[PATCH 10 update] PM: Measure suspend and resume times for individual devices

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Monday 31 August 2009, Rafael J. Wysocki wrote:
> On Monday 31 August 2009, Ingo Molnar wrote:
...
> > > > Hm, these CPP macros are rather ugly. Why is there a need for 
> > > > the TIMER_DECLARE() wrapper - if a proper inline function is 
> > > > used there's no need for that.
> > > 
> > > I need a variable to be declared so that I can save the "start" 
> > > timestamp in it.  I don't need the variable if DEBUG is unset, 
> > > though.
> > > 
> > > How would you do that without using a macro?  Or #ifdef #endif 
> > > block that would be uglier IMO (which is why I didn't do that)?
> > 
> > Well, why not use an inline function like i suggested? [which does 
> > nothing in the !enabled case] You can keep the local variable always 
> > defined.
> 
> Well, I used the macros _exactly_ because I didn't want to keep the local
> variable always defined.
> 
> Now, if you think that adding several useless bytes to the stack frame is OK,
> perhaps it can be always defined.  However, IMnsHO that would be
> (a) confusing (why define a variable you don't use) and (b) wasteful.
> 
> Perhaps the names of the macros should be directly related to debugging?

Something like in the patch below, maybe?

Best,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM: Measure suspend and resume times for individual devices

If verbose PM debugging is enabled, measure and print the time of
suspending and resuming of individual devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/base/power/main.c |   51 +++++++++++++++++++++++++++++++++++++++++-----
 kernel/power/swsusp.c     |    2 -
 2 files changed, 47 insertions(+), 6 deletions(-)

Index: linux-2.6/drivers/base/power/main.c
===================================================================
--- linux-2.6.orig/drivers/base/power/main.c
+++ linux-2.6/drivers/base/power/main.c
@@ -442,11 +442,11 @@ static bool pm_op_started(struct device 
  */
 int pm_time_elapsed(struct timeval *start, struct timeval *stop)
 {
-	s64 elapsed_centisecs64;
+	s64 elapsed_msecs64;
 
-	elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
-	do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
-	return elapsed_centisecs64;
+	elapsed_msecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
+	do_div(elapsed_msecs64, NSEC_PER_SEC / 1000);
+	return elapsed_msecs64;
 }
 
 static char *pm_verb(int event)
@@ -476,7 +476,7 @@ static char *pm_verb(int event)
 static void dpm_show_time(struct timeval *start, struct timeval *stop,
 			  pm_message_t state, const char *info)
 {
-	int centisecs = pm_time_elapsed(start, stop);
+	int centisecs = pm_time_elapsed(start, stop) / 10;
 
 	printk(KERN_INFO "PM: %s%s%s of devices complete in %d.%02d seconds\n",
 		info ? info : "", info ? " " : "", pm_verb(state.event),
@@ -497,6 +497,33 @@ static void pm_dev_err(struct device *de
 		kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 }
 
+#ifdef DEBUG
+static void device_show_time(struct timeval *start, struct device *dev,
+			     pm_message_t state, char *info)
+{
+	struct timeval stop;
+	int msecs;
+
+	do_gettimeofday(&stop);
+	msecs = pm_time_elapsed(start, &stop);
+	dev_dbg(dev, "PID %d: %s%s%s complete in %d.%03d seconds\n",
+		task_pid_nr(current), info ? info : "", info ? " " : "",
+		pm_verb(state.event), msecs / 1000, msecs % 1000);
+}
+
+#define DEBUG_TIMEVAL(tv)	struct timeval tv
+#define DEBUG_TIME_START(tv)	do { \
+		do_gettimeofday(&tv); \
+	} while (0)
+#define DEBUG_TIME_SHOW(tv, dev, state, info)	do { \
+		device_show_time(&tv, dev, state, info); \
+	} while (0)
+#else /* !DEBUG */
+#define DEBUG_TIMEVAL(tv)
+#define DEBUG_TIME_START(tv)	do { } while (0)
+#define DEBUG_TIME_SHOW(tv, dev, state, info)	do { } while (0)
+#endif /* !DEBUG */
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
@@ -510,7 +537,9 @@ static void pm_dev_err(struct device *de
 static int __device_resume_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	DEBUG_TIMEVAL(start);
 
+	DEBUG_TIME_START(start);
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
@@ -523,6 +552,7 @@ static int __device_resume_noirq(struct 
 	wake_up_all(&dev->power.wait_queue);
 
 	TRACE_RESUME(error);
+	DEBUG_TIME_SHOW(start, dev, state, "EARLY");
 	return error;
 }
 
@@ -639,7 +669,9 @@ EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 static int __device_resume(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	DEBUG_TIMEVAL(start);
 
+	DEBUG_TIME_START(start);
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
@@ -681,6 +713,7 @@ static int __device_resume(struct device
 	wake_up_all(&dev->power.wait_queue);
 
 	TRACE_RESUME(error);
+	DEBUG_TIME_SHOW(start, dev, state, NULL);
 	return error;
 }
 
@@ -923,6 +956,9 @@ static pm_message_t resume_event(pm_mess
 static int __device_suspend_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	DEBUG_TIMEVAL(start);
+
+	DEBUG_TIME_START(start);
 
 	if (dev->bus && dev->bus->pm) {
 		pm_dev_dbg(dev, state, "LATE ");
@@ -932,6 +968,7 @@ static int __device_suspend_noirq(struct
 	dev->power.op_complete = true;
 	wake_up_all(&dev->power.wait_queue);
 
+	DEBUG_TIME_SHOW(start, dev, state, "LATE");
 	return error;
 }
 
@@ -1063,6 +1100,9 @@ EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 static int __device_suspend(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	DEBUG_TIMEVAL(start);
+
+	DEBUG_TIME_START(start);
 
 	down(&dev->sem);
 
@@ -1103,6 +1143,7 @@ static int __device_suspend(struct devic
 	dev->power.op_complete = true;
 	wake_up_all(&dev->power.wait_queue);
 
+	DEBUG_TIME_SHOW(start, dev, state, NULL);
 	return error;
 }
 
Index: linux-2.6/kernel/power/swsusp.c
===================================================================
--- linux-2.6.orig/kernel/power/swsusp.c
+++ linux-2.6/kernel/power/swsusp.c
@@ -169,7 +169,7 @@ int swsusp_swap_in_use(void)
 void swsusp_show_speed(struct timeval *start, struct timeval *stop,
 			unsigned nr_pages, char *msg)
 {
-	int centisecs = pm_time_elapsed(start, stop);
+	int centisecs = pm_time_elapsed(start, stop) / 10;
 	int k;
 	int kps;