PM / Runtime: Add runtime PM statistics (v3)

In order for PowerTOP to be able to report how well the new runtime PM is working for the various drivers, the kernel needs to export some basic statistics in sysfs. This patch adds two sysfs files in the runtime PM domain that expose the total time a device has been active, and the time a device has been suspended. With this PowerTOP can compute the activity percentage Active %age = 100 * (delta active) / (delta active + delta suspended) and present the information to the user. I've written the PowerTOP code (slated for version 1.12) already, and the output looks like this: Runtime Device Power Management statistics Active Device name 10.0% 06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller [version 2: fix stat update bugs noticed by Alan Stern] [version 3: rebase to -next and move the sysfs declaration] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Runtime: Add runtime PM statistics (v3)
In order for PowerTOP to be able to report how well the new runtime PM is working for the various drivers, the kernel needs to export some basic statistics in sysfs. This patch adds two sysfs files in the runtime PM domain that expose the total time a device has been active, and the time a device has been suspended. With this PowerTOP can compute the activity percentage Active %age = 100 * (delta active) / (delta active + delta suspended) and present the information to the user. I've written the PowerTOP code (slated for version 1.12) already, and the output looks like this: Runtime Device Power Management statistics Active Device name 10.0% 06:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller [version 2: fix stat update bugs noticed by Alan Stern] [version 3: rebase to -next and move the sysfs declaration] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Arjan van de Ven · Rafael J. Wysocki
1 parent 0fcb4eef82
Showing 3 changed files with 83 additions and 7 deletions Side-by-side Diff
drivers/base/power/runtime.c
drivers/base/power/sysfs.c
include/linux/pm.h
@@ -123,7 +123,46 @@
 }
 EXPORT_SYMBOL_GPL(pm_runtime_idle);
  
+
 /**
+ * update_pm_runtime_accounting - Update the time accounting of power states
+ * @dev: Device to update the accounting for
+ *
+ * In order to be able to have time accounting of the various power states
+ * (as used by programs such as PowerTOP to show the effectiveness of runtime
+ * PM), we need to track the time spent in each state.
+ * update_pm_runtime_accounting must be called each time before the
+ * runtime_status field is updated, to account the time in the old state
+ * correctly.
+ */
+void update_pm_runtime_accounting(struct device *dev)
+{
+	unsigned long now = jiffies;
+	int delta;
+
+	delta = now - dev->power.accounting_timestamp;
+
+	if (delta < 0)
+		delta = 0;
+
+	dev->power.accounting_timestamp = now;
+
+	if (dev->power.disable_depth > 0)
+		return;
+
+	if (dev->power.runtime_status == RPM_SUSPENDED)
+		dev->power.suspended_jiffies += delta;
+	else
+		dev->power.active_jiffies += delta;
+}
+
+static void __update_runtime_status(struct device *dev, enum rpm_status status)
+{
+	update_pm_runtime_accounting(dev);
+	dev->power.runtime_status = status;
+}
+
+/**
  * __pm_runtime_suspend - Carry out run-time suspend of given device.
  * @dev: Device to suspend.
  * @from_wq: If set, the function has been called via pm_wq.
@@ -197,7 +236,7 @@
 		goto repeat;
 	}
  
-	dev->power.runtime_status = RPM_SUSPENDING;
+	__update_runtime_status(dev, RPM_SUSPENDING);
 	dev->power.deferred_resume = false;
  
 	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
@@ -228,7 +267,7 @@
 	}
  
 	if (retval) {
-		dev->power.runtime_status = RPM_ACTIVE;
+		__update_runtime_status(dev, RPM_ACTIVE);
 		if (retval == -EAGAIN || retval == -EBUSY) {
 			if (dev->power.timer_expires == 0)
 				notify = true;
@@ -237,7 +276,7 @@
 			pm_runtime_cancel_pending(dev);
 		}
 	} else {
-		dev->power.runtime_status = RPM_SUSPENDED;
+		__update_runtime_status(dev, RPM_SUSPENDED);
 		pm_runtime_deactivate_timer(dev);
  
 		if (dev->parent) {
@@ -381,7 +420,7 @@
 		goto repeat;
 	}
  
-	dev->power.runtime_status = RPM_RESUMING;
+	__update_runtime_status(dev, RPM_RESUMING);
  
 	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) {
 		spin_unlock_irq(&dev->power.lock);
  
@@ -411,10 +450,10 @@
 	}
  
 	if (retval) {
-		dev->power.runtime_status = RPM_SUSPENDED;
+		__update_runtime_status(dev, RPM_SUSPENDED);
 		pm_runtime_cancel_pending(dev);
 	} else {
-		dev->power.runtime_status = RPM_ACTIVE;
+		__update_runtime_status(dev, RPM_ACTIVE);
 		if (parent)
 			atomic_inc(&parent->power.child_count);
 	}
@@ -848,7 +887,7 @@
 	}
  
  out_set:
-	dev->power.runtime_status = status;
+	__update_runtime_status(dev, status);
 	dev->power.runtime_error = 0;
  out:
 	spin_unlock_irqrestore(&dev->power.lock, flags);
@@ -1077,6 +1116,7 @@
 	dev->power.request_pending = false;
 	dev->power.request = RPM_REQ_NONE;
 	dev->power.deferred_resume = false;
+	dev->power.accounting_timestamp = jiffies;
 	INIT_WORK(&dev->power.work, pm_runtime_work);
  
 	dev->power.timer_expires = 0;
@@ -6,6 +6,7 @@
 #include <linux/string.h>
 #include <linux/pm_runtime.h>
 #include <asm/atomic.h>
+#include <linux/jiffies.h>
 #include "power.h"
  
 /*
@@ -111,6 +112,33 @@
  
 static DEVICE_ATTR(control, 0644, control_show, control_store);
  
+static ssize_t rtpm_active_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	int ret;
+	spin_lock_irq(&dev->power.lock);
+	update_pm_runtime_accounting(dev);
+	ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
+	spin_unlock_irq(&dev->power.lock);
+	return ret;
+}
+
+static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);
+
+static ssize_t rtpm_suspended_time_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	int ret;
+	spin_lock_irq(&dev->power.lock);
+	update_pm_runtime_accounting(dev);
+	ret = sprintf(buf, "%i\n",
+		jiffies_to_msecs(dev->power.suspended_jiffies));
+	spin_unlock_irq(&dev->power.lock);
+	return ret;
+}
+
+static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);
+
 static ssize_t rtpm_status_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
@@ -254,6 +282,8 @@
 #ifdef CONFIG_PM_RUNTIME
 	&dev_attr_control.attr,
 	&dev_attr_runtime_status.attr,
+	&dev_attr_runtime_suspended_time.attr,
+	&dev_attr_runtime_active_time.attr,
 #endif
 	&dev_attr_wakeup.attr,
 #ifdef CONFIG_PM_SLEEP
@@ -477,8 +477,14 @@
 	enum rpm_request	request;
 	enum rpm_status		runtime_status;
 	int			runtime_error;
+	unsigned long		active_jiffies;
+	unsigned long		suspended_jiffies;
+	unsigned long		accounting_timestamp;
 #endif
 };
+
+extern void update_pm_runtime_accounting(struct device *dev);
+
  
 /*
  * The PM_EVENT_ messages are also used by drivers implementing the legacy
...	...	@@ -123,7 +123,46 @@
123	123	}
124	124	EXPORT_SYMBOL_GPL(pm_runtime_idle);
125	125
	126	+
126	127	/**
	128	+ * update_pm_runtime_accounting - Update the time accounting of power states
	129	+ * @dev: Device to update the accounting for
	130	+ *
	131	+ * In order to be able to have time accounting of the various power states
	132	+ * (as used by programs such as PowerTOP to show the effectiveness of runtime
	133	+ * PM), we need to track the time spent in each state.
	134	+ * update_pm_runtime_accounting must be called each time before the
	135	+ * runtime_status field is updated, to account the time in the old state
	136	+ * correctly.
	137	+ */
	138	+void update_pm_runtime_accounting(struct device *dev)
	139	+{
	140	+ unsigned long now = jiffies;
	141	+ int delta;
	142	+
	143	+ delta = now - dev->power.accounting_timestamp;
	144	+
	145	+ if (delta < 0)
	146	+ delta = 0;
	147	+
	148	+ dev->power.accounting_timestamp = now;
	149	+
	150	+ if (dev->power.disable_depth > 0)
	151	+ return;
	152	+
	153	+ if (dev->power.runtime_status == RPM_SUSPENDED)
	154	+ dev->power.suspended_jiffies += delta;
	155	+ else
	156	+ dev->power.active_jiffies += delta;
	157	+}
	158	+
	159	+static void __update_runtime_status(struct device *dev, enum rpm_status status)
	160	+{
	161	+ update_pm_runtime_accounting(dev);
	162	+ dev->power.runtime_status = status;
	163	+}
	164	+
	165	+/**
127	166	* __pm_runtime_suspend - Carry out run-time suspend of given device.
128	167	* @dev: Device to suspend.
129	168	* @from_wq: If set, the function has been called via pm_wq.
...	...	@@ -197,7 +236,7 @@
197	236	goto repeat;
198	237	}
199	238
200		- dev->power.runtime_status = RPM_SUSPENDING;
	239	+ __update_runtime_status(dev, RPM_SUSPENDING);
201	240	dev->power.deferred_resume = false;
202	241
203	242	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
...	...	@@ -228,7 +267,7 @@
228	267	}
229	268
230	269	if (retval) {
231		- dev->power.runtime_status = RPM_ACTIVE;
	270	+ __update_runtime_status(dev, RPM_ACTIVE);
232	271	if (retval == -EAGAIN \|\| retval == -EBUSY) {
233	272	if (dev->power.timer_expires == 0)
234	273	notify = true;
...	...	@@ -237,7 +276,7 @@
237	276	pm_runtime_cancel_pending(dev);
238	277	}
239	278	} else {
240		- dev->power.runtime_status = RPM_SUSPENDED;
	279	+ __update_runtime_status(dev, RPM_SUSPENDED);
241	280	pm_runtime_deactivate_timer(dev);
242	281
243	282	if (dev->parent) {
...	...	@@ -381,7 +420,7 @@
381	420	goto repeat;
382	421	}
383	422
384		- dev->power.runtime_status = RPM_RESUMING;
	423	+ __update_runtime_status(dev, RPM_RESUMING);
385	424
386	425	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) {
387	426	spin_unlock_irq(&dev->power.lock);
388	427
...	...	@@ -411,10 +450,10 @@
411	450	}
412	451
413	452	if (retval) {
414		- dev->power.runtime_status = RPM_SUSPENDED;
	453	+ __update_runtime_status(dev, RPM_SUSPENDED);
415	454	pm_runtime_cancel_pending(dev);
416	455	} else {
417		- dev->power.runtime_status = RPM_ACTIVE;
	456	+ __update_runtime_status(dev, RPM_ACTIVE);
418	457	if (parent)
419	458	atomic_inc(&parent->power.child_count);
420	459	}
...	...	@@ -848,7 +887,7 @@
848	887	}
849	888
850	889	out_set:
851		- dev->power.runtime_status = status;
	890	+ __update_runtime_status(dev, status);
852	891	dev->power.runtime_error = 0;
853	892	out:
854	893	spin_unlock_irqrestore(&dev->power.lock, flags);
...	...	@@ -1077,6 +1116,7 @@
1077	1116	dev->power.request_pending = false;
1078	1117	dev->power.request = RPM_REQ_NONE;
1079	1118	dev->power.deferred_resume = false;
	1119	+ dev->power.accounting_timestamp = jiffies;
1080	1120	INIT_WORK(&dev->power.work, pm_runtime_work);
1081	1121
1082	1122	dev->power.timer_expires = 0;
...	...	@@ -6,6 +6,7 @@
6	6	#include <linux/string.h>
7	7	#include <linux/pm_runtime.h>
8	8	#include <asm/atomic.h>
	9	+#include <linux/jiffies.h>
9	10	#include "power.h"
10	11
11	12	/*
...	...	@@ -111,6 +112,33 @@
111	112
112	113	static DEVICE_ATTR(control, 0644, control_show, control_store);
113	114
	115	+static ssize_t rtpm_active_time_show(struct device *dev,
	116	+ struct device_attribute attr, char buf)
	117	+{
	118	+ int ret;
	119	+ spin_lock_irq(&dev->power.lock);
	120	+ update_pm_runtime_accounting(dev);
	121	+ ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
	122	+ spin_unlock_irq(&dev->power.lock);
	123	+ return ret;
	124	+}
	125	+
	126	+static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);
	127	+
	128	+static ssize_t rtpm_suspended_time_show(struct device *dev,
	129	+ struct device_attribute attr, char buf)
	130	+{
	131	+ int ret;
	132	+ spin_lock_irq(&dev->power.lock);
	133	+ update_pm_runtime_accounting(dev);
	134	+ ret = sprintf(buf, "%i\n",
	135	+ jiffies_to_msecs(dev->power.suspended_jiffies));
	136	+ spin_unlock_irq(&dev->power.lock);
	137	+ return ret;
	138	+}
	139	+
	140	+static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);
	141	+
114	142	static ssize_t rtpm_status_show(struct device *dev,
115	143	struct device_attribute attr, char buf)
116	144	{
...	...	@@ -254,6 +282,8 @@
254	282	#ifdef CONFIG_PM_RUNTIME
255	283	&dev_attr_control.attr,
256	284	&dev_attr_runtime_status.attr,
	285	+ &dev_attr_runtime_suspended_time.attr,
	286	+ &dev_attr_runtime_active_time.attr,
257	287	#endif
258	288	&dev_attr_wakeup.attr,
259	289	#ifdef CONFIG_PM_SLEEP
...	...	@@ -477,8 +477,14 @@
477	477	enum rpm_request request;
478	478	enum rpm_status runtime_status;
479	479	int runtime_error;
	480	+ unsigned long active_jiffies;
	481	+ unsigned long suspended_jiffies;
	482	+ unsigned long accounting_timestamp;
480	483	#endif
481	484	};
	485	+
	486	+extern void update_pm_runtime_accounting(struct device *dev);
	487	+
482	488
483	489	/*
484	490	* The PM_EVENT_ messages are also used by drivers implementing the legacy