* [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE
@ 2007-09-13 20:40 Venki Pallipadi
2007-09-22 3:00 ` Len Brown
2007-09-25 22:13 ` Len Brown
0 siblings, 2 replies; 4+ messages in thread
From: Venki Pallipadi @ 2007-09-13 20:40 UTC (permalink / raw)
To: Len Brown; +Cc: linux-acpi, abelay
Retain the old policy in processor_idle, so that when CPU_IDLE is not
configured, old C-state policy will still be used. This provides a
clean gradual migration path from old acpi policy to new cpuidle
based policy.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Index: linux-2.6.23-rc6/drivers/acpi/processor_idle.c
===================================================================
--- linux-2.6.23-rc6.orig/drivers/acpi/processor_idle.c
+++ linux-2.6.23-rc6/drivers/acpi/processor_idle.c
@@ -65,14 +65,20 @@ ACPI_MODULE_NAME("processor_idle");
#define ACPI_PROCESSOR_FILE_POWER "power"
#define PM_TIMER_TICKS_TO_US(p) (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
#define PM_TIMER_TICK_NS (1000000000ULL/PM_TIMER_FREQUENCY)
-#define C2_OVERHEAD 1 /* 1us */
-#define C3_OVERHEAD 1 /* 1us */
static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
module_param(max_cstate, uint, 0000);
static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);
+#ifndef CONFIG_CPU_IDLE
+
+#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr);
+
+#endif
+
/*
* IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
* For now disable this. Probably a bug somewhere else.
@@ -447,7 +453,12 @@ static void acpi_processor_power_verify_
* Normalize the C2 latency to expidite policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -527,7 +538,12 @@ static void acpi_processor_power_verify_
* use this in our C3 policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -592,6 +608,20 @@ static int acpi_processor_get_power_info
pr->power.count = acpi_processor_power_verify(pr);
+#ifndef CONFIG_CPU_IDLE
+ /*
+ * Set Default Policy
+ * ------------------
+ * Now that we know which states are supported, set the default
+ * policy. Note that this policy can be changed dynamically
+ * (e.g. encourage deeper sleeps to conserve battery life when
+ * not on AC).
+ */
+ result = acpi_processor_set_power_policy(pr);
+ if (result)
+ return result;
+#endif
+
/*
* if one state of type C2 or C3 is available, mark this
* CPU as being "idle manageable"
@@ -708,6 +738,11 @@ static inline u32 ticks_elapsed(u32 t1,
return ((0xFFFFFFFF - t1) + t2);
}
+#ifdef CONFIG_CPU_IDLE
+
+#define C2_OVERHEAD 1 /* 1us */
+#define C3_OVERHEAD 1 /* 1us */
+
/**
* acpi_idle_bm_check - checks if bus master activity was detected
*/
@@ -1088,6 +1123,552 @@ int acpi_processor_cst_has_changed(struc
return ret;
}
+#else
+
+/*
+ * This code provides the older acpi behaviour when cpuidle is not configured.
+ * This will go away once CPU_IDLE has been fully integrated into the mainline
+ * kernel. -- Venki --
+ */
+#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+static void (*pm_idle_save) (void) __read_mostly;
+
+/*
+ * bm_history -- bit-mask with a bit per jiffy of bus-master activity
+ * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
+ * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
+ * 100 HZ: 0x0000000F: 4 jiffies = 40ms
+ * reduce history for more aggressive entry into C3
+ */
+static unsigned int bm_history __read_mostly =
+ (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
+module_param(bm_history, uint, 0644);
+
+static void
+acpi_processor_power_activate(struct acpi_processor *pr,
+ struct acpi_processor_cx *new)
+{
+ struct acpi_processor_cx *old;
+
+ if (!pr || !new)
+ return;
+
+ old = pr->power.state;
+
+ if (old)
+ old->promotion.count = 0;
+ new->demotion.count = 0;
+
+ /* Cleanup from old state. */
+ if (old) {
+ switch (old->type) {
+ case ACPI_STATE_C3:
+ /* Disable bus master reload */
+ if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
+ break;
+ }
+ }
+
+ /* Prepare to use new state. */
+ switch (new->type) {
+ case ACPI_STATE_C3:
+ /* Enable bus master reload */
+ if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+ break;
+ }
+
+ pr->power.state = new;
+
+ return;
+}
+
+static void acpi_safe_halt(void)
+{
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (!need_resched())
+ safe_halt();
+ current_thread_info()->status |= TS_POLLING;
+}
+
+static atomic_t c3_cpu_count;
+
+/* Common C-state entry for C2, C3, .. */
+static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
+{
+ if (cstate->space_id == ACPI_CSTATE_FFH) {
+ /* Call into architectural FFH based C-state */
+ acpi_processor_ffh_cstate_enter(cstate);
+ } else {
+ int unused;
+ /* IO port based C-state */
+ inb(cstate->address);
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ }
+}
+
+static void acpi_processor_idle(void)
+{
+ struct acpi_processor *pr = NULL;
+ struct acpi_processor_cx *cx = NULL;
+ struct acpi_processor_cx *next_state = NULL;
+ int sleep_ticks = 0;
+ u32 t1, t2 = 0;
+
+ /*
+ * Interrupts must be disabled during bus mastering calculations and
+ * for C2/C3 transitions.
+ */
+ local_irq_disable();
+
+ pr = processors[smp_processor_id()];
+ if (!pr) {
+ local_irq_enable();
+ return;
+ }
+
+ /*
+ * Check whether we truly need to go idle, or should
+ * reschedule:
+ */
+ if (unlikely(need_resched())) {
+ local_irq_enable();
+ return;
+ }
+
+ cx = pr->power.state;
+ if (!cx) {
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+ return;
+ }
+
+ /*
+ * Check BM Activity
+ * -----------------
+ * Check for bus mastering activity (if required), record, and check
+ * for demotion.
+ */
+ if (pr->flags.bm_check) {
+ u32 bm_status = 0;
+ unsigned long diff = jiffies - pr->power.bm_check_timestamp;
+
+ if (diff > 31)
+ diff = 31;
+
+ pr->power.bm_activity <<= diff;
+
+ acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+ if (bm_status) {
+ pr->power.bm_activity |= 0x1;
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+ }
+ /*
+ * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+ * the true state of bus mastering activity; forcing us to
+ * manually check the BMIDEA bit of each IDE channel.
+ */
+ else if (errata.piix4.bmisx) {
+ if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+ || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+ pr->power.bm_activity |= 0x1;
+ }
+
+ pr->power.bm_check_timestamp = jiffies;
+
+ /*
+ * If bus mastering is or was active this jiffy, demote
+ * to avoid a faulty transition. Note that the processor
+ * won't enter a low-power state during this call (to this
+ * function) but should upon the next.
+ *
+ * TBD: A better policy might be to fallback to the demotion
+ * state (use it for this quantum only) istead of
+ * demoting -- and rely on duration as our sole demotion
+ * qualification. This may, however, introduce DMA
+ * issues (e.g. floppy DMA transfer overrun/underrun).
+ */
+ if ((pr->power.bm_activity & 0x1) &&
+ cx->demotion.threshold.bm) {
+ local_irq_enable();
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system. We do it here instead of doing it at _CST/P_LVL
+ * detection phase, to work cleanly with logical CPU hotplug.
+ */
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ cx = &pr->power.states[ACPI_STATE_C1];
+#endif
+
+ /*
+ * Sleep:
+ * ------
+ * Invoke the current Cx state to put the processor to sleep.
+ */
+ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (need_resched()) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return;
+ }
+ }
+
+ switch (cx->type) {
+
+ case ACPI_STATE_C1:
+ /*
+ * Invoke C1.
+ * Use the appropriate idle routine, the one that would
+ * be used without acpi C-states.
+ */
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+
+ /*
+ * TBD: Can't get time duration while in C1, as resumes
+ * go to an ISR rather than here. Need to instrument
+ * base interrupt handler.
+ *
+ * Note: the TSC better not stop in C1, sched_clock() will
+ * skew otherwise.
+ */
+ sleep_ticks = 0xFFFFFFFF;
+ break;
+
+ case ACPI_STATE_C2:
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ /* Invoke C2 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable("possible TSC halt in C2");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ case ACPI_STATE_C3:
+ /*
+ * disable bus master
+ * bm_check implies we need ARB_DIS
+ * !bm_check implies we need cache flush
+ * bm_control implies whether we can do ARB_DIS
+ *
+ * That leaves a case where bm_check is set and bm_control is
+ * not set. In that case we cannot do much, we enter C3
+ * without doing anything.
+ */
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ if (atomic_inc_return(&c3_cpu_count) ==
+ num_online_cpus()) {
+ /*
+ * All CPUs are trying to go to C3
+ * Disable bus master arbitration
+ */
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
+ }
+ } else if (!pr->flags.bm_check) {
+ /* SMP with no shared cache... Invalidate cache */
+ ACPI_FLUSH_CPU_CACHE();
+ }
+
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Invoke C3 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ /* Enable bus master arbitration */
+ atomic_dec(&c3_cpu_count);
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
+ }
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable("TSC halts in C3");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ default:
+ local_irq_enable();
+ return;
+ }
+ cx->usage++;
+ if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+ cx->time += sleep_ticks;
+
+ next_state = pr->power.state;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /* Don't do promotion/demotion */
+ if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
+ next_state = cx;
+ goto end;
+ }
+#endif
+
+ /*
+ * Promotion?
+ * ----------
+ * Track the number of longs (time asleep is greater than threshold)
+ * and promote when the count threshold is reached. Note that bus
+ * mastering activity may prevent promotions.
+ * Do not promote above max_cstate.
+ */
+ if (cx->promotion.state &&
+ ((cx->promotion.state - pr->power.states) <= max_cstate)) {
+ if (sleep_ticks > cx->promotion.threshold.ticks &&
+ cx->promotion.state->latency <= system_latency_constraint()) {
+ cx->promotion.count++;
+ cx->demotion.count = 0;
+ if (cx->promotion.count >=
+ cx->promotion.threshold.count) {
+ if (pr->flags.bm_check) {
+ if (!
+ (pr->power.bm_activity & cx->
+ promotion.threshold.bm)) {
+ next_state =
+ cx->promotion.state;
+ goto end;
+ }
+ } else {
+ next_state = cx->promotion.state;
+ goto end;
+ }
+ }
+ }
+ }
+
+ /*
+ * Demotion?
+ * ---------
+ * Track the number of shorts (time asleep is less than time threshold)
+ * and demote when the usage threshold is reached.
+ */
+ if (cx->demotion.state) {
+ if (sleep_ticks < cx->demotion.threshold.ticks) {
+ cx->demotion.count++;
+ cx->promotion.count = 0;
+ if (cx->demotion.count >= cx->demotion.threshold.count) {
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+ }
+
+ end:
+ /*
+ * Demote if current state exceeds max_cstate
+ * or if the latency of the current state is unacceptable
+ */
+ if ((pr->power.state - pr->power.states) > max_cstate ||
+ pr->power.state->latency > system_latency_constraint()) {
+ if (cx->demotion.state)
+ next_state = cx->demotion.state;
+ }
+
+ /*
+ * New Cx State?
+ * -------------
+ * If we're going to start using a new Cx state we must clean up
+ * from the previous and prepare to use the new.
+ */
+ if (next_state != pr->power.state)
+ acpi_processor_power_activate(pr, next_state);
+}
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr)
+{
+ unsigned int i;
+ unsigned int state_is_set = 0;
+ struct acpi_processor_cx *lower = NULL;
+ struct acpi_processor_cx *higher = NULL;
+ struct acpi_processor_cx *cx;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ /*
+ * This function sets the default Cx state policy (OS idle handler).
+ * Our scheme is to promote quickly to C2 but more conservatively
+ * to C3. We're favoring C2 for its characteristics of low latency
+ * (quick response), good power savings, and ability to allow bus
+ * mastering activity. Note that the Cx state policy is completely
+ * customizable and can be altered dynamically.
+ */
+
+ /* startup state */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (!state_is_set)
+ pr->power.state = cx;
+ state_is_set++;
+ break;
+ }
+
+ if (!state_is_set)
+ return -ENODEV;
+
+ /* demotion */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (lower) {
+ cx->demotion.state = lower;
+ cx->demotion.threshold.ticks = cx->latency_ticks;
+ cx->demotion.threshold.count = 1;
+ if (cx->type == ACPI_STATE_C3)
+ cx->demotion.threshold.bm = bm_history;
+ }
+
+ lower = cx;
+ }
+
+ /* promotion */
+ for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (higher) {
+ cx->promotion.state = higher;
+ cx->promotion.threshold.ticks = cx->latency_ticks;
+ if (cx->type >= ACPI_STATE_C2)
+ cx->promotion.threshold.count = 4;
+ else
+ cx->promotion.threshold.count = 10;
+ if (higher->type == ACPI_STATE_C3)
+ cx->promotion.threshold.bm = bm_history;
+ }
+
+ higher = cx;
+ }
+
+ return 0;
+}
+
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+ int result = 0;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst) {
+ return -ENODEV;
+ }
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /* Fall back to the default idle loop */
+ pm_idle = pm_idle_save;
+ synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
+
+ pr->flags.power = 0;
+ result = acpi_processor_get_power_info(pr);
+ if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
+ pm_idle = acpi_processor_idle;
+
+ return result;
+}
+
+#ifdef CONFIG_SMP
+static void smp_callback(void *v)
+{
+ /* we already woke the CPU up, nothing more to do */
+}
+
+/*
+ * This function gets called when a part of the kernel has a new latency
+ * requirement. This means we need to get all processors out of their C-state,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int acpi_processor_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_processor_latency_notifier = {
+ .notifier_call = acpi_processor_latency_notify,
+};
+
+#endif
+
+#endif
+
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
@@ -1104,6 +1685,9 @@ int __cpuinit acpi_processor_power_init(
"ACPI: processor limited to max C-state %d\n",
max_cstate);
first_run++;
+#if !defined (CONFIG_CPU_IDLE) && defined (CONFIG_SMP)
+ register_latency_notifier(&acpi_processor_latency_notifier);
+#endif
}
if (!pr)
@@ -1127,10 +1711,12 @@ int __cpuinit acpi_processor_power_init(
* platforms that only support C1.
*/
if ((pr->flags.power) && (!boot_option_idle_override)) {
+#ifdef CONFIG_CPU_IDLE
acpi_processor_setup_cpuidle(pr);
pr->power.dev.cpu = pr->id;
if (cpuidle_register_device(&pr->power.dev))
return -EIO;
+#endif
printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
for (i = 1; i <= pr->power.count; i++)
@@ -1138,6 +1724,13 @@ int __cpuinit acpi_processor_power_init(
printk(" C%d[C%d]", i,
pr->power.states[i].type);
printk(")\n");
+
+#ifndef CONFIG_CPU_IDLE
+ if (pr->id == 0) {
+ pm_idle_save = pm_idle;
+ pm_idle = acpi_processor_idle;
+ }
+#endif
}
/* 'power' [R] */
@@ -1157,12 +1750,33 @@ int __cpuinit acpi_processor_power_init(
int acpi_processor_power_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
+#ifdef CONFIG_CPU_IDLE
if ((pr->flags.power) && (!boot_option_idle_override))
cpuidle_unregister_device(&pr->power.dev);
+#endif
pr->flags.power_setup_done = 0;
if (acpi_device_dir(device))
remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
acpi_device_dir(device));
+
+#ifndef CONFIG_CPU_IDLE
+
+ /* Unregister the idle handler when processor #0 is removed. */
+ if (pr->id == 0) {
+ pm_idle = pm_idle_save;
+
+ /*
+ * We are about to unload the current idle thread pm callback
+ * (pm_idle), Wait for all processors to update cached/local
+ * copies of pm_idle before proceeding.
+ */
+ cpu_idle_wait();
+#ifdef CONFIG_SMP
+ unregister_latency_notifier(&acpi_processor_latency_notifier);
+#endif
+ }
+#endif
+
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE
2007-09-13 20:40 [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE Venki Pallipadi
@ 2007-09-22 3:00 ` Len Brown
2007-09-25 22:13 ` Len Brown
1 sibling, 0 replies; 4+ messages in thread
From: Len Brown @ 2007-09-22 3:00 UTC (permalink / raw)
To: Venki Pallipadi; +Cc: linux-acpi, abelay
I couldn't get this patch to apply.
the current cpuidle branch is rooted at 2.6.22.
I'd like to see a patch on top of that branch
that restores as much of processor_idle.c as possible
to the state in 2.6.22.
ie. a diff of 2.6.22 and cpuidle processor_idle.c
should be as small as possible -- and it is okay
to use a bunch of CONFIG_CPU_IDLE ifdefs to keep things simple.
I can take care of merging that with the other changes
to processor_idle.c that have come along in 2.6.23.
thanks,
-Len
On Thursday 13 September 2007 16:40, Venki Pallipadi wrote:
>
> Retain the old policy in processor_idle, so that when CPU_IDLE is not
> configured, old C-state policy will still be used. This provides a
> clean gradual migration path from old acpi policy to new cpuidle
> based policy.
>
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
>
> Index: linux-2.6.23-rc6/drivers/acpi/processor_idle.c
> ===================================================================
> --- linux-2.6.23-rc6.orig/drivers/acpi/processor_idle.c
> +++ linux-2.6.23-rc6/drivers/acpi/processor_idle.c
> @@ -65,14 +65,20 @@ ACPI_MODULE_NAME("processor_idle");
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE
2007-09-13 20:40 [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE Venki Pallipadi
2007-09-22 3:00 ` Len Brown
@ 2007-09-25 22:13 ` Len Brown
2007-09-26 6:16 ` [PATCH] cpuidle: reduce diff size Len Brown
1 sibling, 1 reply; 4+ messages in thread
From: Len Brown @ 2007-09-25 22:13 UTC (permalink / raw)
To: Venki Pallipadi; +Cc: linux-acpi, abelay
From: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Retain the old policy in processor_idle, so that when CPU_IDLE is not
configured, old C-state policy will still be used. This provides a
clean gradual migration path from old acpi policy to new cpuidle
based policy.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
Okay, here's a refreshed version that applies cleanly on top of the
existing 2.6.22 cpuidle series.
processor_idle.c | 618 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 616 insertions(+), 2 deletions(-)
Index: acpi/drivers/acpi/processor_idle.c
===================================================================
--- acpi.orig/drivers/acpi/processor_idle.c
+++ acpi/drivers/acpi/processor_idle.c
@@ -64,14 +64,20 @@
ACPI_MODULE_NAME("processor_idle");
#define ACPI_PROCESSOR_FILE_POWER "power"
#define PM_TIMER_TICKS_TO_US(p) (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
-#define C2_OVERHEAD 1 /* 1us */
-#define C3_OVERHEAD 1 /* 1us */
static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
module_param(max_cstate, uint, 0000);
static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);
+#ifndef CONFIG_CPU_IDLE
+
+#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr);
+
+#endif
+
/*
* IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
* For now disable this. Probably a bug somewhere else.
@@ -446,7 +452,12 @@ static void acpi_processor_power_verify_
* Normalize the C2 latency to expidite policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -520,7 +531,12 @@ static void acpi_processor_power_verify_
* use this in our C3 policy
*/
cx->valid = 1;
+
+#ifdef CONFIG_CPU_IDLE
cx->latency_ticks = cx->latency;
+#else
+ cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#endif
return;
}
@@ -585,6 +601,20 @@ static int acpi_processor_get_power_info
pr->power.count = acpi_processor_power_verify(pr);
+#ifndef CONFIG_CPU_IDLE
+ /*
+ * Set Default Policy
+ * ------------------
+ * Now that we know which states are supported, set the default
+ * policy. Note that this policy can be changed dynamically
+ * (e.g. encourage deeper sleeps to conserve battery life when
+ * not on AC).
+ */
+ result = acpi_processor_set_power_policy(pr);
+ if (result)
+ return result;
+#endif
+
/*
* if one state of type C2 or C3 is available, mark this
* CPU as being "idle manageable"
@@ -701,6 +731,11 @@ static inline u32 ticks_elapsed(u32 t1,
return ((0xFFFFFFFF - t1) + t2);
}
+#ifdef CONFIG_CPU_IDLE
+
+#define C2_OVERHEAD 1 /* 1us */
+#define C3_OVERHEAD 1 /* 1us */
+
/**
* acpi_idle_bm_check - checks if bus master activity was detected
*/
@@ -1049,6 +1084,552 @@ int acpi_processor_cst_has_changed(struc
return ret;
}
+#else
+
+/*
+ * This code provides the older acpi behaviour when cpuidle is not configured.
+ * This will go away once CPU_IDLE has been fully integrated into the mainline
+ * kernel. -- Venki --
+ */
+#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+static void (*pm_idle_save) (void) __read_mostly;
+
+/*
+ * bm_history -- bit-mask with a bit per jiffy of bus-master activity
+ * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
+ * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
+ * 100 HZ: 0x0000000F: 4 jiffies = 40ms
+ * reduce history for more aggressive entry into C3
+ */
+static unsigned int bm_history __read_mostly =
+ (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
+module_param(bm_history, uint, 0644);
+
+static void
+acpi_processor_power_activate(struct acpi_processor *pr,
+ struct acpi_processor_cx *new)
+{
+ struct acpi_processor_cx *old;
+
+ if (!pr || !new)
+ return;
+
+ old = pr->power.state;
+
+ if (old)
+ old->promotion.count = 0;
+ new->demotion.count = 0;
+
+ /* Cleanup from old state. */
+ if (old) {
+ switch (old->type) {
+ case ACPI_STATE_C3:
+ /* Disable bus master reload */
+ if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
+ break;
+ }
+ }
+
+ /* Prepare to use new state. */
+ switch (new->type) {
+ case ACPI_STATE_C3:
+ /* Enable bus master reload */
+ if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+ break;
+ }
+
+ pr->power.state = new;
+
+ return;
+}
+
+static void acpi_safe_halt(void)
+{
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (!need_resched())
+ safe_halt();
+ current_thread_info()->status |= TS_POLLING;
+}
+
+static atomic_t c3_cpu_count;
+
+/* Common C-state entry for C2, C3, .. */
+static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
+{
+ if (cstate->space_id == ACPI_CSTATE_FFH) {
+ /* Call into architectural FFH based C-state */
+ acpi_processor_ffh_cstate_enter(cstate);
+ } else {
+ int unused;
+ /* IO port based C-state */
+ inb(cstate->address);
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ }
+}
+
+static void acpi_processor_idle(void)
+{
+ struct acpi_processor *pr = NULL;
+ struct acpi_processor_cx *cx = NULL;
+ struct acpi_processor_cx *next_state = NULL;
+ int sleep_ticks = 0;
+ u32 t1, t2 = 0;
+
+ /*
+ * Interrupts must be disabled during bus mastering calculations and
+ * for C2/C3 transitions.
+ */
+ local_irq_disable();
+
+ pr = processors[smp_processor_id()];
+ if (!pr) {
+ local_irq_enable();
+ return;
+ }
+
+ /*
+ * Check whether we truly need to go idle, or should
+ * reschedule:
+ */
+ if (unlikely(need_resched())) {
+ local_irq_enable();
+ return;
+ }
+
+ cx = pr->power.state;
+ if (!cx) {
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+ return;
+ }
+
+ /*
+ * Check BM Activity
+ * -----------------
+ * Check for bus mastering activity (if required), record, and check
+ * for demotion.
+ */
+ if (pr->flags.bm_check) {
+ u32 bm_status = 0;
+ unsigned long diff = jiffies - pr->power.bm_check_timestamp;
+
+ if (diff > 31)
+ diff = 31;
+
+ pr->power.bm_activity <<= diff;
+
+ acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+ if (bm_status) {
+ pr->power.bm_activity |= 0x1;
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+ }
+ /*
+ * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+ * the true state of bus mastering activity; forcing us to
+ * manually check the BMIDEA bit of each IDE channel.
+ */
+ else if (errata.piix4.bmisx) {
+ if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+ || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+ pr->power.bm_activity |= 0x1;
+ }
+
+ pr->power.bm_check_timestamp = jiffies;
+
+ /*
+ * If bus mastering is or was active this jiffy, demote
+ * to avoid a faulty transition. Note that the processor
+ * won't enter a low-power state during this call (to this
+ * function) but should upon the next.
+ *
+ * TBD: A better policy might be to fallback to the demotion
+ * state (use it for this quantum only) istead of
+ * demoting -- and rely on duration as our sole demotion
+ * qualification. This may, however, introduce DMA
+ * issues (e.g. floppy DMA transfer overrun/underrun).
+ */
+ if ((pr->power.bm_activity & 0x1) &&
+ cx->demotion.threshold.bm) {
+ local_irq_enable();
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system. We do it here instead of doing it at _CST/P_LVL
+ * detection phase, to work cleanly with logical CPU hotplug.
+ */
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ cx = &pr->power.states[ACPI_STATE_C1];
+#endif
+
+ /*
+ * Sleep:
+ * ------
+ * Invoke the current Cx state to put the processor to sleep.
+ */
+ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (need_resched()) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return;
+ }
+ }
+
+ switch (cx->type) {
+
+ case ACPI_STATE_C1:
+ /*
+ * Invoke C1.
+ * Use the appropriate idle routine, the one that would
+ * be used without acpi C-states.
+ */
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+
+ /*
+ * TBD: Can't get time duration while in C1, as resumes
+ * go to an ISR rather than here. Need to instrument
+ * base interrupt handler.
+ *
+ * Note: the TSC better not stop in C1, sched_clock() will
+ * skew otherwise.
+ */
+ sleep_ticks = 0xFFFFFFFF;
+ break;
+
+ case ACPI_STATE_C2:
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ /* Invoke C2 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable("possible TSC halt in C2");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ case ACPI_STATE_C3:
+ /*
+ * disable bus master
+ * bm_check implies we need ARB_DIS
+ * !bm_check implies we need cache flush
+ * bm_control implies whether we can do ARB_DIS
+ *
+ * That leaves a case where bm_check is set and bm_control is
+ * not set. In that case we cannot do much, we enter C3
+ * without doing anything.
+ */
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ if (atomic_inc_return(&c3_cpu_count) ==
+ num_online_cpus()) {
+ /*
+ * All CPUs are trying to go to C3
+ * Disable bus master arbitration
+ */
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
+ }
+ } else if (!pr->flags.bm_check) {
+ /* SMP with no shared cache... Invalidate cache */
+ ACPI_FLUSH_CPU_CACHE();
+ }
+
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Invoke C3 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ /* Tell the scheduler that we are going deep-idle: */
+ sched_clock_idle_sleep_event();
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ /* Enable bus master arbitration */
+ atomic_dec(&c3_cpu_count);
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
+ }
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable("TSC halts in C3");
+#endif
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks = ticks_elapsed(t1, t2);
+ /* Tell the scheduler how much we idled: */
+ sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
+ /* Re-enable interrupts */
+ local_irq_enable();
+ /* Do not account our idle-switching overhead: */
+ sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
+
+ current_thread_info()->status |= TS_POLLING;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ default:
+ local_irq_enable();
+ return;
+ }
+ cx->usage++;
+ if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+ cx->time += sleep_ticks;
+
+ next_state = pr->power.state;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /* Don't do promotion/demotion */
+ if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
+ next_state = cx;
+ goto end;
+ }
+#endif
+
+ /*
+ * Promotion?
+ * ----------
+ * Track the number of longs (time asleep is greater than threshold)
+ * and promote when the count threshold is reached. Note that bus
+ * mastering activity may prevent promotions.
+ * Do not promote above max_cstate.
+ */
+ if (cx->promotion.state &&
+ ((cx->promotion.state - pr->power.states) <= max_cstate)) {
+ if (sleep_ticks > cx->promotion.threshold.ticks &&
+ cx->promotion.state->latency <= system_latency_constraint()) {
+ cx->promotion.count++;
+ cx->demotion.count = 0;
+ if (cx->promotion.count >=
+ cx->promotion.threshold.count) {
+ if (pr->flags.bm_check) {
+ if (!
+ (pr->power.bm_activity & cx->
+ promotion.threshold.bm)) {
+ next_state =
+ cx->promotion.state;
+ goto end;
+ }
+ } else {
+ next_state = cx->promotion.state;
+ goto end;
+ }
+ }
+ }
+ }
+
+ /*
+ * Demotion?
+ * ---------
+ * Track the number of shorts (time asleep is less than time threshold)
+ * and demote when the usage threshold is reached.
+ */
+ if (cx->demotion.state) {
+ if (sleep_ticks < cx->demotion.threshold.ticks) {
+ cx->demotion.count++;
+ cx->promotion.count = 0;
+ if (cx->demotion.count >= cx->demotion.threshold.count) {
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+ }
+
+ end:
+ /*
+ * Demote if current state exceeds max_cstate
+ * or if the latency of the current state is unacceptable
+ */
+ if ((pr->power.state - pr->power.states) > max_cstate ||
+ pr->power.state->latency > system_latency_constraint()) {
+ if (cx->demotion.state)
+ next_state = cx->demotion.state;
+ }
+
+ /*
+ * New Cx State?
+ * -------------
+ * If we're going to start using a new Cx state we must clean up
+ * from the previous and prepare to use the new.
+ */
+ if (next_state != pr->power.state)
+ acpi_processor_power_activate(pr, next_state);
+}
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr)
+{
+ unsigned int i;
+ unsigned int state_is_set = 0;
+ struct acpi_processor_cx *lower = NULL;
+ struct acpi_processor_cx *higher = NULL;
+ struct acpi_processor_cx *cx;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ /*
+ * This function sets the default Cx state policy (OS idle handler).
+ * Our scheme is to promote quickly to C2 but more conservatively
+ * to C3. We're favoring C2 for its characteristics of low latency
+ * (quick response), good power savings, and ability to allow bus
+ * mastering activity. Note that the Cx state policy is completely
+ * customizable and can be altered dynamically.
+ */
+
+ /* startup state */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (!state_is_set)
+ pr->power.state = cx;
+ state_is_set++;
+ break;
+ }
+
+ if (!state_is_set)
+ return -ENODEV;
+
+ /* demotion */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (lower) {
+ cx->demotion.state = lower;
+ cx->demotion.threshold.ticks = cx->latency_ticks;
+ cx->demotion.threshold.count = 1;
+ if (cx->type == ACPI_STATE_C3)
+ cx->demotion.threshold.bm = bm_history;
+ }
+
+ lower = cx;
+ }
+
+ /* promotion */
+ for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (higher) {
+ cx->promotion.state = higher;
+ cx->promotion.threshold.ticks = cx->latency_ticks;
+ if (cx->type >= ACPI_STATE_C2)
+ cx->promotion.threshold.count = 4;
+ else
+ cx->promotion.threshold.count = 10;
+ if (higher->type == ACPI_STATE_C3)
+ cx->promotion.threshold.bm = bm_history;
+ }
+
+ higher = cx;
+ }
+
+ return 0;
+}
+
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
+{
+ int result = 0;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst) {
+ return -ENODEV;
+ }
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /* Fall back to the default idle loop */
+ pm_idle = pm_idle_save;
+ synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
+
+ pr->flags.power = 0;
+ result = acpi_processor_get_power_info(pr);
+ if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
+ pm_idle = acpi_processor_idle;
+
+ return result;
+}
+
+#ifdef CONFIG_SMP
+static void smp_callback(void *v)
+{
+ /* we already woke the CPU up, nothing more to do */
+}
+
+/*
+ * This function gets called when a part of the kernel has a new latency
+ * requirement. This means we need to get all processors out of their C-state,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int acpi_processor_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
+
+static struct notifier_block acpi_processor_latency_notifier = {
+ .notifier_call = acpi_processor_latency_notify,
+};
+
+#endif
+
+#endif
+
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
{
@@ -1065,6 +1646,9 @@ int __cpuinit acpi_processor_power_init(
"ACPI: processor limited to max C-state %d\n",
max_cstate);
first_run++;
+#if !defined (CONFIG_CPU_IDLE) && defined (CONFIG_SMP)
+ register_latency_notifier(&acpi_processor_latency_notifier);
+#endif
}
if (!pr)
@@ -1088,10 +1672,12 @@ int __cpuinit acpi_processor_power_init(
* platforms that only support C1.
*/
if ((pr->flags.power) && (!boot_option_idle_override)) {
+#ifdef CONFIG_CPU_IDLE
acpi_processor_setup_cpuidle(pr);
pr->power.dev.cpu = pr->id;
if (cpuidle_register_device(&pr->power.dev))
return -EIO;
+#endif
printk(KERN_INFO PREFIX "CPU%d (power states:", pr->id);
for (i = 1; i <= pr->power.count; i++)
@@ -1099,6 +1685,13 @@ int __cpuinit acpi_processor_power_init(
printk(" C%d[C%d]", i,
pr->power.states[i].type);
printk(")\n");
+
+#ifndef CONFIG_CPU_IDLE
+ if (pr->id == 0) {
+ pm_idle_save = pm_idle;
+ pm_idle = acpi_processor_idle;
+ }
+#endif
}
/* 'power' [R] */
@@ -1118,12 +1711,33 @@ int __cpuinit acpi_processor_power_init(
int acpi_processor_power_exit(struct acpi_processor *pr,
struct acpi_device *device)
{
+#ifdef CONFIG_CPU_IDLE
if ((pr->flags.power) && (!boot_option_idle_override))
cpuidle_unregister_device(&pr->power.dev);
+#endif
pr->flags.power_setup_done = 0;
if (acpi_device_dir(device))
remove_proc_entry(ACPI_PROCESSOR_FILE_POWER,
acpi_device_dir(device));
+
+#ifndef CONFIG_CPU_IDLE
+
+ /* Unregister the idle handler when processor #0 is removed. */
+ if (pr->id == 0) {
+ pm_idle = pm_idle_save;
+
+ /*
+ * We are about to unload the current idle thread pm callback
+ * (pm_idle), Wait for all processors to update cached/local
+ * copies of pm_idle before proceeding.
+ */
+ cpu_idle_wait();
+#ifdef CONFIG_SMP
+ unregister_latency_notifier(&acpi_processor_latency_notifier);
+#endif
+ }
+#endif
+
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] cpuidle: reduce diff size
2007-09-25 22:13 ` Len Brown
@ 2007-09-26 6:16 ` Len Brown
0 siblings, 0 replies; 4+ messages in thread
From: Len Brown @ 2007-09-26 6:16 UTC (permalink / raw)
To: Venki Pallipadi; +Cc: linux-acpi, abelay
From: Len Brown <len.brown@intel.com>
Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this
processor_idle.c | 2006 ++++++++++++++++++++++++++-----------------
1 file changed, 1219 insertions(+), 787 deletions(-)
to this:
processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 458 insertions(+), 44 deletions(-)
...for the purpose of making the cpuilde patch less invasive
and easier to review.
no functional changes. build tested only.
Signed-off-by: Len Brown <len.brown@intel.com>
---
processor_idle.c | 1122 +++++++++++++++++++++++++++----------------------------
1 file changed, 552 insertions(+), 570 deletions(-)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index d93f84f..2d4a582 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -63,6 +63,15 @@
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_idle");
#define ACPI_PROCESSOR_FILE_POWER "power"
+#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+#ifndef CONFIG_CPU_IDLE
+#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
+static void (*pm_idle_save) (void) __read_mostly;
+#else
+#define C2_OVERHEAD 1 /* 1us */
+#define C3_OVERHEAD 1 /* 1us */
+#endif
#define PM_TIMER_TICKS_TO_US(p) (((p) * 1000)/(PM_TIMER_FREQUENCY/1000))
static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
@@ -71,8 +80,16 @@ static unsigned int nocst __read_mostly;
module_param(nocst, uint, 0000);
#ifndef CONFIG_CPU_IDLE
-
-#define US_TO_PM_TIMER_TICKS(t) ((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+/*
+ * bm_history -- bit-mask with a bit per jiffy of bus-master activity
+ * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
+ * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
+ * 100 HZ: 0x0000000F: 4 jiffies = 40ms
+ * reduce history for more aggressive entry into C3
+ */
+static unsigned int bm_history __read_mostly =
+ (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
+module_param(bm_history, uint, 0644);
static int acpi_processor_set_power_policy(struct acpi_processor *pr);
@@ -159,6 +176,101 @@ static struct dmi_system_id __cpuinitdata processor_power_dmi_table[] = {
{},
};
+static inline u32 ticks_elapsed(u32 t1, u32 t2)
+{
+ if (t2 >= t1)
+ return (t2 - t1);
+ else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
+ return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
+ else
+ return ((0xFFFFFFFF - t1) + t2);
+}
+
+static inline u32 ticks_elapsed_in_us(u32 t1, u32 t2)
+{
+ if (t2 >= t1)
+ return PM_TIMER_TICKS_TO_US(t2 - t1);
+ else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
+ return PM_TIMER_TICKS_TO_US(((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
+ else
+ return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
+}
+
+#ifndef CONFIG_CPU_IDLE
+
+static void
+acpi_processor_power_activate(struct acpi_processor *pr,
+ struct acpi_processor_cx *new)
+{
+ struct acpi_processor_cx *old;
+
+ if (!pr || !new)
+ return;
+
+ old = pr->power.state;
+
+ if (old)
+ old->promotion.count = 0;
+ new->demotion.count = 0;
+
+ /* Cleanup from old state. */
+ if (old) {
+ switch (old->type) {
+ case ACPI_STATE_C3:
+ /* Disable bus master reload */
+ if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
+ break;
+ }
+ }
+
+ /* Prepare to use new state. */
+ switch (new->type) {
+ case ACPI_STATE_C3:
+ /* Enable bus master reload */
+ if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
+ break;
+ }
+
+ pr->power.state = new;
+
+ return;
+}
+
+static void acpi_safe_halt(void)
+{
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (!need_resched())
+ safe_halt();
+ current_thread_info()->status |= TS_POLLING;
+}
+
+static atomic_t c3_cpu_count;
+
+/* Common C-state entry for C2, C3, .. */
+static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
+{
+ if (cstate->space_id == ACPI_CSTATE_FFH) {
+ /* Call into architectural FFH based C-state */
+ acpi_processor_ffh_cstate_enter(cstate);
+ } else {
+ int unused;
+ /* IO port based C-state */
+ inb(cstate->address);
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ }
+}
+#endif /* !CONFIG_CPU_IDLE */
+
#ifdef ARCH_APICTIMER_STOPS_ON_C3
/*
@@ -234,6 +346,389 @@ static void acpi_state_timer_broadcast(struct acpi_processor *pr,
}
#endif
+#ifndef CONFIG_CPU_IDLE
+
+static void acpi_processor_idle(void)
+{
+ struct acpi_processor *pr = NULL;
+ struct acpi_processor_cx *cx = NULL;
+ struct acpi_processor_cx *next_state = NULL;
+ int sleep_ticks = 0;
+ u32 t1, t2 = 0;
+
+ /*
+ * Interrupts must be disabled during bus mastering calculations and
+ * for C2/C3 transitions.
+ */
+ local_irq_disable();
+
+ pr = processors[smp_processor_id()];
+ if (!pr) {
+ local_irq_enable();
+ return;
+ }
+
+ /*
+ * Check whether we truly need to go idle, or should
+ * reschedule:
+ */
+ if (unlikely(need_resched())) {
+ local_irq_enable();
+ return;
+ }
+
+ cx = pr->power.state;
+ if (!cx) {
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+ return;
+ }
+
+ /*
+ * Check BM Activity
+ * -----------------
+ * Check for bus mastering activity (if required), record, and check
+ * for demotion.
+ */
+ if (pr->flags.bm_check) {
+ u32 bm_status = 0;
+ unsigned long diff = jiffies - pr->power.bm_check_timestamp;
+
+ if (diff > 31)
+ diff = 31;
+
+ pr->power.bm_activity <<= diff;
+
+ acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
+ if (bm_status) {
+ pr->power.bm_activity |= 0x1;
+ acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
+ }
+ /*
+ * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
+ * the true state of bus mastering activity; forcing us to
+ * manually check the BMIDEA bit of each IDE channel.
+ */
+ else if (errata.piix4.bmisx) {
+ if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
+ || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
+ pr->power.bm_activity |= 0x1;
+ }
+
+ pr->power.bm_check_timestamp = jiffies;
+
+ /*
+ * If bus mastering is or was active this jiffy, demote
+ * to avoid a faulty transition. Note that the processor
+ * won't enter a low-power state during this call (to this
+ * function) but should upon the next.
+ *
+ * TBD: A better policy might be to fallback to the demotion
+ * state (use it for this quantum only) istead of
+ * demoting -- and rely on duration as our sole demotion
+ * qualification. This may, however, introduce DMA
+ * issues (e.g. floppy DMA transfer overrun/underrun).
+ */
+ if ((pr->power.bm_activity & 0x1) &&
+ cx->demotion.threshold.bm) {
+ local_irq_enable();
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /*
+ * Check for P_LVL2_UP flag before entering C2 and above on
+ * an SMP system. We do it here instead of doing it at _CST/P_LVL
+ * detection phase, to work cleanly with logical CPU hotplug.
+ */
+ if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
+ cx = &pr->power.states[ACPI_STATE_C1];
+#endif
+
+ /*
+ * Sleep:
+ * ------
+ * Invoke the current Cx state to put the processor to sleep.
+ */
+ if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
+ current_thread_info()->status &= ~TS_POLLING;
+ /*
+ * TS_POLLING-cleared state must be visible before we
+ * test NEED_RESCHED:
+ */
+ smp_mb();
+ if (need_resched()) {
+ current_thread_info()->status |= TS_POLLING;
+ local_irq_enable();
+ return;
+ }
+ }
+
+ switch (cx->type) {
+
+ case ACPI_STATE_C1:
+ /*
+ * Invoke C1.
+ * Use the appropriate idle routine, the one that would
+ * be used without acpi C-states.
+ */
+ if (pm_idle_save)
+ pm_idle_save();
+ else
+ acpi_safe_halt();
+
+ /*
+ * TBD: Can't get time duration while in C1, as resumes
+ * go to an ISR rather than here. Need to instrument
+ * base interrupt handler.
+ */
+ sleep_ticks = 0xFFFFFFFF;
+ break;
+
+ case ACPI_STATE_C2:
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Invoke C2 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable("possible TSC halt in C2");
+#endif
+ /* Re-enable interrupts */
+ local_irq_enable();
+ current_thread_info()->status |= TS_POLLING;
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks =
+ ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ case ACPI_STATE_C3:
+
+ /*
+ * disable bus master
+ * bm_check implies we need ARB_DIS
+ * !bm_check implies we need cache flush
+ * bm_control implies whether we can do ARB_DIS
+ *
+ * That leaves a case where bm_check is set and bm_control is
+ * not set. In that case we cannot do much, we enter C3
+ * without doing anything.
+ */
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ if (atomic_inc_return(&c3_cpu_count) ==
+ num_online_cpus()) {
+ /*
+ * All CPUs are trying to go to C3
+ * Disable bus master arbitration
+ */
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
+ }
+ } else if (!pr->flags.bm_check) {
+ /* SMP with no shared cache... Invalidate cache */
+ ACPI_FLUSH_CPU_CACHE();
+ }
+
+ /* Get start time (ticks) */
+ t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ /* Invoke C3 */
+ acpi_state_timer_broadcast(pr, cx, 1);
+ acpi_cstate_enter(cx);
+ /* Get end time (ticks) */
+ t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+ if (pr->flags.bm_check && pr->flags.bm_control) {
+ /* Enable bus master arbitration */
+ atomic_dec(&c3_cpu_count);
+ acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
+ }
+
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable("TSC halts in C3");
+#endif
+ /* Re-enable interrupts */
+ local_irq_enable();
+ current_thread_info()->status |= TS_POLLING;
+ /* Compute time (ticks) that we were actually asleep */
+ sleep_ticks =
+ ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
+ acpi_state_timer_broadcast(pr, cx, 0);
+ break;
+
+ default:
+ local_irq_enable();
+ return;
+ }
+ cx->usage++;
+ if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+ cx->time += sleep_ticks;
+
+ next_state = pr->power.state;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ /* Don't do promotion/demotion */
+ if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
+ !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
+ next_state = cx;
+ goto end;
+ }
+#endif
+
+ /*
+ * Promotion?
+ * ----------
+ * Track the number of longs (time asleep is greater than threshold)
+ * and promote when the count threshold is reached. Note that bus
+ * mastering activity may prevent promotions.
+ * Do not promote above max_cstate.
+ */
+ if (cx->promotion.state &&
+ ((cx->promotion.state - pr->power.states) <= max_cstate)) {
+ if (sleep_ticks > cx->promotion.threshold.ticks &&
+ cx->promotion.state->latency <= system_latency_constraint()) {
+ cx->promotion.count++;
+ cx->demotion.count = 0;
+ if (cx->promotion.count >=
+ cx->promotion.threshold.count) {
+ if (pr->flags.bm_check) {
+ if (!
+ (pr->power.bm_activity & cx->
+ promotion.threshold.bm)) {
+ next_state =
+ cx->promotion.state;
+ goto end;
+ }
+ } else {
+ next_state = cx->promotion.state;
+ goto end;
+ }
+ }
+ }
+ }
+
+ /*
+ * Demotion?
+ * ---------
+ * Track the number of shorts (time asleep is less than time threshold)
+ * and demote when the usage threshold is reached.
+ */
+ if (cx->demotion.state) {
+ if (sleep_ticks < cx->demotion.threshold.ticks) {
+ cx->demotion.count++;
+ cx->promotion.count = 0;
+ if (cx->demotion.count >= cx->demotion.threshold.count) {
+ next_state = cx->demotion.state;
+ goto end;
+ }
+ }
+ }
+
+ end:
+ /*
+ * Demote if current state exceeds max_cstate
+ * or if the latency of the current state is unacceptable
+ */
+ if ((pr->power.state - pr->power.states) > max_cstate ||
+ pr->power.state->latency > system_latency_constraint()) {
+ if (cx->demotion.state)
+ next_state = cx->demotion.state;
+ }
+
+ /*
+ * New Cx State?
+ * -------------
+ * If we're going to start using a new Cx state we must clean up
+ * from the previous and prepare to use the new.
+ */
+ if (next_state != pr->power.state)
+ acpi_processor_power_activate(pr, next_state);
+}
+
+static int acpi_processor_set_power_policy(struct acpi_processor *pr)
+{
+ unsigned int i;
+ unsigned int state_is_set = 0;
+ struct acpi_processor_cx *lower = NULL;
+ struct acpi_processor_cx *higher = NULL;
+ struct acpi_processor_cx *cx;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ /*
+ * This function sets the default Cx state policy (OS idle handler).
+ * Our scheme is to promote quickly to C2 but more conservatively
+ * to C3. We're favoring C2 for its characteristics of low latency
+ * (quick response), good power savings, and ability to allow bus
+ * mastering activity. Note that the Cx state policy is completely
+ * customizable and can be altered dynamically.
+ */
+
+ /* startup state */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (!state_is_set)
+ pr->power.state = cx;
+ state_is_set++;
+ break;
+ }
+
+ if (!state_is_set)
+ return -ENODEV;
+
+ /* demotion */
+ for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (lower) {
+ cx->demotion.state = lower;
+ cx->demotion.threshold.ticks = cx->latency_ticks;
+ cx->demotion.threshold.count = 1;
+ if (cx->type == ACPI_STATE_C3)
+ cx->demotion.threshold.bm = bm_history;
+ }
+
+ lower = cx;
+ }
+
+ /* promotion */
+ for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
+ cx = &pr->power.states[i];
+ if (!cx->valid)
+ continue;
+
+ if (higher) {
+ cx->promotion.state = higher;
+ cx->promotion.threshold.ticks = cx->latency_ticks;
+ if (cx->type >= ACPI_STATE_C2)
+ cx->promotion.threshold.count = 4;
+ else
+ cx->promotion.threshold.count = 10;
+ if (higher->type == ACPI_STATE_C3)
+ cx->promotion.threshold.bm = bm_history;
+ }
+
+ higher = cx;
+ }
+
+ return 0;
+}
+#endif /* !CONFIG_CPU_IDLE */
static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)
{
@@ -453,10 +948,10 @@ static void acpi_processor_power_verify_c2(struct acpi_processor_cx *cx)
*/
cx->valid = 1;
-#ifdef CONFIG_CPU_IDLE
- cx->latency_ticks = cx->latency;
-#else
+#ifndef CONFIG_CPU_IDLE
cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#else
+ cx->latency_ticks = cx->latency;
#endif
return;
@@ -532,10 +1027,10 @@ static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
*/
cx->valid = 1;
-#ifdef CONFIG_CPU_IDLE
- cx->latency_ticks = cx->latency;
-#else
+#ifndef CONFIG_CPU_IDLE
cx->latency_ticks = US_TO_PM_TIMER_TICKS(cx->latency);
+#else
+ cx->latency_ticks = cx->latency;
#endif
return;
@@ -711,30 +1206,61 @@ static const struct file_operations acpi_processor_power_fops = {
.release = single_release,
};
-static inline u32 ticks_elapsed_in_us(u32 t1, u32 t2)
+#ifndef CONFIG_CPU_IDLE
+
+int acpi_processor_cst_has_changed(struct acpi_processor *pr)
{
- if (t2 >= t1)
- return PM_TIMER_TICKS_TO_US(t2 - t1);
- else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
- return PM_TIMER_TICKS_TO_US(((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
- else
- return PM_TIMER_TICKS_TO_US((0xFFFFFFFF - t1) + t2);
+ int result = 0;
+
+
+ if (!pr)
+ return -EINVAL;
+
+ if (nocst) {
+ return -ENODEV;
+ }
+
+ if (!pr->flags.power_setup_done)
+ return -ENODEV;
+
+ /* Fall back to the default idle loop */
+ pm_idle = pm_idle_save;
+ synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
+
+ pr->flags.power = 0;
+ result = acpi_processor_get_power_info(pr);
+ if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
+ pm_idle = acpi_processor_idle;
+
+ return result;
}
-static inline u32 ticks_elapsed(u32 t1, u32 t2)
+#ifdef CONFIG_SMP
+static void smp_callback(void *v)
{
- if (t2 >= t1)
- return (t2 - t1);
- else if (!(acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER))
- return (((0x00FFFFFF - t1) + t2) & 0x00FFFFFF);
- else
- return ((0xFFFFFFFF - t1) + t2);
+ /* we already woke the CPU up, nothing more to do */
}
-#ifdef CONFIG_CPU_IDLE
+/*
+ * This function gets called when a part of the kernel has a new latency
+ * requirement. This means we need to get all processors out of their C-state,
+ * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
+ * wakes them all right up.
+ */
+static int acpi_processor_latency_notify(struct notifier_block *b,
+ unsigned long l, void *v)
+{
+ smp_call_function(smp_callback, NULL, 0, 1);
+ return NOTIFY_OK;
+}
-#define C2_OVERHEAD 1 /* 1us */
-#define C3_OVERHEAD 1 /* 1us */
+static struct notifier_block acpi_processor_latency_notifier = {
+ .notifier_call = acpi_processor_latency_notify,
+};
+
+#endif
+
+#else /* CONFIG_CPU_IDLE */
/**
* acpi_idle_bm_check - checks if bus master activity was detected
@@ -1084,551 +1610,7 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr)
return ret;
}
-#else
-
-/*
- * This code provides the older acpi behaviour when cpuidle is not configured.
- * This will go away once CPU_IDLE has been fully integrated into the mainline
- * kernel. -- Venki --
- */
-#define C2_OVERHEAD 4 /* 1us (3.579 ticks per us) */
-#define C3_OVERHEAD 4 /* 1us (3.579 ticks per us) */
-static void (*pm_idle_save) (void) __read_mostly;
-
-/*
- * bm_history -- bit-mask with a bit per jiffy of bus-master activity
- * 1000 HZ: 0xFFFFFFFF: 32 jiffies = 32ms
- * 800 HZ: 0xFFFFFFFF: 32 jiffies = 40ms
- * 100 HZ: 0x0000000F: 4 jiffies = 40ms
- * reduce history for more aggressive entry into C3
- */
-static unsigned int bm_history __read_mostly =
- (HZ >= 800 ? 0xFFFFFFFF : ((1U << (HZ / 25)) - 1));
-module_param(bm_history, uint, 0644);
-
-static void
-acpi_processor_power_activate(struct acpi_processor *pr,
- struct acpi_processor_cx *new)
-{
- struct acpi_processor_cx *old;
-
- if (!pr || !new)
- return;
-
- old = pr->power.state;
-
- if (old)
- old->promotion.count = 0;
- new->demotion.count = 0;
-
- /* Cleanup from old state. */
- if (old) {
- switch (old->type) {
- case ACPI_STATE_C3:
- /* Disable bus master reload */
- if (new->type != ACPI_STATE_C3 && pr->flags.bm_check)
- acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
- break;
- }
- }
-
- /* Prepare to use new state. */
- switch (new->type) {
- case ACPI_STATE_C3:
- /* Enable bus master reload */
- if (old->type != ACPI_STATE_C3 && pr->flags.bm_check)
- acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 1);
- break;
- }
-
- pr->power.state = new;
-
- return;
-}
-
-static void acpi_safe_halt(void)
-{
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
- if (!need_resched())
- safe_halt();
- current_thread_info()->status |= TS_POLLING;
-}
-
-static atomic_t c3_cpu_count;
-
-/* Common C-state entry for C2, C3, .. */
-static void acpi_cstate_enter(struct acpi_processor_cx *cstate)
-{
- if (cstate->space_id == ACPI_CSTATE_FFH) {
- /* Call into architectural FFH based C-state */
- acpi_processor_ffh_cstate_enter(cstate);
- } else {
- int unused;
- /* IO port based C-state */
- inb(cstate->address);
- /* Dummy wait op - must do something useless after P_LVL2 read
- because chipsets cannot guarantee that STPCLK# signal
- gets asserted in time to freeze execution properly. */
- unused = inl(acpi_gbl_FADT.xpm_timer_block.address);
- }
-}
-
-static void acpi_processor_idle(void)
-{
- struct acpi_processor *pr = NULL;
- struct acpi_processor_cx *cx = NULL;
- struct acpi_processor_cx *next_state = NULL;
- int sleep_ticks = 0;
- u32 t1, t2 = 0;
-
- /*
- * Interrupts must be disabled during bus mastering calculations and
- * for C2/C3 transitions.
- */
- local_irq_disable();
-
- pr = processors[smp_processor_id()];
- if (!pr) {
- local_irq_enable();
- return;
- }
-
- /*
- * Check whether we truly need to go idle, or should
- * reschedule:
- */
- if (unlikely(need_resched())) {
- local_irq_enable();
- return;
- }
-
- cx = pr->power.state;
- if (!cx) {
- if (pm_idle_save)
- pm_idle_save();
- else
- acpi_safe_halt();
- return;
- }
-
- /*
- * Check BM Activity
- * -----------------
- * Check for bus mastering activity (if required), record, and check
- * for demotion.
- */
- if (pr->flags.bm_check) {
- u32 bm_status = 0;
- unsigned long diff = jiffies - pr->power.bm_check_timestamp;
-
- if (diff > 31)
- diff = 31;
-
- pr->power.bm_activity <<= diff;
-
- acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
- if (bm_status) {
- pr->power.bm_activity |= 0x1;
- acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
- }
- /*
- * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
- * the true state of bus mastering activity; forcing us to
- * manually check the BMIDEA bit of each IDE channel.
- */
- else if (errata.piix4.bmisx) {
- if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
- || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
- pr->power.bm_activity |= 0x1;
- }
-
- pr->power.bm_check_timestamp = jiffies;
-
- /*
- * If bus mastering is or was active this jiffy, demote
- * to avoid a faulty transition. Note that the processor
- * won't enter a low-power state during this call (to this
- * function) but should upon the next.
- *
- * TBD: A better policy might be to fallback to the demotion
- * state (use it for this quantum only) istead of
- * demoting -- and rely on duration as our sole demotion
- * qualification. This may, however, introduce DMA
- * issues (e.g. floppy DMA transfer overrun/underrun).
- */
- if ((pr->power.bm_activity & 0x1) &&
- cx->demotion.threshold.bm) {
- local_irq_enable();
- next_state = cx->demotion.state;
- goto end;
- }
- }
-
-#ifdef CONFIG_HOTPLUG_CPU
- /*
- * Check for P_LVL2_UP flag before entering C2 and above on
- * an SMP system. We do it here instead of doing it at _CST/P_LVL
- * detection phase, to work cleanly with logical CPU hotplug.
- */
- if ((cx->type != ACPI_STATE_C1) && (num_online_cpus() > 1) &&
- !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))
- cx = &pr->power.states[ACPI_STATE_C1];
-#endif
-
- /*
- * Sleep:
- * ------
- * Invoke the current Cx state to put the processor to sleep.
- */
- if (cx->type == ACPI_STATE_C2 || cx->type == ACPI_STATE_C3) {
- current_thread_info()->status &= ~TS_POLLING;
- /*
- * TS_POLLING-cleared state must be visible before we
- * test NEED_RESCHED:
- */
- smp_mb();
- if (need_resched()) {
- current_thread_info()->status |= TS_POLLING;
- local_irq_enable();
- return;
- }
- }
-
- switch (cx->type) {
-
- case ACPI_STATE_C1:
- /*
- * Invoke C1.
- * Use the appropriate idle routine, the one that would
- * be used without acpi C-states.
- */
- if (pm_idle_save)
- pm_idle_save();
- else
- acpi_safe_halt();
-
- /*
- * TBD: Can't get time duration while in C1, as resumes
- * go to an ISR rather than here. Need to instrument
- * base interrupt handler.
- *
- * Note: the TSC better not stop in C1, sched_clock() will
- * skew otherwise.
- */
- sleep_ticks = 0xFFFFFFFF;
- break;
-
- case ACPI_STATE_C2:
- /* Get start time (ticks) */
- t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- /* Tell the scheduler that we are going deep-idle: */
- sched_clock_idle_sleep_event();
- /* Invoke C2 */
- acpi_state_timer_broadcast(pr, cx, 1);
- acpi_cstate_enter(cx);
- /* Get end time (ticks) */
- t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
-
-#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
- /* TSC halts in C2, so notify users */
- mark_tsc_unstable("possible TSC halt in C2");
-#endif
- /* Compute time (ticks) that we were actually asleep */
- sleep_ticks = ticks_elapsed(t1, t2);
-
- /* Tell the scheduler how much we idled: */
- sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
-
- /* Re-enable interrupts */
- local_irq_enable();
- /* Do not account our idle-switching overhead: */
- sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
-
- current_thread_info()->status |= TS_POLLING;
- acpi_state_timer_broadcast(pr, cx, 0);
- break;
-
- case ACPI_STATE_C3:
- /*
- * disable bus master
- * bm_check implies we need ARB_DIS
- * !bm_check implies we need cache flush
- * bm_control implies whether we can do ARB_DIS
- *
- * That leaves a case where bm_check is set and bm_control is
- * not set. In that case we cannot do much, we enter C3
- * without doing anything.
- */
- if (pr->flags.bm_check && pr->flags.bm_control) {
- if (atomic_inc_return(&c3_cpu_count) ==
- num_online_cpus()) {
- /*
- * All CPUs are trying to go to C3
- * Disable bus master arbitration
- */
- acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
- }
- } else if (!pr->flags.bm_check) {
- /* SMP with no shared cache... Invalidate cache */
- ACPI_FLUSH_CPU_CACHE();
- }
-
- /* Get start time (ticks) */
- t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- /* Invoke C3 */
- acpi_state_timer_broadcast(pr, cx, 1);
- /* Tell the scheduler that we are going deep-idle: */
- sched_clock_idle_sleep_event();
- acpi_cstate_enter(cx);
- /* Get end time (ticks) */
- t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
- if (pr->flags.bm_check && pr->flags.bm_control) {
- /* Enable bus master arbitration */
- atomic_dec(&c3_cpu_count);
- acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
- }
-
-#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
- /* TSC halts in C3, so notify users */
- mark_tsc_unstable("TSC halts in C3");
-#endif
- /* Compute time (ticks) that we were actually asleep */
- sleep_ticks = ticks_elapsed(t1, t2);
- /* Tell the scheduler how much we idled: */
- sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
-
- /* Re-enable interrupts */
- local_irq_enable();
- /* Do not account our idle-switching overhead: */
- sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
-
- current_thread_info()->status |= TS_POLLING;
- acpi_state_timer_broadcast(pr, cx, 0);
- break;
-
- default:
- local_irq_enable();
- return;
- }
- cx->usage++;
- if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
- cx->time += sleep_ticks;
-
- next_state = pr->power.state;
-
-#ifdef CONFIG_HOTPLUG_CPU
- /* Don't do promotion/demotion */
- if ((cx->type == ACPI_STATE_C1) && (num_online_cpus() > 1) &&
- !pr->flags.has_cst && !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED)) {
- next_state = cx;
- goto end;
- }
-#endif
-
- /*
- * Promotion?
- * ----------
- * Track the number of longs (time asleep is greater than threshold)
- * and promote when the count threshold is reached. Note that bus
- * mastering activity may prevent promotions.
- * Do not promote above max_cstate.
- */
- if (cx->promotion.state &&
- ((cx->promotion.state - pr->power.states) <= max_cstate)) {
- if (sleep_ticks > cx->promotion.threshold.ticks &&
- cx->promotion.state->latency <= system_latency_constraint()) {
- cx->promotion.count++;
- cx->demotion.count = 0;
- if (cx->promotion.count >=
- cx->promotion.threshold.count) {
- if (pr->flags.bm_check) {
- if (!
- (pr->power.bm_activity & cx->
- promotion.threshold.bm)) {
- next_state =
- cx->promotion.state;
- goto end;
- }
- } else {
- next_state = cx->promotion.state;
- goto end;
- }
- }
- }
- }
-
- /*
- * Demotion?
- * ---------
- * Track the number of shorts (time asleep is less than time threshold)
- * and demote when the usage threshold is reached.
- */
- if (cx->demotion.state) {
- if (sleep_ticks < cx->demotion.threshold.ticks) {
- cx->demotion.count++;
- cx->promotion.count = 0;
- if (cx->demotion.count >= cx->demotion.threshold.count) {
- next_state = cx->demotion.state;
- goto end;
- }
- }
- }
-
- end:
- /*
- * Demote if current state exceeds max_cstate
- * or if the latency of the current state is unacceptable
- */
- if ((pr->power.state - pr->power.states) > max_cstate ||
- pr->power.state->latency > system_latency_constraint()) {
- if (cx->demotion.state)
- next_state = cx->demotion.state;
- }
-
- /*
- * New Cx State?
- * -------------
- * If we're going to start using a new Cx state we must clean up
- * from the previous and prepare to use the new.
- */
- if (next_state != pr->power.state)
- acpi_processor_power_activate(pr, next_state);
-}
-
-static int acpi_processor_set_power_policy(struct acpi_processor *pr)
-{
- unsigned int i;
- unsigned int state_is_set = 0;
- struct acpi_processor_cx *lower = NULL;
- struct acpi_processor_cx *higher = NULL;
- struct acpi_processor_cx *cx;
-
-
- if (!pr)
- return -EINVAL;
-
- /*
- * This function sets the default Cx state policy (OS idle handler).
- * Our scheme is to promote quickly to C2 but more conservatively
- * to C3. We're favoring C2 for its characteristics of low latency
- * (quick response), good power savings, and ability to allow bus
- * mastering activity. Note that the Cx state policy is completely
- * customizable and can be altered dynamically.
- */
-
- /* startup state */
- for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (!state_is_set)
- pr->power.state = cx;
- state_is_set++;
- break;
- }
-
- if (!state_is_set)
- return -ENODEV;
-
- /* demotion */
- for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (lower) {
- cx->demotion.state = lower;
- cx->demotion.threshold.ticks = cx->latency_ticks;
- cx->demotion.threshold.count = 1;
- if (cx->type == ACPI_STATE_C3)
- cx->demotion.threshold.bm = bm_history;
- }
-
- lower = cx;
- }
-
- /* promotion */
- for (i = (ACPI_PROCESSOR_MAX_POWER - 1); i > 0; i--) {
- cx = &pr->power.states[i];
- if (!cx->valid)
- continue;
-
- if (higher) {
- cx->promotion.state = higher;
- cx->promotion.threshold.ticks = cx->latency_ticks;
- if (cx->type >= ACPI_STATE_C2)
- cx->promotion.threshold.count = 4;
- else
- cx->promotion.threshold.count = 10;
- if (higher->type == ACPI_STATE_C3)
- cx->promotion.threshold.bm = bm_history;
- }
-
- higher = cx;
- }
-
- return 0;
-}
-
-int acpi_processor_cst_has_changed(struct acpi_processor *pr)
-{
- int result = 0;
-
-
- if (!pr)
- return -EINVAL;
-
- if (nocst) {
- return -ENODEV;
- }
-
- if (!pr->flags.power_setup_done)
- return -ENODEV;
-
- /* Fall back to the default idle loop */
- pm_idle = pm_idle_save;
- synchronize_sched(); /* Relies on interrupts forcing exit from idle. */
-
- pr->flags.power = 0;
- result = acpi_processor_get_power_info(pr);
- if ((pr->flags.power == 1) && (pr->flags.power_setup_done))
- pm_idle = acpi_processor_idle;
-
- return result;
-}
-
-#ifdef CONFIG_SMP
-static void smp_callback(void *v)
-{
- /* we already woke the CPU up, nothing more to do */
-}
-
-/*
- * This function gets called when a part of the kernel has a new latency
- * requirement. This means we need to get all processors out of their C-state,
- * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
- * wakes them all right up.
- */
-static int acpi_processor_latency_notify(struct notifier_block *b,
- unsigned long l, void *v)
-{
- smp_call_function(smp_callback, NULL, 0, 1);
- return NOTIFY_OK;
-}
-
-static struct notifier_block acpi_processor_latency_notifier = {
- .notifier_call = acpi_processor_latency_notify,
-};
-
-#endif
-
-#endif
+#endif /* CONFIG_CPU_IDLE */
int __cpuinit acpi_processor_power_init(struct acpi_processor *pr,
struct acpi_device *device)
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2007-09-26 6:16 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-09-13 20:40 [PATCH] Retain old acpi policy for !CONFIG_CPU_IDLE Venki Pallipadi
2007-09-22 3:00 ` Len Brown
2007-09-25 22:13 ` Len Brown
2007-09-26 6:16 ` [PATCH] cpuidle: reduce diff size Len Brown
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