Transatlantic Ping Faster Than Sending a Pixel to the Screen
John Carmack (via John Siracusa):
To measure display latency, I have a small program that sits in a spin loop polling a game controller, doing a clear to a different color and swapping buffers whenever a button is pressed. I video record showing both the game controller and the screen with a 240 fps camera, then count the number of frames between the button being pressed and the screen starting to show a change.
I think the lesson here is that intuition about performance bottlenecks is often wrong.
