Hello Jean, On Wed, Jan 05, 2011 at 07:49:02PM +0100, ext jean.pihet@xxxxxxxxxxxxxx wrote: > From: Jean Pihet <j-pihet@xxxxxx> > > Provides documentation for the following: > - the new power trace API, > - the old (legacy) power trace API, > - the DEPRECATED Kconfig option usage. > > Signed-off-by: Jean Pihet <j-pihet@xxxxxx> > --- > Documentation/trace/events-power.txt | 90 ++++++++++++++++++++++++++++++++++ > 1 files changed, 90 insertions(+), 0 deletions(-) > create mode 100644 Documentation/trace/events-power.txt > > diff --git a/Documentation/trace/events-power.txt b/Documentation/trace/events-power.txt > new file mode 100644 > index 0000000..96d87b6 > --- /dev/null > +++ b/Documentation/trace/events-power.txt > @@ -0,0 +1,90 @@ > + > + Subsystem Trace Points: power > + > +The power tracing system captures events related to power transitions > +within the kernel. Broadly speaking there are three major subheadings: > + > + o Power state switch which reports events related to suspend (S-states), > + cpuidle (C-states) and cpufreq (P-states) > + o System clock related changes What do you mean by system clock here? I see that you are covering cpu rate changes and system clock (?) here. How about memory clock changes? Would it make sense to have a major subheading for it? Maybe you are targeting it be traced by means of clocks event (item 2. bellow).. > + o Power domains related changes and transitions > + > +This document describes what each of the tracepoints is and why they > +might be useful. > + > +Cf. include/trace/events/power.h for the events definitions. > + > +1. Power state switch events > +============================ > + > +1.1 New trace API > +----------------- > + > +A 'cpu' event class gathers the CPU-related events: cpuidle and > +cpufreq. > + > +cpu_idle "state=%lu cpu_id=%lu" > +cpu_frequency "state=%lu cpu_id=%lu" > + > +A suspend event is used to indicate the system going in and out of the > +suspend mode: > + > +machine_suspend "state=%lu" > + > + > +Note: the value of '-1' or '4294967295' for state means an exit from the current state, > +i.e. trace_cpu_idle(4, smp_processor_id()) means that the system > +enters the idle state 4, while trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()) > +means that the system exits the previous idle state. > + > +The event which has 'state=4294967295' in the trace is very important to the user > +space tools which are using it to detect the end of the current state, and so to > +correctly draw the states diagrams and to calculate accurate statistics etc. > + > +1.2 DEPRECATED trace API > +------------------------ > + > +A new Kconfig option CONFIG_EVENT_POWER_TRACING_DEPRECATED with the default value of > +'y' has been created. This allows the legacy trace power API to be used conjointly > +with the new trace API. > +The Kconfig option, the old trace API (in include/trace/events/power.h) and the > +old trace points will disappear in a future release (namely 2.6.41). > + > +power_start "type=%lu state=%lu cpu_id=%lu" > +power_frequency "type=%lu state=%lu cpu_id=%lu" > +power_end "cpu_id=%lu" > + > +The 'type' parameter takes one of those macros: > + . POWER_NONE = 0, > + . POWER_CSTATE = 1, /* C-State */ > + . POWER_PSTATE = 2, /* Fequency change or DVFS */ > + > +The 'state' parameter is set depending on the type: > + . Target C-state for type=POWER_CSTATE, > + . Target frequency for type=POWER_PSTATE, > + > +power_end is used to indicate the exit of a state, corresponding to the latest > +power_start event. > + > +2. Clocks events > +================ > +The clock events are used for clock enable/disable and for > +clock rate change. > + > +clock_enable "%s state=%lu cpu_id=%lu" > +clock_disable "%s state=%lu cpu_id=%lu" > +clock_set_rate "%s state=%lu cpu_id=%lu" > + > +The first parameter gives the clock name (e.g. "gpio1_iclk"). > +The second parameter is '1' for enable, '0' for disable, the target > +clock rate for set_rate. > + > +3. Power domains events > +======================= > +The power domain events are used for power domains transitions > + > +power_domain_target "%s state=%lu cpu_id=%lu" > + > +The first parameter gives the power domain name (e.g. "mpu_pwrdm"). > +The second parameter is the power domain target state. > + > -- > 1.7.2.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Eduardo Valentin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
