Oh what a mistake.. Happens when coding 12pm(at my timezone).
I just added
gui::IGUIFont* font = device->getGUIEnvironment()->getBuiltInFont();
before loop and
core::stringw str = L"FPS @ ";
str += (s32)driver->getFPS();
if (font)
font->draw(str.c_str(),
core::rect<s32>(130,10,300,50),
video ...