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implode() speedup in PHP4

php.internals

Alexander Valyalkin

21 years ago

I've posted patch last summer http://www.zend.com/zend/week/pat/pat5.txt
which imporves performance of implode() function in PHP4, but nobody
doesn't
commit it yet. Can anybody explain the reason?

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Christian Stadler

21 years ago

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Alexander Valyalkin schrieb:

> I've posted patch last summer http://www.zend.com/zend/week/pat/pat5.txt
> which imporves performance of implode() function in PHP4, but nobody
> doesn't
> commit it yet. Can anybody explain the reason?

After applying the change to ext/standard/string.c in PHP4 the following
Test failed:
Bug #22224 (implode changes object references in array)
[ext/standard/tests/strings/bug22224.phpt]

Regards,
Christian Stadler
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Alexander Valyalkin

21 years ago

> After applying the change to ext/standard/string.c in PHP4 the following
> Test failed:
> Bug #22224 (implode changes object references in array)
> [ext/standard/tests/strings/bug22224.phpt]
>
> Regards,
>   Christian Stadler

I understood my fault. I didn't notice condition
if (!(*ppzv)->is_ref) { }
in convert_to_ex_master() macro.

But compare execution time of the following test on PHP4 & PHP5:
<?
function getmicrotime()
{
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
$t = getmicrotime();
$s = str_repeat('a', 1 << 24);
$a = implode(",", array($s, $s));
echo getmicrotime() - $t;
?>

I think, it will be good idea to fix such time wasting in PHP4.

Moriyoshi Koizumi

21 years ago

On 2005/03/19, at 3:41, Alexander Valyalkin wrote:

>
> I've posted patch last summer
> http://www.zend.com/zend/week/pat/pat5.txt
> which imporves performance of implode() function in PHP4, but nobody
> doesn't
> commit it yet. Can anybody explain the reason?

Because convert_to_string_ex() modifies the content of every element
that is not of string type.

<?php
$arrays = array(array(), array(), array());
var_dump(implode('', $arrays));
var_dump($arrays);
?>

We already have an optimisation in the 5.x branches.
I think it is appliable to the 4.3 branch.

Moriyoshi

Derick Rethans

21 years ago

On Sat, 19 Mar 2005, Moriyoshi Koizumi wrote:

> <?php
> $arrays = array(array(), array(), array());
> var_dump(implode('', $arrays));
> var_dump($arrays);
> ?>
>
> We already have an optimisation in the 5.x branches.
> I think it is appliable to the 4.3 branch.

4.3 is only for bugfixes!

Derick

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Derick Rethans
http://derickrethans.nl | http://ez.no | http://xdebug.org

Moriyoshi Koizumi

21 years ago

On 2005/03/19, at 6:14, Derick Rethans wrote:

> On Sat, 19 Mar 2005, Moriyoshi Koizumi wrote:
>
>> <?php
>> $arrays = array(array(), array(), array());
>> var_dump(implode('', $arrays));
>> var_dump($arrays);
>> ?>
>>
>> We already have an optimisation in the 5.x branches.
>> I think it is appliable to the 4.3 branch.
>
> 4.3 is only for bugfixes!

It didn't mean that the fix should be in the 4.3. What was it
that excited you so much? :)

Moriyoshi

Andi Gutmans

21 years ago

Just make sure that zval's which are isolated with convert_to_string_ex()
are only used as read-only.

At 09:41 PM 3/18/2005 +0300, Alexander Valyalkin wrote: