Re: [RFC PATCH 2/4] x86, mwaitt: introduce mwaitx idle with a configurable timer

Andy Lutomirski
2015-05-21T05:48:34Z

On May 20, 2015 6:34 PM, "Andy Lutomirski" <luto@kernel.org> wrote:
> If we did that *and* we had a non-crappy mwaitx, then we could apply an optimization: when going idle, we could turn off the TSC deadline timer and use mwaitx instead. This would about an interrupt if the event that wakes us is our timer.
>

Hey, Intel, want to document your secret "Timed MWAIT" feature? It
causes a transition to C0 when the deadline expires (see 4.2.4 of the
Desktop 4th Generation Intel Core Processor Family Datasheet Volume 1,
order number 328897-001) and it even has an erratum (HSD63 / BDM32),
but the instruction itself doesn't appear to be documented.

--Andy