cpuidle: fix 100% C0 statistics regression
authorVenki Pallipadi <venkatesh.pallipadi@intel.com>
Fri, 29 Feb 2008 18:24:32 +0000 (10:24 -0800)
committerLen Brown <len.brown@intel.com>
Wed, 26 Mar 2008 04:58:19 +0000 (00:58 -0400)
commit8e92b6605da989c0aa8ff7e33306f36f0efd957c
treeaafbc4628b907f4134ad91db9b160941f246dfcf
parent8b78cf602fd3bd97c0080edd22fe8fd5d0fa7832
cpuidle: fix 100% C0 statistics regression

commit 9b12e18cdc1553de62d931e73443c806347cd974
'ACPI: cpuidle: Support C1 idle time accounting'
was implicated in a 100% C0 idle regression.
http://bugzilla.kernel.org/show_bug.cgi?id=10076

It pointed out a potential problem where the menu governor
may get confused by the C-state residency time from poll
idle or C1 idle, where this timing info is not accurate.
This inaccuracy is due to interrupts being handled
before we account for C-state exit.

Do not mark TIME_VALID for CO poll state.
Mark C1 time as valid only with the MWAIT (CSTATE_FFH) entry method.

This makes governors use the timing information only when it is correct and
eliminates any wrong policy decisions that may result from invalid timing
information.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
drivers/acpi/processor_idle.c
drivers/cpuidle/cpuidle.c