NVIDIA Senior Software Engineer interview questions

I have been interviewing for the past 4 months for Nvidia and I think after having positive feedback for a few positions I wasn't considered for any roles. This is totally frustrating  with last minute emails on cancelling the interview or finding another candidate. I think these guys are playing with candidates. The time taken here for each interview was close to 3 weeks. I have been interviewing for the past 4 months with 8 rounds and this kind of interview process is not helping either nvidia or myself nor you guys. It's really frustrating. It is such a waste of time when the company hiring process is not well defined. You need to respect the talent and people around the world. I know you guys crave for the best talent out there but it's not all about talent. It's about respecting interviewers too and their time, if you guys are looking for so much talent then why don't I see one PHD degree interviewer.  I would suggest to people here to accept other company offers that you guys get don't wait for nvidia. Let them keep craving for talent.