This is a note to let you know that I've just added the patch titled
Revert "cpuidle: Quickly notice prediction failure in general case"
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-cpuidle-quickly-notice-prediction-failure-in-general-case.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 228b30234f258a193317874854eee1ca7807186e Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Date: Sat, 27 Jul 2013 01:13:26 +0200
Subject: Revert "cpuidle: Quickly notice prediction failure in general case"
From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
commit 228b30234f258a193317874854eee1ca7807186e upstream.
Revert commit e11538d1 (cpuidle: Quickly notice prediction failure in
general case), since it depends on commit 69a37be (cpuidle: Quickly
notice prediction failure for repeat mode) that has been identified
as the source of a significant performance regression in v3.8 and
later.
Requested-by: Jeremy Eder <jeder@xxxxxxxxxx>
Tested-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/cpuidle/governors/menu.c | 35 +----------------------------------
1 file changed, 1 insertion(+), 34 deletions(-)
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -34,7 +34,7 @@
static DEFINE_PER_CPU(struct hrtimer, menu_hrtimer);
static DEFINE_PER_CPU(int, hrtimer_status);
/* menu hrtimer mode */
-enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT, MENU_HRTIMER_GENERAL};
+enum {MENU_HRTIMER_STOP, MENU_HRTIMER_REPEAT};
/*
* Concepts and ideas behind the menu governor
@@ -116,13 +116,6 @@ enum {MENU_HRTIMER_STOP, MENU_HRTIMER_RE
*
*/
-/*
- * The C-state residency is so long that is is worthwhile to exit
- * from the shallow C-state and re-enter into a deeper C-state.
- */
-static unsigned int perfect_cstate_ms __read_mostly = 30;
-module_param(perfect_cstate_ms, uint, 0000);
-
struct menu_device {
int last_state_idx;
int needs_update;
@@ -223,16 +216,6 @@ EXPORT_SYMBOL_GPL(menu_hrtimer_cancel);
static enum hrtimer_restart menu_hrtimer_notify(struct hrtimer *hrtimer)
{
int cpu = smp_processor_id();
- struct menu_device *data = &per_cpu(menu_devices, cpu);
-
- /* In general case, the expected residency is much larger than
- * deepest C-state target residency, but prediction logic still
- * predicts a small predicted residency, so the prediction
- * history is totally broken if the timer is triggered.
- * So reset the correction factor.
- */
- if (per_cpu(hrtimer_status, cpu) == MENU_HRTIMER_GENERAL)
- data->correction_factor[data->bucket] = RESOLUTION * DECAY;
per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_STOP;
@@ -389,7 +372,6 @@ static int menu_select(struct cpuidle_dr
/* not deepest C-state chosen for low predicted residency */
if (low_predicted) {
unsigned int timer_us = 0;
- unsigned int perfect_us = 0;
/*
* Set a timer to detect whether this sleep is much
@@ -400,28 +382,13 @@ static int menu_select(struct cpuidle_dr
*/
timer_us = 2 * (data->predicted_us + MAX_DEVIATION);
- perfect_us = perfect_cstate_ms * 1000;
-
if (repeat && (4 * timer_us < data->expected_us)) {
RCU_NONIDLE(hrtimer_start(hrtmr,
ns_to_ktime(1000 * timer_us),
HRTIMER_MODE_REL_PINNED));
/* In repeat case, menu hrtimer is started */
per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_REPEAT;
- } else if (perfect_us < data->expected_us) {
- /*
- * The next timer is long. This could be because
- * we did not make a useful prediction.
- * In that case, it makes sense to re-enter
- * into a deeper C-state after some time.
- */
- RCU_NONIDLE(hrtimer_start(hrtmr,
- ns_to_ktime(1000 * timer_us),
- HRTIMER_MODE_REL_PINNED));
- /* In general case, menu hrtimer is started */
- per_cpu(hrtimer_status, cpu) = MENU_HRTIMER_GENERAL;
}
-
}
return data->last_state_idx;
Patches currently in stable-queue which might be from rafael.j.wysocki@xxxxxxxxx are
queue-3.10/acpi-battery-fix-parsing-_bix-return-value.patch
queue-3.10/revert-cpuidle-quickly-notice-prediction-failure-in-general-case.patch
queue-3.10/revert-cpuidle-quickly-notice-prediction-failure-for-repeat-mode.patch
queue-3.10/cpufreq-fix-cpufreq-driver-module-refcount-balance-after-suspend-resume.patch
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