I applied through college or university. The process took 1 day. I interviewed at National Instruments (New Delhi) in Sep 2013
Interview
first 30 min test is done which includes very difficult puzzles and technical questons as well.....followed by gd and selection is on the basis of both.
I applied through a staffing agency. The process took 1 day. I interviewed at National Instruments (Bengaluru) in Aug 2014
Interview
It was a long process. I had 7 rounds, with Sales, HR and Technical mixed. It is a thorough process. Your team and Manager will take the interview. Very selective, so prepare well.