[PATCH 9/9] PM: Measure suspend and resume times for individual devices

["Rafael J. Wysocki" <rjw@xxxxxxx>]

From: Rafael J. Wysocki <rjw@xxxxxxx>

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@xxxxxxx>
---
 drivers/base/power/main.c |   50 +++++++++++++++++++++++++++++++++++++++++-----
 kernel/power/swsusp.c     |    2 -
 2 files changed, 46 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 / MSEC_PER_SEC);
+	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 +497,32 @@ static void pm_dev_err(struct device *de
 		kobject_name(&dev->kobj), pm_verb(state.event), info, error);
 }
 
+#ifdef DEBUG
+static inline void dbg_get_time(struct timeval *start)
+{
+	do_gettimeofday(start);
+}
+
+static void dbg_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);
+}
+
+#else /* !DEBUG */
+static void dbg_get_time(struct timeval *start) {}
+static void dbg_show_time(struct timeval *start, struct device *dev,
+			  pm_message_t state, char *info) {}
+
+#endif /* !DEBUG */
+
 /*------------------------- Resume routines -------------------------*/
 
 /**
@@ -510,7 +536,9 @@ static void pm_dev_err(struct device *de
 static int __device_resume_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	struct timeval start;
 
+	dbg_get_time(&start);
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
@@ -523,6 +551,7 @@ static int __device_resume_noirq(struct 
 	wake_up_all(&dev->power.wait_queue);
 
 	TRACE_RESUME(error);
+	dbg_show_time(&start, dev, state, "EARLY");
 	return error;
 }
 
@@ -639,7 +668,9 @@ EXPORT_SYMBOL_GPL(dpm_resume_noirq);
 static int __device_resume(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	struct timeval start;
 
+	dbg_get_time(&start);
 	TRACE_DEVICE(dev);
 	TRACE_RESUME(0);
 
@@ -681,6 +712,7 @@ static int __device_resume(struct device
 	wake_up_all(&dev->power.wait_queue);
 
 	TRACE_RESUME(error);
+	dbg_show_time(&start, dev, state, NULL);
 	return error;
 }
 
@@ -923,6 +955,9 @@ static pm_message_t resume_event(pm_mess
 static int __device_suspend_noirq(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	struct timeval start;
+
+	dbg_get_time(&start);
 
 	if (dev->bus && dev->bus->pm) {
 		pm_dev_dbg(dev, state, "LATE ");
@@ -932,6 +967,7 @@ static int __device_suspend_noirq(struct
 	dev->power.op_complete = true;
 	wake_up_all(&dev->power.wait_queue);
 
+	dbg_show_time(&start, dev, state, "LATE");
 	return error;
 }
 
@@ -1063,6 +1099,9 @@ EXPORT_SYMBOL_GPL(dpm_suspend_noirq);
 static int __device_suspend(struct device *dev, pm_message_t state)
 {
 	int error = 0;
+	struct timeval start;
+
+	dbg_get_time(&start);
 
 	down(&dev->sem);
 
@@ -1103,6 +1142,7 @@ static int __device_suspend(struct devic
 	dev->power.op_complete = true;
 	wake_up_all(&dev->power.wait_queue);
 
+	dbg_show_time(&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;
 
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