Req #73887 [NEW]: Improve realpath cache eviction strategy

From: maggus dot staab at gmail dot com Operating system: PHP version: 7.1.0 Package: Performance problem Bug Type: Feature/Change Request Bug description:Improve realpath cache eviction strategy Description: ------------ We recently changed the default realpath cache size as we realized that the default size is too small, see https://github.com/php/php-src/pull/2271. After a closer look into the realpath cache impl krakjoe and bwoebi mentioned, that cache eviction of this cache is very suboptiomal. Cache items are only evicted after a find. Entries never get evicted when no longer used. Php is forced todo some expensive file-io operations when the realpath cache cannot deliver the information from memory. This is especially expensive for long running php scripts, like cli based processes/webservers/... A first improvement would be some kind garbage collection, which isnt bound to a previous find. 2nd the cache could benefit from some kind of LRU cache. 3rd krakjoe mentioned that it might be sometimes usefull to share the cache information in shm. Related discussion: http://chat.stackoverflow.com/transcript/message/34952738#34952738 Starting 5:32 PM -- Edit bug report at https://bugs.php.net/bug.php?id=73887&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=73887&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=73887&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=73887&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=73887&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=73887&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=73887&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=73887&r=needscript Try newer version: https://bugs.php.net/fix.php?id=73887&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=73887&r=support Expected behavior: https://bugs.php.net/fix.php?id=73887&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=73887&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=73887&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=73887&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=73887&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=73887&r=dst IIS Stability: https://bugs.php.net/fix.php?id=73887&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=73887&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=73887&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=73887&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=73887&r=mysqlcfg