K 10
svn:author
V 6
adrian
K 8
svn:date
V 27
2015-04-27T19:18:51.138357Z
K 7
svn:log
V 599
Drop the default for performance_cx_lowest (ie, what to use when AC is connected) to ACPI C2.

ACPI C3 ends up doing a lot more work before entering sleep, some of which
requires grabbing a global ACPI hardware serialising mutex.

Because of this, the more CPU cores you have, the more that lock contends
under load, reaching close to the #1 lock contention (after VM, which is being
worked on.)

Tested:

* Sandy bridge Xeon, 2 socket * 8 core
* Ivy bridge Xeon v2, 2 socket * 8 core
* Westmere-EX, 4 socket * 10 core
* Ivybridge desktop
* Sandybridge mobile
* Ivybridge mobile

MFC after:	2 weeks

END