[PATCH 1/5] ACPI / cpuidle: Drop unnecessary calls from ->enter callback routines

From: Rafael J. Wysocki
Date: Thu Jan 29 2015 - 13:08:32 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

acpi_idle_enter_simple() and acpi_idle_enter_bm() don't need to
call sched_clock_idle_sleep/wakeup_event(), because that's taken
care of by the core already. Namely, sched_clock_idle_sleep_event()
is called by tick_nohz_start_idle() called by __tick_nohz_idle_enter()
which in turn is called by tick_nohz_idle_enter() and that is called
by cpu_idle_loop(). Analogously for sched_clock_idle_wakeup_event().

For this reason, drop those calls from the ACPI cpuidle driver's
->enter callback routines.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/acpi/processor_idle.c | 8 --------
1 file changed, 8 deletions(-)

Index: linux-pm/drivers/acpi/processor_idle.c
===================================================================
--- linux-pm.orig/drivers/acpi/processor_idle.c
+++ linux-pm/drivers/acpi/processor_idle.c
@@ -791,12 +791,8 @@ static int acpi_idle_enter_simple(struct
if (cx->type == ACPI_STATE_C3)
ACPI_FLUSH_CPU_CACHE();

- /* Tell the scheduler that we are going deep-idle: */
- sched_clock_idle_sleep_event();
acpi_idle_do_entry(cx);

- sched_clock_idle_wakeup_event(0);
-
lapic_timer_state_broadcast(pr, cx, 0);
return index;
}
@@ -842,8 +838,6 @@ static int acpi_idle_enter_bm(struct cpu

acpi_unlazy_tlb(smp_processor_id());

- /* Tell the scheduler that we are going deep-idle: */
- sched_clock_idle_sleep_event();
/*
* Must be done before busmaster disable as we might need to
* access HPET !
@@ -881,8 +875,6 @@ static int acpi_idle_enter_bm(struct cpu
raw_spin_unlock(&c3_lock);
}

- sched_clock_idle_wakeup_event(0);
-
lapic_timer_state_broadcast(pr, cx, 0);
return index;
}

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