These instructions are only available on more recent CPUs (MWAITX
on AMD since around 2015 or so, TPAUSE on Intel since around 2020.)
They allow idly waiting on the TSC even when interrupts are
disabled.
Most hypervisors do not have these available (KVM does provide
them, though not on all configurations), but on bare metal this
should make a nice difference to KDL power consumption: I tested
with a Ryzen 3700X, according to my UPS (so including monitor
and peripherals) the system used ~106 W at idle, 160 W in KDL
before this patch, and 125 W in KDL after it.
Change-Id: Id7a22ecd33f3fc005b2c312f945dc3cd364e96fa
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9604
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>
Augustin Cavalier
fb6c279a24