sapi/cli/php -dmemory_limit=1G t.php
1.2259361743927
$ src/build/php_5_3/sapi/cli/php -dmemory_limit=1G -dzend.enable_gc=0
t.php
0.70840787887573
And with latest SVN checkout of PHP_5_2:
$ src/build/php_5_2/sapi/cli/php -dmemory_limit=1G t.php
0.69131684303284
Not noticeable even.
------------------------------------------------------------------------
[2010-02-23 12:59:02] jani@php.net
Just turn off garbage collection if this is a problem for you.
(zend.enable_gc = off in php.ini)
------------------------------------------------------------------------
[2010-02-23 11:54:00] y_kopel at walla dot com
shorter code:
<?php
for ($i = 0 ;$i < 1000000 ; $i++){
$users[$i]['SUM'] = 2;
}
$start = microtime(true);
$sum = 0;
foreach ($users as &$u){
if ($u['SUM'] > 1){ $sum++;}
}
echo microtime(true) - $start."\n";
?>
OUTPUT
======
php 5.2.1
=========
0.328261852264
php 5.3.1
=========
42.350708961487
------------------------------------------------------------------------
[2010-02-23 11:40:36] y_kopel at walla dot com
Description:
------------
the iteration on arrays with calling functions is very slow
comparing php 5.2.1 to 5.3.1
Reproduce code:
---------------
<?php
define("FLOATING_POINT",6);
function ww($f){
echo sprintf("%.".FLOATING_POINT."f", $f)."\n";
}
class A{
protected $users;
function __construct(){
for ($i = 0 ;$i < 100000 ; $i++){
$this->users[$i]['ELEMENT'] = array("a","b");
$this->users[$i]['SUM'] = 2;
}
}
function check_more_than_one_element(){
$sum = 0;
foreach ($this->users as &$u){
if (count($u['ELEMENT']) > 1){
$sum++;
}
}
return $sum;
}
function a_check_more_than_one_element(){
$sum = 0;
foreach ($this->users as &$u){
if ($u['SUM'] > 1){
$sum++;
}
}
return $sum;
}
}
$a = new A();
$start = microtime(true);
echo "-----\n";
for ($i = 0 ;$i < 5 ; $i++){
$a->check_more_than_one_element();
$a->check_more_than_one_element();
$a->check_more_than_one_element();
$a->check_more_than_one_element();
}
echo "-----\n";
echo microtime(true) - $start."\n";
$a = new A();
$start = microtime(true);
echo "-----\n";
for ($i = 0 ;$i < 5 ; $i++){
$a->a_check_more_than_one_element();
$a->a_check_more_than_one_element();
$a->a_check_more_than_one_element();
$a->a_check_more_than_one_element();
}
echo "-----\n";
echo microtime(true) - $start."\n";
?>
Expected result:
----------------
php 5.2.1
=========
-----
-----
1.75261092186
-----
-----
1.05390191078
Actual result:
--------------
php 5.3.1
=========
-----
-----
58.992564916611
-----
-----
30.829360961914
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=51122&edit=1
Thread (7 messages)