Everything

php

smart_str performance

php.internals

Brian J. France

23 years ago

This was a email I sent to Rasmus and another co-worker a while ago and forgot
to post the question to the list.  I just saw a commit converting zlib to
smart_str and figured I would send it now.

Comments?

Brian

----
I think I found what you were looking for yesterday.  implode has change
between 4.3 and 4.2.  4.2 does the double pass while 4.3 has changed to use a
new smart_str struct with smart_str_appendl function (a struct and function
calls around what I was doing in my extension).  I decided to run some
quick tests and here is what I have found:

for ( $i=0; $i < $count; $i++ ) {
$arr[] = rand_string_function(); // 12 characters
}

$start = gettimeofday();
$str = implode( "", $arr );
$end = gettimeofday();
printf( "%8.8d: %8.8f\n", $count, time_diff( $start, $end ) );

give this output:

4.3:
1:        0.00005100
2:        0.00002800
5:        0.00003700
10:        0.00006000
100:        0.00045600
1000:        0.00478600
10000:        0.06507500
100000:        1.71620700

4.2:
1:        0.00004700
2:        0.00002500
5:        0.00002800
10:        0.00004000
100:        0.00022400
1000:        0.00240700
10000:        0.03677200
100000:        0.37068200

While below 10 items I am sure it is hard to tell the difference, but it is
slower in all cases.  Any clue why one item is slower than two or even five?

Brian

Sterling Hughes

23 years ago

Switched it to avoid a copy on convert_to_string().  Performance in PHP5
now beats the previous version.

-Sterling

On Wed, 2003-05-21 at 12:36, Brian J. France wrote:

> This was a email I sent to Rasmus and another co-worker a while ago and forgot
> to post the question to the list.  I just saw a commit converting zlib to
> smart_str and figured I would send it now.
>
> Comments?
>
> Brian
>
> ----
> I think I found what you were looking for yesterday.  implode has change
> between 4.3 and 4.2.  4.2 does the double pass while 4.3 has changed to use a
> new smart_str struct with smart_str_appendl function (a struct and function
> calls around what I was doing in my extension).  I decided to run some
> quick tests and here is what I have found:
>
> for ( $i=0; $i < $count; $i++ ) {
>   $arr[] = rand_string_function(); // 12 characters
> }
>
> $start = gettimeofday();
> $str = implode( "", $arr );
> $end = gettimeofday();
> printf( "%8.8d: %8.8f\n", $count, time_diff( $start, $end ) );
>
> give this output:
>
> 4.3:
>        1:        0.00005100
>        2:        0.00002800
>        5:        0.00003700
>       10:        0.00006000
>      100:        0.00045600
>     1000:        0.00478600
>    10000:        0.06507500
>   100000:        1.71620700
>
> 4.2:
>        1:        0.00004700
>        2:        0.00002500
>        5:        0.00002800
>       10:        0.00004000
>      100:        0.00022400
>     1000:        0.00240700
>    10000:        0.03677200
>   100000:        0.37068200
>
> While below 10 items I am sure it is hard to tell the difference, but it is
> slower in all cases.  Any clue why one item is slower than two or even five?
>
> Brian

--
"First they ignore you, then they laugh at you,
then they fight you, then you win."
- Gandhi

Rasmus Lerdorf

23 years ago

This seems like a trivial bug fix to me.  Having implode() get
significantly slower from 4.2 to 4.3 doesn't make any sense to me.

-Rasmus

On 21 May 2003, Sterling Hughes wrote:

Moriyoshi Koizumi

23 years ago

Sterling Hughes <sterling@bumblebury.com> wrote:

> Switched it to avoid a copy on convert_to_string().  Performance in PHP5
> now beats the previous version.

Your patch doesn't seem to work for me.

<?php
$foo = array();
$array = array(&$foo, &$foo);

$test = implode("", $array);
var_dump($array);
?>

$ php test.php
array(2) {
[0]=>
&string(5) "Array"
[1]=>
&string(5) "Array"
}

Moriyoshi

Sterling Hughes

23 years ago

On Wed, 2003-05-21 at 13:17, Moriyoshi Koizumi wrote:

> Sterling Hughes <sterling@bumblebury.com> wrote:
>
> > Switched it to avoid a copy on convert_to_string().  Performance in PHP5
> > now beats the previous version.
>
> Your patch doesn't seem to work for me.
>
> <?php
> $foo = array();
> $array = array(&$foo, &$foo);
>
> $test = implode("", $array);
> var_dump($array);
> ?>
>
> $ php test.php
> array(2) {
>   [0]=>
>   &string(5) "Array"
>   [1]=>
>   &string(5) "Array"
> }

Well, one shouldn't be passing references, :) but I'll have a quick fix
for that, one moment.

-Sterling

--
"That stuff's easy compared to installing Horde"
- Alan Knowles, In response to my applause for creating a LALR
parser for PHP.