tree 573e7538a7cf45fdbee7f9a33626faf9c5502bd4
parent 8005c49d9aea74d382f474ce11afbbc7d7130bec
author Rik van Riel <riel@redhat.com> 1446590057 -0500
committer Rafael J. Wysocki <rafael.j.wysocki@intel.com> 1447723464 +0100

cpuidle,x86: increase forced cut-off for polling to 20us

The cpuidle menu governor has a forced cut-off for polling at 5us,
in order to deal with firmware that gives the OS bad information
on cpuidle states, leading to the system spending way too much time
in polling.

However, at least one x86 CPU family (Atom) has chips that have
a 20us break-even point for C1. Forcing the polling cut-off to
less than that wastes performance and power.

Increase the polling cut-off to 20us.

Systems with a lower C1 latency will be found in the states table by
the menu governor, which will pick those states as appropriate.

Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>