How do I measure the page load time in a CI application that is using Smarty? Right now, I have put benchmark points at the beginning and end of the index() method, but that only measures the execution time of the method, right? I want to know how long it take to fully render a page.
I would point you to the Codeigniter Profiler
When used in conjunction to the Benchmarking, it gives you fairly detailed results, this should be exactly what you are looking for.
make sure you adjust your benchmark points to conform to the profiler specs though.