Children      Self  Command  Shared Object        Symbol                                                   
+   99.17%     0.00%  mysqld   libpthread-2.17.so   [.] start_thread                                         
+   99.17%     0.00%  mysqld   mysqld               [.] pfs_spawn_thread                                     
+   99.17%     0.00%  mysqld   mysqld               [.] handle_connection                                    
+   99.17%     0.00%  mysqld   mysqld               [.] do_command                                           
+   99.17%     0.00%  mysqld   mysqld               [.] dispatch_command

上面的执行顺序是从上到下处理，还是从下往上处理呢？？