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Message-ID: <17474563.tpu6u1dKOa@vostro.rjw.lan>
Date: Sun, 10 May 2015 01:09:28 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...uxtronix.de>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>
Subject: [PATCH] PM / tick: Add tracepoints for suspend-to-idle diagnostics
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Add suspend/resume tracepoints to tick_freeze() and tick_unfreeze()
to catch when timekeeping is suspended and resumed during suspend-to-idle
so as to be able to check whether or not we enter the "frozen" state
and to measure the time spent in it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
kernel/time/tick-common.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
Index: linux-pm/kernel/time/tick-common.c
===================================================================
--- linux-pm.orig/kernel/time/tick-common.c
+++ linux-pm/kernel/time/tick-common.c
@@ -19,6 +19,7 @@
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/module.h>
+#include <trace/events/power.h>
#include <asm/irq_regs.h>
@@ -457,10 +458,13 @@ void tick_freeze(void)
raw_spin_lock(&tick_freeze_lock);
tick_freeze_depth++;
- if (tick_freeze_depth == num_online_cpus())
+ if (tick_freeze_depth == num_online_cpus()) {
+ trace_suspend_resume(TPS("timekeeping_freeze"),
+ smp_processor_id(), true);
timekeeping_suspend();
- else
+ } else {
tick_suspend_local();
+ }
raw_spin_unlock(&tick_freeze_lock);
}
@@ -478,10 +482,13 @@ void tick_unfreeze(void)
{
raw_spin_lock(&tick_freeze_lock);
- if (tick_freeze_depth == num_online_cpus())
+ if (tick_freeze_depth == num_online_cpus()) {
timekeeping_resume();
- else
+ trace_suspend_resume(TPS("timekeeping_freeze"),
+ smp_processor_id(), false);
+ } else {
tick_resume_local();
+ }
tick_freeze_depth--;
--
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