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 <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>
mgowda · Jul 19, 2010 · 8d4b9d1 · 8d4b9d1
1 parent 0fcb4ee
commit 8d4b9d1
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Showing 3 changed files with 83 additions and 7 deletions.
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
@@ -123,6 +123,45 @@ int pm_runtime_idle(struct device *dev)
 }
 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.
@@ -197,7 +236,7 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
 		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 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
 	}
 
 	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 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
 			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 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
 		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 @@ int __pm_runtime_resume(struct device *dev, bool from_wq)
 	}
 
 	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 @@ int __pm_runtime_set_status(struct device *dev, unsigned int status)
 	}
 
  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 @@ void pm_runtime_init(struct device *dev)
 	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;

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
@@ -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 ssize_t control_store(struct device * dev, struct device_attribute *attr,
 
 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 @@ static struct attribute * power_attrs[] = {
 #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

diff --git a/include/linux/pm.h b/include/linux/pm.h
@@ -477,9 +477,15 @@ struct dev_pm_info {
 	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
  * suspend framework, based on the ->suspend() and ->resume() callbacks common