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Subject: =?gb18030?B?u9i4tKO6QnVnICM3Nzg3OSBbT3BuLT5OYWJdOiBV?= =?gb18030?B?c2FibGUgbWVtb3J5?=
From: "=?gb18030?B?1Kfp5MGnqVPB+cPF?=" <2771680986 () qq ! com>
Date: 2019-04-12 8:24:29
Message-ID: tencent_8B2890D21CCDA018F7AEC7D88DB4FAD8F009 () qq ! com
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what's the meaning £¿ speak Chinese------------------ ÔʼÓʼþ ------------------
·¢¼þÈË: "nikic"<nikic@php.net>
·¢ËÍʱ¼ä: 2019Äê4Ô 12ÈÕ(ÐÇÆÚÎå) Ï Îç3:48
ÊÕ¼þÈË: "php-bugs"<php-bugs@lists.php.net>;"php-qa"<php-qa@lists.php.net>;
Ö÷Ìâ: Bug #77879 [Opn->Nab]: Usable memory
Edit report at https://bugs.php.net/bug.php?id=77879&edit=1
ID: 77879
Updated by: nikic@php.net
Reported by: xxalfa at gmail dot com
Summary: Usable memory
-Status: Open
+Status: Not a bug
Type: Bug
Package: Testing related
Operating System: Windows
PHP Version: 7.3.4
Block user comment: N
Private report: N
New Comment:
Memory allocations are restricted to certain sizes for performance reasons. Small \
allocations are rounded up the next largest bin size. When the memory is reallocated \
with a size that still fits within the same bin, the reallocation is performed \
in-place and the reported memory usage will not change.
Previous Comments:
------------------------------------------------------------------------
[2019-04-12 03:06:55] requinix@php.net
No, the memory does not increase by 1024 each time. It increases by whatever amount \
PHP allocates in order to expand the string by another 1024 bytes. As your output \
shows, the last step it went up by 4096 - enough for approximately 4 increases.
Should it have only allocated 1k? Is it bad that PHP is reserving more memory than \
the precise amount it needs at that given moment?
------------------------------------------------------------------------
[2019-04-12 02:58:35] xxalfa at gmail dot com
The script executes successfully because it has detected because the level of memory \
has not changed. However, the level increases by 1024 per cycle, if the function were \
to work properly, the script would continue to work. That's why it's a bug.
------------------------------------------------------------------------
[2019-04-12 02:26:32] requinix@php.net
Your script is quitting because PHP didn't need to allocate more memory to handle \
another 1k characters. Why is that a bug?
------------------------------------------------------------------------
[2019-04-12 01:48:30] xxalfa at gmail dot com
Description:
------------
The following script fills the memory with pointless data. Now the problem: From one \
point, the function "memory_get_usage" returns the same value, although the level has \
changed. This is important if you want to process data and save it only when a \
certain number of results have been generated. The second problem: Why are only 40% \
usable?
Test script:
---------------
<?php
// C:\Users\User\Desktop\php-on-limit.cmd
// @echo off
// title PHP Development Server
// cd "%cd%"
// rem "C:\php\php.exe" "php-on-limit.php"
// "C:\php\php.exe" "-d memory_limit=16M" "php-on-limit.php"
// pause
// C:\Users\User\Desktop\php-on-limit.php [PHP:7.3.3][PID:6336]
//-------------------------------------------------
// HEAD
//-------------------------------------------------
declare( strict_types = 1 );
header( 'Content-Type:text/plain' );
error_reporting( E_ALL );
ini_set( 'display_errors', '1' );
ini_set( 'html_errors', '0' );
define( 'CORE_DIR', dirname( __FILE__ ) . DIRECTORY_SEPARATOR );
isset( $argv ) or trigger_error( 'This is a command terminal application.', \
E_USER_ERROR );
echo __FILE__ . ' [PHP:' . phpversion() . '][PID:' . getmypid() . ']' . PHP_EOL . \
PHP_EOL;
//-------------------------------------------------
// CODE
//-------------------------------------------------
$measuring_point_of_time = microtime( true );
$memory_limit = conversion_back_to_bytes( ini_get( 'memory_limit' ) );
echo 'memory_limit -- ' . human_readable_file_size( $memory_limit ) . ' -- \
defined limit' . PHP_EOL;
// $memory_limit *= 0.48; // 48% of 128M can only be used
// $memory_limit *= 0.47; // 47% of 64M can only be used
$memory_limit *= 0.40; // 40% of 16M can only be used
// If the 40% is exceeded, it comes to a fatal error, which is not desirable.
// Fatal error: Allowed memory size of 16 MByte exhausted (tried to allocate 6 \
MByte).
echo 'memory_limit -- ' . human_readable_file_size( $memory_limit ) . ' -- usable \
limit' . PHP_EOL;
echo 'memory_allocated -- ' . human_readable_file_size( memory_get_usage( true ) \
) . ' -- memory_used -- ' . memory_get_usage() . PHP_EOL;
$something_has_to_be_calculated = true;
$results_of_the_calculations = null;
$last_memory_usage = memory_get_usage();
while ( $something_has_to_be_calculated )
{
$results_of_the_calculations .= str_repeat( '1', 1024 );
$currently_memory_usage = memory_get_usage();
if ( last_memory_usage )
{
echo PHP_EOL . 'Process recording: Memory function has not changed. \
currently_memory_usage and last_memory_usage are ' . $currently_memory_usage . \
PHP_EOL;
break;
}
// echo chr( 0xD );
echo 'memory_allocated -- ' . human_readable_file_size( memory_get_usage( \
true ) ) . ' -- memory_used -- ' . memory_get_usage() . ' -- data_length -- ' . \
strlen( $results_of_the_calculations );
echo PHP_EOL;
if ( memory_get_usage() >= 20 * 1024 * 1024 )
{
echo PHP_EOL . 'Process recording: Normal break.' . PHP_EOL;
break;
}
if ( memory_get_usage() >= $memory_limit )
{
echo PHP_EOL . 'Process recording: Memory limit reached. Save calculated \
results so far.' . PHP_EOL;
$results_of_the_calculations = null;
}
$last_memory_usage = memory_get_usage();
}
echo PHP_EOL;
$results_of_the_calculations = null;
echo 'Process recording: Calculations completed. Results are saved.' . PHP_EOL . \
PHP_EOL;
echo 'Processing time: ' . elapsed_time( $measuring_point_of_time ) . ' seconds.' \
. PHP_EOL . PHP_EOL;
//-------------------------------------------------
// FUNCTIONS
//-------------------------------------------------
function elapsed_time( $measuring_point_of_time )
{
return number_format( microtime( true ) - $measuring_point_of_time, 3 );
}
function human_readable_file_size( precision = 2 )
{
$label = array( 'Bytes', 'kByte', 'MByte', 'GByte', 'TByte', 'PByte', \
'EByte', 'ZByte', 'YByte' );
return file_size / pow( 1024, ( file_size, 1024 ) ) ) ), label[ $index ] : '0 \
Bytes'; }
function conversion_back_to_bytes( $value )
{
value, -1 ) );
if ( value * 1024; endif;
if ( value * 1048576; endif;
if ( value * 1073741824; endif;
return $value;
}
?>
Expected result:
----------------
The "memory_get_usage" function must continually display the current memory usage to \
effectively operate at the memory limit.
Actual result:
--------------
C:\Users\User\Desktop\php-on-limit.php [PHP:7.3.4][PID:1224]
memory_limit -- 16 MByte -- defined limit
memory_limit -- 6.4 MByte -- usable limit
memory_allocated -- 2 MByte -- memory_used -- 410408
memory_allocated -- 2 MByte -- memory_used -- 411688 -- data_length -- 1024
memory_allocated -- 2 MByte -- memory_used -- 412968 -- data_length -- 2048
memory_allocated -- 2 MByte -- memory_used -- 414504 -- data_length -- 3072
memory_allocated -- 2 MByte -- memory_used -- 418600 -- data_length -- 4096
Process recording: Memory function has not changed. currently_memory_usage and \
last_memory_usage are 418520
Process recording: Calculations completed. Results are saved.
Processing time: 0.001 seconds.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=77879&edit=1
[Attachment #3 (text/html)]
what's the meaning £¿ speak Chinese<DIV style="COLOR: #000"><DIV \
style="PADDING-RIGHT: 0px; PADDING-LEFT: 0px; FONT-SIZE: 12px; PADDING-BOTTOM: 2px; \
PADDING-TOP: 2px; FONT-FAMILY: Arial \
Narrow">------------------ ÔʼÓʼþ ------------------</DIV><DIV \
style="PADDING-RIGHT: 8px; PADDING-LEFT: 8px; FONT-SIZE: 12px; BACKGROUND: #efefef; \
PADDING-BOTTOM: 8px; PADDING-TOP: \
8px"><DIV><B>·¢¼þÈË:</B> "nikic"<nikic@php.net><wbr/></DIV><DIV><B>·¢ËÍʱ¼ä:</B> 2019Äê4Ô \
12ÈÕ(ÐÇÆÚÎå) Ï Îç3:48</DIV><DIV><B>ÊÕ¼þÈË:</B> "php-bugs"<php-bugs@l \
ists.php.net>;"php-qa"<php-qa@lists.php.net>;</DIV><DIV><B>Ö÷Ìâ:</B> Bug \
#77879 [Opn->Nab]: Usable memory</DIV></DIV></DIV>Edit report at \
https://bugs.php.net/bug.php?id=77879&edit=1<br/><br/> ID: \
77879<br/> Updated by: \
nikic@php.net<br/> Reported by: xxalfa \
at gmail dot com<br/> Summary: \
Usable memory<br/>-Status: \
Open<br/>+Status: \
Not a bug<br/> Type: \
Bug<br/> Package: \
Testing related<br/> Operating System: Windows<br/> PHP \
Version: 7.3.4<br/> Block user \
comment: N<br/> Private report: N<br/><br/> New \
Comment:<br/><br/>Memory allocations are restricted to certain sizes for performance \
reasons. Small allocations are rounded up the next largest bin size. When the memory \
is reallocated with a size that still fits within the same bin, the reallocation is \
performed in-place and the reported memory usage will not \
change.<br/><br/><br/>Previous \
Comments:<br/>------------------------------------------------------------------------<br/>[2019-04-12 \
03:06:55] requinix@php.net<br/><br/>No, the memory does not increase by 1024 each \
time. It increases by whatever amount PHP allocates in order to expand the string by \
another 1024 bytes. As your output shows, the last step it went up by 4096 - enough \
for approximately 4 increases.<br/><br/>Should it have only allocated 1k? Is it bad \
that PHP is reserving more memory than the precise amount it needs at that given \
moment?<br/><br/>------------------------------------------------------------------------<br/>[2019-04-12 \
02:58:35] xxalfa at gmail dot com<br/><br/>The script executes successfully because \
it has detected because the level of memory has not changed. However, the level \
increases by 1024 per cycle, if the function were to work properly, the script would \
continue to work. That's why it's a \
bug.<br/><br/>------------------------------------------------------------------------<br/>[2019-04-12 \
02:26:32] requinix@php.net<br/><br/>Your script is quitting because PHP didn't \
need to allocate more memory to handle another 1k characters. Why is that a \
bug?<br/><br/>------------------------------------------------------------------------<br/>[2019-04-12 \
01:48:30] xxalfa at gmail dot com<br/><br/>Description:<br/>------------<br/>The \
following script fills the memory with pointless data. Now the problem: From one \
point, the function "memory_get_usage" returns the same value, although the \
level has changed. This is important if you want to process data and save it only \
when a certain number of results have been generated. The second problem: Why are \
only 40% usable?<br/><br/>Test \
script:<br/>---------------<br/><?php<br/><br/> // \
C:\Users\User\Desktop\php-on-limit.cmd<br/> // @echo \
off<br/> // title PHP Development Server<br/> // \
cd "%cd%"<br/> // rem "C:\php\php.exe" \
"php-on-limit.php"<br/> // "C:\php\php.exe" \
"-d memory_limit=16M" "php-on-limit.php"<br/> \
// pause<br/><br/> // C:\Users\User\Desktop\php-on-limit.php \
[PHP:7.3.3][PID:6336]<br/><br/> \
//-------------------------------------------------<br/> // \
HEAD<br/> \
//-------------------------------------------------<br/><br/> \
declare( strict_types = 1 );<br/><br/> header( \
'Content-Type:text/plain' );<br/><br/> error_reporting( \
E_ALL );<br/><br/> ini_set( 'display_errors', '1' \
);<br/><br/> ini_set( 'html_errors', '0' \
);<br/><br/> define( 'CORE_DIR', dirname( __FILE__ ) . \
DIRECTORY_SEPARATOR );<br/><br/> isset( $argv ) or trigger_error( \
'This is a command terminal application.', E_USER_ERROR \
);<br/><br/> echo __FILE__ . ' [PHP:' . phpversion() . \
'][PID:' . getmypid() . ']' . PHP_EOL . \
PHP_EOL;<br/><br/> \
//-------------------------------------------------<br/> // \
CODE<br/> \
//-------------------------------------------------<br/><br/> \
$measuring_point_of_time = microtime( true );<br/><br/> \
$memory_limit = conversion_back_to_bytes( ini_get( 'memory_limit' ) \
);<br/><br/> echo 'memory_limit -- ' . \
human_readable_file_size( $memory_limit ) . ' -- defined limit' . \
PHP_EOL;<br/><br/> // $memory_limit *= 0.48; // 48% of 128M can \
only be used<br/><br/> // $memory_limit *= 0.47; // 47% of 64M can \
only be used<br/><br/> $memory_limit *= 0.40; // 40% of 16M can \
only be used<br/><br/> // If the 40% is exceeded, it comes to a \
fatal error, which is not desirable.<br/><br/> // Fatal error: \
Allowed memory size of 16 MByte exhausted (tried to allocate 6 \
MByte).<br/><br/> echo 'memory_limit -- ' . \
human_readable_file_size( $memory_limit ) . ' -- usable limit' . \
PHP_EOL;<br/><br/> echo 'memory_allocated -- ' . \
human_readable_file_size( memory_get_usage( true ) ) . ' -- memory_used -- ' \
. memory_get_usage() . PHP_EOL;<br/><br/> \
$something_has_to_be_calculated = true;<br/><br/> \
$results_of_the_calculations = null;<br/><br/> $last_memory_usage = \
memory_get_usage();<br/><br/> while ( \
$something_has_to_be_calculated )<br/> \
{<br/> $results_of_the_calculations .= \
str_repeat( '1', 1024 );<br/><br/> \
$currently_memory_usage = \
memory_get_usage();<br/><br/> if ( \
last_memory_usage )<br/> \
{<br/> echo PHP_EOL \
. 'Process recording: Memory function has not changed. currently_memory_usage and \
last_memory_usage are ' . $currently_memory_usage . \
PHP_EOL;<br/><br/> \
break;<br/> \
}<br/><br/> // echo chr( 0xD \
);<br/><br/> echo 'memory_allocated -- \
' . human_readable_file_size( memory_get_usage( true ) ) . ' -- memory_used \
-- ' . memory_get_usage() . ' -- data_length -- ' . strlen( \
$results_of_the_calculations );<br/><br/> \
echo PHP_EOL;<br/><br/> if ( \
memory_get_usage() >= 20 * 1024 * 1024 \
)<br/> \
{<br/> echo PHP_EOL \
. 'Process recording: Normal break.' . \
PHP_EOL;<br/><br/> \
break;<br/> \
}<br/><br/> if ( memory_get_usage() >= \
$memory_limit )<br/> \
{<br/> echo PHP_EOL \
. 'Process recording: Memory limit reached. Save calculated results so far.' \
. PHP_EOL;<br/><br/> \
$results_of_the_calculations = null;<br/> \
}<br/><br/> $last_memory_usage = \
memory_get_usage();<br/> }<br/><br/> echo \
PHP_EOL;<br/><br/> $results_of_the_calculations = \
null;<br/><br/> echo 'Process recording: Calculations \
completed. Results are saved.' . PHP_EOL . PHP_EOL;<br/><br/> \
echo 'Processing time: ' . elapsed_time( $measuring_point_of_time ) . ' \
seconds.' . PHP_EOL . PHP_EOL;<br/><br/> \
//-------------------------------------------------<br/> // \
FUNCTIONS<br/> \
//-------------------------------------------------<br/><br/> \
function elapsed_time( $measuring_point_of_time )<br/> \
{<br/> return number_format( microtime( \
true ) - $measuring_point_of_time, 3 );<br/> \
}<br/><br/> function human_readable_file_size( precision = 2 \
)<br/> {<br/> $label = \
array( 'Bytes', 'kByte', 'MByte', 'GByte', \
'TByte', 'PByte', 'EByte', 'ZByte', 'YByte' \
);<br/><br/> return file_size / pow( 1024, \
( file_size, 1024 ) ) ) ), label[ $index ] : '0 \
Bytes';<br/> }<br/><br/> function \
conversion_back_to_bytes( $value )<br/> \
{<br/> value, -1 ) \
);<br/><br/> if ( value * 1024; \
endif;<br/><br/> if ( value * 1048576; \
endif;<br/><br/> if ( value * 1073741824; \
endif;<br/><br/> return \
$value;<br/> }<br/><br/>?><br/><br/>Expected \
result:<br/>----------------<br/>The "memory_get_usage" function must \
continually display the current memory usage to effectively operate at the memory \
limit.<br/><br/>Actual \
result:<br/>--------------<br/>C:\Users\User\Desktop\php-on-limit.php \
[PHP:7.3.4][PID:1224]<br/><br/>memory_limit -- 16 MByte -- defined \
limit<br/>memory_limit -- 6.4 MByte -- usable limit<br/>memory_allocated -- 2 MByte \
-- memory_used -- 410408<br/>memory_allocated -- 2 MByte -- memory_used -- 411688 -- \
data_length -- 1024<br/>memory_allocated -- 2 MByte -- memory_used -- 412968 -- \
data_length -- 2048<br/>memory_allocated -- 2 MByte -- memory_used -- 414504 -- \
data_length -- 3072<br/>memory_allocated -- 2 MByte -- memory_used -- 418600 -- \
data_length -- 4096<br/><br/>Process recording: Memory function has not changed. \
currently_memory_usage and last_memory_usage are 418520<br/><br/>Process recording: \
Calculations completed. Results are saved.<br/><br/>Processing time: 0.001 \
seconds.<br/><br/><br/>------------------------------------------------------------------------<br/><br/><br/><br/>--<br/>Edit \
this bug report at https://bugs.php.net/bug.php?id=77879&edit=1<br/>
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