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

From: Punit Agrawal
Date: Tue Jun 24 2014 - 06:41:53 EST


"Javi Merino" <javi.merino@xxxxxxx> writes:

> 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@xxxxxxxxx>
>> Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
>> ---
>> 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.
>

It turned out to be a bit more subtle than moving the trace outside the
if. I have the below fixup with an added comment. Let me know if that
doesn't solve the problem.

-- >8 --
Subject: [PATCH] fixup! thermal: trace: Trace when temperature is above a
trip point

---
drivers/thermal/fair_share.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
index 2cddd68..6e0a3fb 100644
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -42,12 +42,19 @@ static int get_trip_level(struct thermal_zone_device *tz)

for (count = 0; count < tz->trips; count++) {
tz->ops->get_trip_temp(tz, count, &trip_temp);
- if (tz->temperature < trip_temp) {
- tz->ops->get_trip_type(tz, count, &trip_type);
- trace_thermal_zone_trip(tz, count, trip_type);
+ if (tz->temperature < trip_temp)
break;
- }
}
+
+ /*
+ * count > 0 only if temperature is greater than first trip
+ * point, in which case, trip_point = count - 1
+ */
+ if (count > 0) {
+ tz->ops->get_trip_type(tz, count - 1, &trip_type);
+ trace_thermal_zone_trip(tz, count - 1, trip_type);
+ }
+
return count;
}

--
1.7.10.4

>> 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
>
> --
> 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/
--
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/