linux-moblin: Add 2.6.31.5

Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

1 files changed, 407 insertions, 0 deletions

diff --git a/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-cpuidle.patch b/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-cpuidle.patch
new file mode 100644
index 000000000..ef930b76d
--- /dev/null
+++ b/meta-moblin/packages/linux/linux-moblin-2.6.31.5/linux-2.6.32-cpuidle.patch
@@ -0,0 +1,407 @@
+From f890417fc5dc4450e1dab69d7a870d6e706825a5 Mon Sep 17 00:00:00 2001
+From: Arjan van de Ven <arjan@linux.intel.com>
+Date: Sun, 20 Sep 2009 08:45:07 +0200
+Subject: [PATCH] cpuidle: Fix the menu governor to boost IO performance
+
+Fix the menu idle governor which balances power savings, energy efficiency
+and performance impact.
+
+The reason for a reworked governor is that there have been serious
+performance issues reported with the existing code on Nehalem server
+systems.
+
+To show this I'm sure Andrew wants to see benchmark results:
+(benchmark is "fio", "no cstates" is using "idle=poll")
+
+		no cstates	current linux	new algorithm
+1 disk		107 Mb/s	85 Mb/s		105 Mb/s
+2 disks		215 Mb/s	123 Mb/s	209 Mb/s
+12 disks	590 Mb/s	320 Mb/s	585 Mb/s
+
+In various power benchmark measurements, no degredation was found by our
+measurement&diagnostics team.  Obviously a small percentage more power
+was used in the "fio" benchmark, due to the much higher performance.
+
+While it would be a novel idea to describe the new algorithm in this
+commit message, I cheaped out and described it in comments in the code
+instead.
+
+[changes in v2: spelling fixes from akpm, review feedback,
+folded menu-tng into menu.c
+ changes in v3: use this_rq() as per akpm suggestion]
+
+Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
+Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+Cc: Len Brown <lenb@kernel.org>
+Acked-by: Ingo Molnar <mingo@elte.hu>
+Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+---
+ drivers/cpuidle/governors/menu.c |  251 ++++++++++++++++++++++++++++++++------
+ include/linux/sched.h            |    4 +
+ kernel/sched.c                   |   13 ++
+ 3 files changed, 229 insertions(+), 39 deletions(-)
+
+diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
+index f1df59f..9f3d775 100644
+--- a/drivers/cpuidle/governors/menu.c
++++ b/drivers/cpuidle/governors/menu.c
+@@ -2,8 +2,12 @@
+  * menu.c - the menu idle governor
+  *
+  * Copyright (C) 2006-2007 Adam Belay <abelay@novell.com>
++ * Copyright (C) 2009 Intel Corporation
++ * Author:
++ *        Arjan van de Ven <arjan@linux.intel.com>
+  *
+- * This code is licenced under the GPL.
++ * This code is licenced under the GPL version 2 as described
++ * in the COPYING file that acompanies the Linux Kernel.
+  */
+ 
+ #include <linux/kernel.h>
+@@ -13,20 +17,153 @@
+ #include <linux/ktime.h>
+ #include <linux/hrtimer.h>
+ #include <linux/tick.h>
++#include <linux/sched.h>
+ 
+-#define BREAK_FUZZ	4	/* 4 us */
+-#define PRED_HISTORY_PCT	50
++#define BUCKETS 12
++#define RESOLUTION 1024
++#define DECAY 4
++#define MAX_INTERESTING 50000
++
++/*
++ * Concepts and ideas behind the menu governor
++ *
++ * For the menu governor, there are 3 decision factors for picking a C
++ * state:
++ * 1) Energy break even point
++ * 2) Performance impact
++ * 3) Latency tolerance (from pmqos infrastructure)
++ * These these three factors are treated independently.
++ *
++ * Energy break even point
++ * -----------------------
++ * C state entry and exit have an energy cost, and a certain amount of time in
++ * the  C state is required to actually break even on this cost. CPUIDLE
++ * provides us this duration in the "target_residency" field. So all that we
++ * need is a good prediction of how long we'll be idle. Like the traditional
++ * menu governor, we start with the actual known "next timer event" time.
++ *
++ * Since there are other source of wakeups (interrupts for example) than
++ * the next timer event, this estimation is rather optimistic. To get a
++ * more realistic estimate, a correction factor is applied to the estimate,
++ * that is based on historic behavior. For example, if in the past the actual
++ * duration always was 50% of the next timer tick, the correction factor will
++ * be 0.5.
++ *
++ * menu uses a running average for this correction factor, however it uses a
++ * set of factors, not just a single factor. This stems from the realization
++ * that the ratio is dependent on the order of magnitude of the expected
++ * duration; if we expect 500 milliseconds of idle time the likelihood of
++ * getting an interrupt very early is much higher than if we expect 50 micro
++ * seconds of idle time. A second independent factor that has big impact on
++ * the actual factor is if there is (disk) IO outstanding or not.
++ * (as a special twist, we consider every sleep longer than 50 milliseconds
++ * as perfect; there are no power gains for sleeping longer than this)
++ *
++ * For these two reasons we keep an array of 12 independent factors, that gets
++ * indexed based on the magnitude of the expected duration as well as the
++ * "is IO outstanding" property.
++ *
++ * Limiting Performance Impact
++ * ---------------------------
++ * C states, especially those with large exit latencies, can have a real
++ * noticable impact on workloads, which is not acceptable for most sysadmins,
++ * and in addition, less performance has a power price of its own.
++ *
++ * As a general rule of thumb, menu assumes that the following heuristic
++ * holds:
++ *     The busier the system, the less impact of C states is acceptable
++ *
++ * This rule-of-thumb is implemented using a performance-multiplier:
++ * If the exit latency times the performance multiplier is longer than
++ * the predicted duration, the C state is not considered a candidate
++ * for selection due to a too high performance impact. So the higher
++ * this multiplier is, the longer we need to be idle to pick a deep C
++ * state, and thus the less likely a busy CPU will hit such a deep
++ * C state.
++ *
++ * Two factors are used in determing this multiplier:
++ * a value of 10 is added for each point of "per cpu load average" we have.
++ * a value of 5 points is added for each process that is waiting for
++ * IO on this CPU.
++ * (these values are experimentally determined)
++ *
++ * The load average factor gives a longer term (few seconds) input to the
++ * decision, while the iowait value gives a cpu local instantanious input.
++ * The iowait factor may look low, but realize that this is also already
++ * represented in the system load average.
++ *
++ */
+ 
+ struct menu_device {
+ 	int		last_state_idx;
+ 
+ 	unsigned int	expected_us;
+-	unsigned int	predicted_us;
+-	unsigned int    current_predicted_us;
+-	unsigned int	last_measured_us;
+-	unsigned int	elapsed_us;
++	u64		predicted_us;
++	unsigned int	measured_us;
++	unsigned int	exit_us;
++	unsigned int	bucket;
++	u64		correction_factor[BUCKETS];
+ };
+ 
++
++#define LOAD_INT(x) ((x) >> FSHIFT)
++#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
++
++static int get_loadavg(void)
++{
++	unsigned long this = this_cpu_load();
++
++
++	return LOAD_INT(this) * 10 + LOAD_FRAC(this) / 10;
++}
++
++static inline int which_bucket(unsigned int duration)
++{
++	int bucket = 0;
++
++	/*
++	 * We keep two groups of stats; one with no
++	 * IO pending, one without.
++	 * This allows us to calculate
++	 * E(duration)|iowait
++	 */
++	if (nr_iowait_cpu())
++		bucket = BUCKETS/2;
++
++	if (duration < 10)
++		return bucket;
++	if (duration < 100)
++		return bucket + 1;
++	if (duration < 1000)
++		return bucket + 2;
++	if (duration < 10000)
++		return bucket + 3;
++	if (duration < 100000)
++		return bucket + 4;
++	return bucket + 5;
++}
++
++/*
++ * Return a multiplier for the exit latency that is intended
++ * to take performance requirements into account.
++ * The more performance critical we estimate the system
++ * to be, the higher this multiplier, and thus the higher
++ * the barrier to go to an expensive C state.
++ */
++static inline int performance_multiplier(void)
++{
++	int mult = 1;
++
++	/* for higher loadavg, we are more reluctant */
++
++	mult += 2 * get_loadavg();
++
++	/* for IO wait tasks (per cpu!) we add 5x each */
++	mult += 10 * nr_iowait_cpu();
++
++	return mult;
++}
++
+ static DEFINE_PER_CPU(struct menu_device, menu_devices);
+ 
+ /**
+@@ -38,37 +175,59 @@ static int menu_select(struct cpuidle_device *dev)
+ 	struct menu_device *data = &__get_cpu_var(menu_devices);
+ 	int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
+ 	int i;
++	int multiplier;
++
++	data->last_state_idx = 0;
++	data->exit_us = 0;
+ 
+ 	/* Special case when user has set very strict latency requirement */
+-	if (unlikely(latency_req == 0)) {
+-		data->last_state_idx = 0;
++	if (unlikely(latency_req == 0))
+ 		return 0;
+-	}
+ 
+-	/* determine the expected residency time */
++	/* determine the expected residency time, round up */
+ 	data->expected_us =
+-		(u32) ktime_to_ns(tick_nohz_get_sleep_length()) / 1000;
++	    DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000);
++
++
++	data->bucket = which_bucket(data->expected_us);
++
++	multiplier = performance_multiplier();
++
++	/*
++	 * if the correction factor is 0 (eg first time init or cpu hotplug
++	 * etc), we actually want to start out with a unity factor.
++	 */
++	if (data->correction_factor[data->bucket] == 0)
++		data->correction_factor[data->bucket] = RESOLUTION * DECAY;
++
++	/* Make sure to round up for half microseconds */
++	data->predicted_us = DIV_ROUND_CLOSEST(
++		data->expected_us * data->correction_factor[data->bucket],
++		RESOLUTION * DECAY);
++
++	/*
++	 * We want to default to C1 (hlt), not to busy polling
++	 * unless the timer is happening really really soon.
++	 */
++	if (data->expected_us > 5)
++		data->last_state_idx = CPUIDLE_DRIVER_STATE_START;
+ 
+-	/* Recalculate predicted_us based on prediction_history_pct */
+-	data->predicted_us *= PRED_HISTORY_PCT;
+-	data->predicted_us += (100 - PRED_HISTORY_PCT) *
+-				data->current_predicted_us;
+-	data->predicted_us /= 100;
+ 
+ 	/* find the deepest idle state that satisfies our constraints */
+-	for (i = CPUIDLE_DRIVER_STATE_START + 1; i < dev->state_count; i++) {
++	for (i = CPUIDLE_DRIVER_STATE_START; i < dev->state_count; i++) {
+ 		struct cpuidle_state *s = &dev->states[i];
+ 
+-		if (s->target_residency > data->expected_us)
+-			break;
+ 		if (s->target_residency > data->predicted_us)
+ 			break;
+ 		if (s->exit_latency > latency_req)
+ 			break;
++		if (s->exit_latency * multiplier > data->predicted_us)
++			break;
++		data->exit_us = s->exit_latency;
++		data->last_state_idx = i;
+ 	}
+ 
+-	data->last_state_idx = i - 1;
+-	return i - 1;
++	return data->last_state_idx;
+ }
+ 
+ /**
+@@ -85,35 +244,49 @@ static void menu_reflect(struct cpuidle_device *dev)
+ 	unsigned int last_idle_us = cpuidle_get_last_residency(dev);
+ 	struct cpuidle_state *target = &dev->states[last_idx];
+ 	unsigned int measured_us;
++	u64 new_factor;
+ 
+ 	/*
+ 	 * Ugh, this idle state doesn't support residency measurements, so we
+ 	 * are basically lost in the dark.  As a compromise, assume we slept
+-	 * for one full standard timer tick.  However, be aware that this
+-	 * could potentially result in a suboptimal state transition.
++	 * for the whole expected time.
+ 	 */
+ 	if (unlikely(!(target->flags & CPUIDLE_FLAG_TIME_VALID)))
+-		last_idle_us = USEC_PER_SEC / HZ;
++		last_idle_us = data->expected_us;
++
++
++	measured_us = last_idle_us;
+ 
+ 	/*
+-	 * measured_us and elapsed_us are the cumulative idle time, since the
+-	 * last time we were woken out of idle by an interrupt.
++	 * We correct for the exit latency; we are assuming here that the
++	 * exit latency happens after the event that we're interested in.
+ 	 */
+-	if (data->elapsed_us <= data->elapsed_us + last_idle_us)
+-		measured_us = data->elapsed_us + last_idle_us;
++	if (measured_us > data->exit_us)
++		measured_us -= data->exit_us;
++
++
++	/* update our correction ratio */
++
++	new_factor = data->correction_factor[data->bucket]
++			* (DECAY - 1) / DECAY;
++
++	if (data->expected_us > 0 && data->measured_us < MAX_INTERESTING)
++		new_factor += RESOLUTION * measured_us / data->expected_us;
+ 	else
+-		measured_us = -1;
++		/*
++		 * we were idle so long that we count it as a perfect
++		 * prediction
++		 */
++		new_factor += RESOLUTION;
+ 
+-	/* Predict time until next break event */
+-	data->current_predicted_us = max(measured_us, data->last_measured_us);
++	/*
++	 * We don't want 0 as factor; we always want at least
++	 * a tiny bit of estimated time.
++	 */
++	if (new_factor == 0)
++		new_factor = 1;
+ 
+-	if (last_idle_us + BREAK_FUZZ <
+-	    data->expected_us - target->exit_latency) {
+-		data->last_measured_us = measured_us;
+-		data->elapsed_us = 0;
+-	} else {
+-		data->elapsed_us = measured_us;
+-	}
++	data->correction_factor[data->bucket] = new_factor;
+ }
+ 
+ /**
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index cdc1298..d559406 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -140,6 +140,10 @@ extern int nr_processes(void);
+ extern unsigned long nr_running(void);
+ extern unsigned long nr_uninterruptible(void);
+ extern unsigned long nr_iowait(void);
++extern unsigned long nr_iowait_cpu(void);
++extern unsigned long this_cpu_load(void);
++
++
+ extern void calc_global_load(void);
+ extern u64 cpu_nr_migrations(int cpu);
+ 
+diff --git a/kernel/sched.c b/kernel/sched.c
+index 4dbe8e7..541b370 100644
+--- a/kernel/sched.c
++++ b/kernel/sched.c
+@@ -2910,6 +2910,19 @@ unsigned long nr_iowait(void)
+ 	return sum;
+ }
+ 
++unsigned long nr_iowait_cpu(void)
++{
++	struct rq *this = this_rq();
++	return atomic_read(&this->nr_iowait);
++}
++
++unsigned long this_cpu_load(void)
++{
++	struct rq *this = this_rq();
++	return this->cpu_load[0];
++}
++
++
+ /* Variables and functions for calc_load */
+ static atomic_long_t calc_load_tasks;
+ static unsigned long calc_load_update;
+-- 
+1.6.0.6
+