Re: minute performance gain

Jon Parise wrote:

On Sun, Oct 17, 2004 at 02:05:15PM -0400, Greg Beaver wrote:

I took the register_shutdown_function and moved it to the PEAR class constructor, inside the code that checks for destructors, and found a miniscule performance gain. Zend IDE's profiler reported that the time it takes to run 'PEAR.php'; decreased from .35 ms to .28 ms. By far the most significant performance hit comes from the require_once call, which leads me to believe that even using PEAR_Exception would do nothing to improve performance unless you put everything in 1 big-ass file. :)

To be fair, you only see this performance gain when no destructor is exists (and register_shutdown_function() is not called), yes?

Yes, but the majority of classes that extend PEAR don't have a destructor. Notable exceptions to this rule are Archive_Tar and PEAR_Common, and I guess MDB :). DB_common, for instance, does not define a destructor, and neither does PEAR_Error - the two most commonly used classes that extend PEAR. Also note that PEAR_Error does not call PEAR::PEAR(), so the destructor check is never performed. Also, even though PEAR defines _PEAR, note the code in PEAR::PEAR():

        while ($classname && strcasecmp($classname, "pear")) {
            $destructor = "_$classname";
            if (method_exists($this, $destructor)) {
                global $_PEAR_destructor_object_list;
                $_PEAR_destructor_object_list[] = &$this;
                static $registered = false;
                if (!$registered) {
                    register_shutdown_function("_PEAR_call_destructors");
                    $registered = true;
                }
                break;
            } else {
                $classname = get_parent_class($classname);
            }
        }

In English, this code will cycle through the parent classes until it finds a destructor or the class is PEAR - the _PEAR destructor is never registered. Greg