linux-kernel - Re: [RFC PATCH 3/3] thermal: trace: Trace when temperature is above a trip point

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Date:	Fri, 20 Jun 2014 18:24:42 +0100
From:	"Javi Merino" <javi.merino@....com>
To:	Punit Agrawal <punit.agrawal@....com>
Cc:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <edubezval@...il.com>
Subject: Re: [RFC PATCH 3/3] thermal: trace: Trace when temperature is above
 a trip point

Hi Punit,

On Wed, Jun 11, 2014 at 12:31:44PM +0100, Punit Agrawal wrote:
> Create a new event to trace when the temperature is above a trip
> point. Use the trace-point when handling non-critical and critical
> trip pionts.
> 
> Cc: Zhang Rui <rui.zhang@...el.com>
> Cc: Eduardo Valentin <edubezval@...il.com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Signed-off-by: Punit Agrawal <punit.agrawal@....com>
> ---
> Hi Steven,
> 
> I am facing an issue with partial trace being emitted when using
> __print_symbolic in this patch. 
> 
> When the trip_type is THERMAL_TRIP_ACTIVE (i.e., the first value in
> the symbol map), the emitted trace contains the corresponding string
> ("active"). But for other values of trip_type an empty string is
> emitted in the trace.
> 
> I've looked at other uses of __print_symbolic in the kernel and don't
> see any difference in usage. Do you know what could be causing this or
> alternately have any pointers on how to debug this behaviour?
> 
> Thanks.
> Punit
> 
>  drivers/thermal/fair_share.c   |    7 ++++++-
>  drivers/thermal/step_wise.c    |    5 ++++-
>  drivers/thermal/thermal_core.c |    2 ++
>  include/trace/events/thermal.h |   30 ++++++++++++++++++++++++++++++
>  4 files changed, 42 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
> index 944ba2f..2cddd68 100644
> --- a/drivers/thermal/fair_share.c
> +++ b/drivers/thermal/fair_share.c
> @@ -23,6 +23,7 @@
>   */
>  
>  #include <linux/thermal.h>
> +#include <trace/events/thermal.h>
>  
>  #include "thermal_core.h"
>  
> @@ -34,14 +35,18 @@ static int get_trip_level(struct thermal_zone_device *tz)
>  {
>  	int count = 0;
>  	unsigned long trip_temp;
> +	enum thermal_trip_type trip_type;
>  
>  	if (tz->trips == 0 || !tz->ops->get_trip_temp)
>  		return 0;
>  
>  	for (count = 0; count < tz->trips; count++) {
>  		tz->ops->get_trip_temp(tz, count, &trip_temp);
> -		if (tz->temperature < trip_temp)
> +		if (tz->temperature < trip_temp) {
> +			tz->ops->get_trip_type(tz, count, &trip_type);
> +			trace_thermal_zone_trip(tz, count, trip_type);

This should be outside the if condition.  You want to report when trip
points have been hit, like in the step_wise code below.

>  			break;
> +		}
>  	}
>  	return count;
>  }
> diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
> index f251521..3b54c2c 100644
> --- a/drivers/thermal/step_wise.c
> +++ b/drivers/thermal/step_wise.c
> @@ -23,6 +23,7 @@
>   */
>  
>  #include <linux/thermal.h>
> +#include <trace/events/thermal.h>
>  
>  #include "thermal_core.h"
>  
> @@ -129,8 +130,10 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
>  
>  	trend = get_tz_trend(tz, trip);
>  
> -	if (tz->temperature >= trip_temp)
> +	if (tz->temperature >= trip_temp) {
>  		throttle = true;
> +		trace_thermal_zone_trip(tz, trip, trip_type);
> +	}
>  
>  	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
>  				trip, trip_type, trip_temp, trend, throttle);
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index c74c78d..454884a 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -371,6 +371,8 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
>  	if (tz->temperature < trip_temp)
>  		return;
>  
> +	trace_thermal_zone_trip(tz, trip, trip_type);
> +
>  	if (tz->ops->notify)
>  		tz->ops->notify(tz, trip, trip_type);
>  

Cheers,
Javi

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