I applied for the job while I was in school, and HR contacted me.

I arranged for a phone interview with the hiring manager. He was very polite and asked me to mail him a "Cycle in Linked List" solution.

The on-site interview was long and rigorous. It involved about 4 engineers, 1 manager, 1 VP, and 1 HR representative.

Most questions were around concurrent systems, including race conditions, deadlocks, livelocks, semaphores, and operating system internals.

The newer members asked about bit-twiddling hacks (please go through Stanford's bit-twiddling hacks; you won't regret it :-)).

Cache coherence algorithms between I/O and CPU.

An interviewer described a complex race condition involving OS code and GPU work submission. They asked me to fix it using a register and no extra buffer.