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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2008-02-29 10:24:32 -0800
committerLen Brown <len.brown@intel.com>2008-03-26 00:58:19 -0400
commit8e92b6605da989c0aa8ff7e33306f36f0efd957c (patch)
treeaafbc4628b907f4134ad91db9b160941f246dfcf /drivers/acpi
parent8b78cf602fd3bd97c0080edd22fe8fd5d0fa7832 (diff)
downloadlinux-8e92b6605da989c0aa8ff7e33306f36f0efd957c.tar.bz2
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>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_idle.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 1468f1e92cac..788da9781f80 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1693,7 +1693,9 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr)
switch (cx->type) {
case ACPI_STATE_C1:
state->flags |= CPUIDLE_FLAG_SHALLOW;
- state->flags |= CPUIDLE_FLAG_TIME_VALID;
+ if (cx->entry_method == ACPI_CSTATE_FFH)
+ state->flags |= CPUIDLE_FLAG_TIME_VALID;
+
state->enter = acpi_idle_enter_c1;
dev->safe_state = state;
break;