i find http://fuelphp.com/forums/topics/view/5945
but if i want to set profiling , not change config.php how can i do?
sometimes i need debug by admin,but not all users.
also cache_lifetime, caching....
You can not alter certain config values at runtime, as they are used in the FuelPHP boot process. Profiling is such a setting.
You will have to add code to your config file to determine the value to return instead of returning a fixed value.
Config files are normal PHP files, so you can add to it what you want.
// this works find in a config file
$loggedin = \Auth::check();
return array(
'setting' => $loggedin ? 'Yes' : 'No',
);