Расширение APCu не поддерживается CMS Bitrix:
bitrix\modules\perfmon\classes\general\measure.php
<?php
public static function GetAllAccelerators()
{
$result = array();
if (function_exists('accelerator_reset'))
$result[] = new CPerfAccelZend;
if (extension_loaded('apc') && !extension_loaded('apcu'))
$result[] = new CPerfAccelAPC;
if (extension_loaded('xcache'))
$result[] = new CPerfAccelXCache;
// Wincache removed opcode cache since 2.0.0.1
// https://pecl.php.net/package-changelog.php?package=WinCache&release=2.0.0.1
if (extension_loaded('wincache') && function_exists('wincache_ocache_meminfo'))
$result[] = new CPerfAccelWinCache;
if (extension_loaded('Zend OPcache'))
$result[] = new CPerfAccelZendOpCache;
return $result;
}