From: Venki Pallipadi <venkatesh.pallipadi@xxxxxxxxx> 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@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/processor_idle.c | 4 +++- drivers/cpuidle/cpuidle.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 1468f1e..788da97 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; diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index d42deb3..fc555a9 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -224,7 +224,7 @@ static void poll_idle_init(struct cpuidle_device *dev) state->exit_latency = 0; state->target_residency = 0; state->power_usage = -1; - state->flags = CPUIDLE_FLAG_POLL | CPUIDLE_FLAG_TIME_VALID; + state->flags = CPUIDLE_FLAG_POLL; state->enter = poll_idle; } #else -- 1.5.5.rc1.6.g5cc8f -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
