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SubjectRe: [PATCH 2/2] drivers: devfreq: add tracing for scheduling work
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Hi Steven,

On 2/14/19 8:07 PM, Steven Rostedt wrote:
> On Thu, 14 Feb 2019 19:57:56 +0100
> Lukasz Luba <l.luba@partner.samsung.com> wrote:
>
>> This patch add basic tracing of the devfreq workqueue and delayed work.
>> It aims to capture changes of the polling intervals and device state.
>>
>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>> Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
>> ---
>> drivers/devfreq/devfreq.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index 0ae3de7..c9714fd 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -29,6 +29,9 @@
>> #include <linux/of.h>
>> #include "governor.h"
>>
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/devfreq.h>
>> +
>> static struct class *devfreq_class;
>>
>> /*
>> @@ -394,6 +397,11 @@ static void devfreq_monitor(struct work_struct *work)
>> queue_delayed_work(devfreq_wq, &devfreq->work,
>> msecs_to_jiffies(devfreq->profile->polling_ms));
>> mutex_unlock(&devfreq->lock);
>> +
>> + trace_devfreq_monitor(dev_name(&devfreq->dev), devfreq->previous_freq,
>> + devfreq->profile->polling_ms,
>> + devfreq->last_status.busy_time,
>> + devfreq->last_status.total_time);
>
> I would pass just devfreq into the tracepoint (it will be less work by
> gcc in this code path), and do all this work in the TP__fast_assign()
>
> The string can still handle this with:
>
> __string(dev_name, dev_name(&devfreq->dev))
>
> And assigned:
>
> __assign_str(dev_name, dev_name(&devfreq->dev))
>
> But the rest of fast assign should be:
>
> TP_fast_assign(
> __entry->freq = devfreq->previous_freq;
> __entry->busy_time = devfreq->last_status.busy_time;
> __entry->total_time = devfreq->last_status.total_time;
> __entry->polling_ms = devfreq->profile->polling_ms;
> __assign_str(dev_name, dev_name(&deqfreq->dev));
> }
I agree, it makes sense. Let me test this approach and then send v3
patches. Thank you for the review.

Regards,
Lukasz
>
> -- Steve
>
>> }
>>
>> /**
>
>
>

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