Re: [RFC 00/13] x86/mm: PCID and INVPCID

From: Linus Torvalds
Date: Fri Jan 08 2016 - 18:31:11 EST

On Fri, Jan 8, 2016 at 3:15 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
> Please play around and suggest (and run?) good benchmarks. It seems
> to save around 100ns on cross-process context switches for me.

Interesting. There was reportedly (I never saw it) a test-patch to use
pcids inside of Intel a couple of years ago, and it never got outside
because it didn't make a difference.

Either things have changed (newer hardware with more pcids perhaps?)
or you did a better job at it.