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authorDeepthi Dharwar <deepthi@linux.vnet.ibm.com>2011-10-28 16:20:42 +0530
committerLen Brown <len.brown@intel.com>2011-11-06 21:13:58 -0500
commit46bcfad7a819bd17ac4e831b04405152d59784ab (patch)
tree20041e788154d103edff2699f88d4a30320e3ee2 /drivers/cpuidle/governors
parent4202735e8ab6ecfb0381631a0d0b58fefe0bd4e2 (diff)
cpuidle: Single/Global registration of idle states
This patch makes the cpuidle_states structure global (single copy) instead of per-cpu. The statistics needed on per-cpu basis by the governor are kept per-cpu. This simplifies the cpuidle subsystem as state registration is done by single cpu only. Having single copy of cpuidle_states saves memory. Rare case of asymmetric C-states can be handled within the cpuidle driver and architectures such as POWER do not have asymmetric C-states. Having single/global registration of all the idle states, dynamic C-state transitions on x86 are handled by the boot cpu. Here, the boot cpu would disable all the devices, re-populate the states and later enable all the devices, irrespective of the cpu that would receive the notification first. Reference: https://lkml.org/lkml/2011/4/25/83 Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> Signed-off-by: Trinabh Gupta <g.trinabh@gmail.com> Tested-by: Jean Pihet <j-pihet@ti.com> Reviewed-by: Kevin Hilman <khilman@ti.com> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/cpuidle/governors')
-rw-r--r--drivers/cpuidle/governors/ladder.c28
-rw-r--r--drivers/cpuidle/governors/menu.c20
2 files changed, 29 insertions, 19 deletions
diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c
index 6a686a76711..ef6b9e4727a 100644
--- a/drivers/cpuidle/governors/ladder.c
+++ b/drivers/cpuidle/governors/ladder.c
@@ -60,9 +60,11 @@ static inline void ladder_do_selection(struct ladder_device *ldev,
/**
* ladder_select_state - selects the next state to enter
+ * @drv: cpuidle driver
* @dev: the CPU
*/
-static int ladder_select_state(struct cpuidle_device *dev)
+static int ladder_select_state(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
{
struct ladder_device *ldev = &__get_cpu_var(ladder_devices);
struct ladder_device_state *last_state;
@@ -77,15 +79,17 @@ static int ladder_select_state(struct cpuidle_device *dev)
last_state = &ldev->states[last_idx];
- if (dev->states[last_idx].flags & CPUIDLE_FLAG_TIME_VALID)
- last_residency = cpuidle_get_last_residency(dev) - dev->states[last_idx].exit_latency;
+ if (drv->states[last_idx].flags & CPUIDLE_FLAG_TIME_VALID) {
+ last_residency = cpuidle_get_last_residency(dev) - \
+ drv->states[last_idx].exit_latency;
+ }
else
last_residency = last_state->threshold.promotion_time + 1;
/* consider promotion */
- if (last_idx < dev->state_count - 1 &&
+ if (last_idx < drv->state_count - 1 &&
last_residency > last_state->threshold.promotion_time &&
- dev->states[last_idx + 1].exit_latency <= latency_req) {
+ drv->states[last_idx + 1].exit_latency <= latency_req) {
last_state->stats.promotion_count++;
last_state->stats.demotion_count = 0;
if (last_state->stats.promotion_count >= last_state->threshold.promotion_count) {
@@ -96,11 +100,11 @@ static int ladder_select_state(struct cpuidle_device *dev)
/* consider demotion */
if (last_idx > CPUIDLE_DRIVER_STATE_START &&
- dev->states[last_idx].exit_latency > latency_req) {
+ drv->states[last_idx].exit_latency > latency_req) {
int i;
for (i = last_idx - 1; i > CPUIDLE_DRIVER_STATE_START; i--) {
- if (dev->states[i].exit_latency <= latency_req)
+ if (drv->states[i].exit_latency <= latency_req)
break;
}
ladder_do_selection(ldev, last_idx, i);
@@ -123,9 +127,11 @@ static int ladder_select_state(struct cpuidle_device *dev)
/**
* ladder_enable_device - setup for the governor
+ * @drv: cpuidle driver
* @dev: the CPU
*/
-static int ladder_enable_device(struct cpuidle_device *dev)
+static int ladder_enable_device(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
{
int i;
struct ladder_device *ldev = &per_cpu(ladder_devices, dev->cpu);
@@ -134,8 +140,8 @@ static int ladder_enable_device(struct cpuidle_device *dev)
ldev->last_state_idx = CPUIDLE_DRIVER_STATE_START;
- for (i = 0; i < dev->state_count; i++) {
- state = &dev->states[i];
+ for (i = 0; i < drv->state_count; i++) {
+ state = &drv->states[i];
lstate = &ldev->states[i];
lstate->stats.promotion_count = 0;
@@ -144,7 +150,7 @@ static int ladder_enable_device(struct cpuidle_device *dev)
lstate->threshold.promotion_count = PROMOTION_COUNT;
lstate->threshold.demotion_count = DEMOTION_COUNT;
- if (i < dev->state_count - 1)
+ if (i < drv->state_count - 1)
lstate->threshold.promotion_time = state->exit_latency;
if (i > 0)
lstate->threshold.demotion_time = state->exit_latency;
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index af724e823c8..bcbe8814213 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -182,7 +182,7 @@ static inline int performance_multiplier(void)
static DEFINE_PER_CPU(struct menu_device, menu_devices);
-static void menu_update(struct cpuidle_device *dev);
+static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev);
/* This implements DIV_ROUND_CLOSEST but avoids 64 bit division */
static u64 div_round64(u64 dividend, u32 divisor)
@@ -228,9 +228,10 @@ static void detect_repeating_patterns(struct menu_device *data)
/**
* menu_select - selects the next idle state to enter
+ * @drv: cpuidle driver containing state data
* @dev: the CPU
*/
-static int menu_select(struct cpuidle_device *dev)
+static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
@@ -240,7 +241,7 @@ static int menu_select(struct cpuidle_device *dev)
struct timespec t;
if (data->needs_update) {
- menu_update(dev);
+ menu_update(drv, dev);
data->needs_update = 0;
}
@@ -285,8 +286,8 @@ static int menu_select(struct cpuidle_device *dev)
* Find the idle state with the lowest power while satisfying
* our constraints.
*/
- for (i = CPUIDLE_DRIVER_STATE_START; i < dev->state_count; i++) {
- struct cpuidle_state *s = &dev->states[i];
+ for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+ struct cpuidle_state *s = &drv->states[i];
if (s->target_residency > data->predicted_us)
continue;
@@ -323,14 +324,15 @@ static void menu_reflect(struct cpuidle_device *dev, int index)
/**
* menu_update - attempts to guess what happened after entry
+ * @drv: cpuidle driver containing state data
* @dev: the CPU
*/
-static void menu_update(struct cpuidle_device *dev)
+static void menu_update(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
struct menu_device *data = &__get_cpu_var(menu_devices);
int last_idx = data->last_state_idx;
unsigned int last_idle_us = cpuidle_get_last_residency(dev);
- struct cpuidle_state *target = &dev->states[last_idx];
+ struct cpuidle_state *target = &drv->states[last_idx];
unsigned int measured_us;
u64 new_factor;
@@ -384,9 +386,11 @@ static void menu_update(struct cpuidle_device *dev)
/**
* menu_enable_device - scans a CPU's states and does setup
+ * @drv: cpuidle driver
* @dev: the CPU
*/
-static int menu_enable_device(struct cpuidle_device *dev)
+static int menu_enable_device(struct cpuidle_driver *drv,
+ struct cpuidle_device *dev)
{
struct menu_device *data = &per_cpu(menu_devices, dev->cpu);