Commit 015abee4 authored by Vilas Bhat's avatar Vilas Bhat Committed by Rafael J. Wysocki
Browse files

PM: runtime: add tracepoint for runtime_status changes 



Existing runtime PM ftrace events (`rpm_suspend`, `rpm_resume`,
`rpm_return_int`) offer limited visibility into the exact timing of device
runtime power state transitions, particularly when asynchronous operations
are involved. When the `rpm_suspend` or `rpm_resume` functions are invoked
with the `RPM_ASYNC` flag, a return value of 0 i.e., success merely
indicates that the device power state request has been queued, not that
the device has yet transitioned.

A new ftrace event, `rpm_status`, is introduced. This event directly logs
the `power.runtime_status` value of a device whenever it changes providing
granular tracking of runtime power state transitions regardless of
synchronous or asynchronous `rpm_suspend` / `rpm_resume` usage.

Signed-off-by: default avatarVilas Bhat <vilasbhat@google.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent b7d46644

drivers/base/power/runtime.c

+1 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ static void update_pm_runtime_accounting(struct device *dev) 
static void __update_runtime_status(struct device *dev, enum rpm_status status)

{

	update_pm_runtime_accounting(dev);

	trace_rpm_status(dev, status);

	dev->power.runtime_status = status;

}

include/trace/events/rpm.h

+42 −0
Original line number Diff line number Diff line
@@ -101,6 +101,48 @@ TRACE_EVENT(rpm_return_int, 
		__entry->ret)

);



#define RPM_STATUS_STRINGS \

	EM(RPM_INVALID, "RPM_INVALID") \

	EM(RPM_ACTIVE, "RPM_ACTIVE") \

	EM(RPM_RESUMING, "RPM_RESUMING") \

	EM(RPM_SUSPENDED, "RPM_SUSPENDED") \

	EMe(RPM_SUSPENDING, "RPM_SUSPENDING")



/* Enums require being exported to userspace, for user tool parsing. */

#undef EM

#undef EMe

#define EM(a, b)	TRACE_DEFINE_ENUM(a);

#define EMe(a, b)	TRACE_DEFINE_ENUM(a);



RPM_STATUS_STRINGS



/*

 * Now redefine the EM() and EMe() macros to map the enums to the strings that

 * will be printed in the output.

 */

#undef EM

#undef EMe

#define EM(a, b)	{ a, b },

#define EMe(a, b)	{ a, b }



TRACE_EVENT(rpm_status,

	TP_PROTO(struct device *dev, enum rpm_status status),

	TP_ARGS(dev, status),



	TP_STRUCT__entry(

		__string(name,	dev_name(dev))

		__field(int,	status)

	),



	TP_fast_assign(

		__assign_str(name, dev_name(dev));

		__entry->status = status;

	),



	TP_printk("%s status=%s", __get_str(name),

		__print_symbolic(__entry->status, RPM_STATUS_STRINGS))

);



#endif /* _TRACE_RUNTIME_POWER_H */



/* This part must be outside protection */