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tracing, x86, cpuidle: Move the end point of a C state in the power tracer

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The "end of a C state" trace point currently happens before
the code runs that corrects the TSC for having stopped during idle.

The result of this is that the timestamp of the end-of-C-state event
is garbage on cpus where the TSC stops during idle.

This patch moves the end point of the C state to after the timekeeping
engine of the kernel has been corrected.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: fweisbec@gmail.com
Cc: peterz@infradead.org
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20090919133533.139c2a46@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Arjan van de Ven 2009-09-19 13:35:33 +02:00 committed by Ingo Molnar
parent 964a0b3d2b
commit 288f023e70
2 changed files with 2 additions and 3 deletions
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3
arch/x86/kernel/process.c
View file

@ -309,7 +309,6 @@ void default_idle(void)
else else
local_irq_enable(); local_irq_enable();
current_thread_info()->status |= TS_POLLING; current_thread_info()->status |= TS_POLLING;
trace_power_end(0);
} else { } else {
local_irq_enable(); local_irq_enable();
/* loop is done by the caller */ /* loop is done by the caller */
@ -377,7 +376,6 @@ void mwait_idle_with_hints(unsigned long ax, unsigned long cx)
if (!need_resched()) if (!need_resched())
__mwait(ax, cx); __mwait(ax, cx);
} }
trace_power_end(0);
} }
/* Default MONITOR/MWAIT with no hints, used for default C1 state */ /* Default MONITOR/MWAIT with no hints, used for default C1 state */
@ -394,7 +392,6 @@ static void mwait_idle(void)
__sti_mwait(0, 0); __sti_mwait(0, 0);
else else
local_irq_enable(); local_irq_enable();
trace_power_end(0);
} else } else
local_irq_enable(); local_irq_enable();
} }

2
drivers/cpuidle/cpuidle.c
View file

@ -17,6 +17,7 @@
#include <linux/cpuidle.h> #include <linux/cpuidle.h>
#include <linux/ktime.h> #include <linux/ktime.h>
#include <linux/hrtimer.h> #include <linux/hrtimer.h>
#include <trace/events/power.h>
#include "cpuidle.h" #include "cpuidle.h"
@ -91,6 +92,7 @@ static void cpuidle_idle_call(void)
/* give the governor an opportunity to reflect on the outcome */ /* give the governor an opportunity to reflect on the outcome */
if (cpuidle_curr_governor->reflect) if (cpuidle_curr_governor->reflect)
cpuidle_curr_governor->reflect(dev); cpuidle_curr_governor->reflect(dev);
trace_power_end(0);
} }
/** /**