Improve PHP-Workerman performance (#4123)

frameworks/PHP/workerman/server.php

@@ -12,13 +12,16 @@ function get_processor_cores_number() {
 }
 
 $http_worker = new Worker('http://0.0.0.0:8080');
-$http_worker->count = get_processor_cores_number() * 2 || 8;
-$http_worker->onMessage = function($connection, $data)
+$http_worker->count = (get_processor_cores_number() * 2) || 64;
+$http_worker->onWorkerStart = function()
 {
+  global $pdo;
   $pdo = new PDO('mysql:host=tfb-database;dbname=hello_world;charset=utf8',
-  'benchmarkdbuser', 'benchmarkdbpass', array(
-    PDO::ATTR_PERSISTENT => true
-  ));
+  'benchmarkdbuser', 'benchmarkdbpass');
+};
+$http_worker->onMessage = function($connection, $data)
+{
+  global $pdo;
   $base = $_SERVER['REQUEST_URI'];
   $question = strpos($base, '?');
   if ($question !== false) {