Bug #68624 [NEW]: by reference arrays slow down within the function as the array grows

From: lindsay at notion dot co Operating system: linux and mac PHP version: 5.6.3 Package: Performance problem Bug Type: Bug Bug description:by reference arrays slow down within the function as the array grows Description: ------------ Within a function, if an array is passed in by reference, operations on the array get slow within the function as the array grows. In this example, is_array() gets much slower. Here is output from the example script with and with out the array variable being passed as reference. walk_array 10000 0.039294004440308 20000 0.031054973602295 30000 0.026264190673828 40000 0.025592803955078 50000 0.026119947433472 60000 0.025648832321167 70000 0.026489973068237 80000 0.023653984069824 90000 0.028777122497559 walk_array_by_reference 10000 1.7504909038544 20000 6.3624141216278 30000 14.600469827652 40000 28.24251294136 50000 37.910901069641 60000 46.824372053146 70000 60.680932044983 80000 71.826647043228 90000 78.522189855576 Tested against 'PHP 5.5.14-2+deb.sury.org~precise+1 (cli)' and 'PHP 5.6.2 (cli)' Test script: --------------- <?php define('LOOP_COUNT', 100000); define('LOOP_PRINT', 10000); $array = []; walk_array($array); walk_array_by_reference($array); function walk_array($array) { echo 'walk_array' . PHP_EOL; $timer = microtime(true); for ($i = 1; $i < LOOP_COUNT; $i++) { if ($i % LOOP_PRINT == 0) { echo $i . ' ' . (microtime(true) - $timer) . PHP_EOL; $timer = microtime(true); } $array[$i] = 1; if (is_array($array)) {} } } function walk_array_by_reference(&$array) { echo 'walk_array_by_reference' . PHP_EOL; $timer = microtime(true); for ($i = 1; $i < LOOP_COUNT; $i++) { if ($i % LOOP_PRINT == 0) { echo $i . ' ' . (microtime(true) - $timer) . PHP_EOL; $timer = microtime(true); } $array[$i] = 1; if (is_array($array)) {} } } -- Edit bug report at https://bugs.php.net/bug.php?id=68624&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=68624&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=68624&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=68624&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=68624&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=68624&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=68624&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=68624&r=needscript Try newer version: https://bugs.php.net/fix.php?id=68624&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=68624&r=support Expected behavior: https://bugs.php.net/fix.php?id=68624&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=68624&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=68624&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=68624&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=68624&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=68624&r=dst IIS Stability: https://bugs.php.net/fix.php?id=68624&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=68624&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=68624&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=68624&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=68624&r=mysqlcfg