linux-kernel - Re: [PATCH v3 7/7] drivers: devfreq: add tracing for scheduling work

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Date:   Thu, 14 Feb 2019 13:57:54 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Lukasz Luba <l.luba@...tner.samsung.com>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Cc:     b.zolnierkie@...sung.com, myungjoo.ham@...sung.com,
        kyungmin.park@...sung.com, m.szyprowski@...sung.com,
        s.nawrocki@...sung.com, joel@...lfernandes.org,
        chris.diamand@....com, mka@...omium.org, rostedt@...dmis.org,
        mingo@...hat.com
Subject: Re: [PATCH v3 7/7] drivers: devfreq: add tracing for scheduling
 work

Hi Lukasz,

On 19. 2. 13. 오전 7:23, Lukasz Luba 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.
> 
> Signed-off-by: Lukasz Luba <l.luba@...tner.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 29e99ce..c1d0d8c 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>
> +
>  /* The ~30% load threshold used for load calculation (due to fixed point
>   * arithmetic) */
>  #define LOAD_THRESHOLD_IN_DEVICE_USAGE (300)
> @@ -418,6 +421,7 @@ static void devfreq_monitor(struct work_struct *work)
>  	struct devfreq *devfreq = container_of(work,
>  					struct devfreq, work.work);
>  	unsigned int polling_ms;
> +	const char *df_name = dev_name(&devfreq->dev);

nit: You can use 'dev_name(&devfreq->dev)' directly
without defining the separate df_name.

>  
>  	mutex_lock(&devfreq->lock);
>  	polling_ms = devfreq_get_polling_delay(devfreq);
> @@ -429,6 +433,10 @@ static void devfreq_monitor(struct work_struct *work)
>  	schedule_delayed_work(&devfreq->work,
>  			      msecs_to_jiffies(polling_ms));
>  	mutex_unlock(&devfreq->lock);
> +
> +	trace_devfreq_monitor(df_name, devfreq->previous_freq, polling_ms,
> +			      devfreq->last_status.busy_time,
> +			      devfreq->last_status.total_time);

Regardless of type of work,
I think that trace point is necessary for devfreq framework.

Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>

>  }
>  
>  /**
> 

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics