Messages in this thread | | | Date | Fri, 18 Sep 2015 14:55:51 +0100 | From | Javi Merino <> | Subject | Re: [PATCH v6 4/5] devfreq_cooling: add trace information |
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Hi Steve,
On Thu, Sep 10, 2015 at 06:19:28PM +0100, Steven Rostedt wrote: > On Thu, 10 Sep 2015 18:09:31 +0100 > Javi Merino <javi.merino@arm.com> wrote: > > > Tracing is useful for debugging and performance tuning. Add similar > > traces to what's present in the cpu cooling device. > > > > Cc: Zhang Rui <rui.zhang@intel.com> > > Cc: Eduardo Valentin <edubezval@gmail.com> > > Cc: Steven Rostedt <rostedt@goodmis.org> > > Cc: Ingo Molnar <mingo@redhat.com> > > Signed-off-by: Javi Merino <javi.merino@arm.com> > > --- > > drivers/thermal/devfreq_cooling.c | 6 +++++ > > include/trace/events/thermal.h | 53 +++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 59 insertions(+) > > > > diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c > > index a032c5d5c374..a27206815066 100644 > > --- a/drivers/thermal/devfreq_cooling.c > > +++ b/drivers/thermal/devfreq_cooling.c > > @@ -25,6 +25,8 @@ > > #include <linux/pm_opp.h> > > #include <linux/thermal.h> > > > > +#include <trace/events/thermal.h> > > + > > static DEFINE_MUTEX(devfreq_lock); > > static DEFINE_IDR(devfreq_idr); > > > > @@ -293,6 +295,9 @@ static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cd > > /* Get static power */ > > static_power = get_static_power(dfc, freq); > > > > + trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, > > + static_power); > > + > > *power = dyn_power + static_power; > > > > return 0; > > @@ -348,6 +353,7 @@ static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, > > break; > > > > *state = i; > > + trace_thermal_power_devfreq_limit(cdev, freq, *state, power); > > I'm curious, does changing the above to: > > trace_thermal_power_devfreq_limit(cdev, freq, i, power); > > make the compiled code better? > > A tracepoint does some whacky things, and gcc may not optimize this.
I've compared the generated assembly on arm, arm64 and x86_64 and both options generate exactly the same code.
Cheers, Javi
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