The two AsiaBSD papers linked from the post are good for more detail. I was a little surprised they had to hack sendfile to do the crypto in the kernel in order to get the throughput they're used to with http, but the reasons are explained in the papers.

However, I'm quite surprised Netflix went with Intel's ISA-L library for AES-GCM given Intel's perf gains were so very marginal compared to BoringSSL. I would have gone with the library that had more eyeballs on it, and in general I'd give Google the edge over writing solid, secure code than I would Intel.