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SubjectRe: [PATCH v3 2/3] devfreq: add clearing transitions stats
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On 12/5/19 11:55 PM, Kamil Konieczny wrote:
> Add clearing transition table and time in states devfreq statistics
> by writing 0 (zero) to trans_stat file in devfreq sysfs. An example use
> is like following:
>
> echo 0 > /sys/class/devfreq/devfreqX/trans_stat
>
> Signed-off-by: Kamil Konieczny <k.konieczny@samsung.com>
> ---
> Changes in v3:
> - add checks for zero in input and clear stats only when zero is written
> to trans_stats
> - change documentation of trans_stat in sysfs
>
> Changes in v2:
> - instead of creating new sysfs file, add new functionality to trans_stat
> and clear stats when anything is writen to it
> ---
> Documentation/ABI/testing/sysfs-class-devfreq | 11 +++++---
> drivers/devfreq/devfreq.c | 27 ++++++++++++++++++-
> 2 files changed, 33 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
> index 75897e2fde43..9758eb85ade3 100644
> --- a/Documentation/ABI/testing/sysfs-class-devfreq
> +++ b/Documentation/ABI/testing/sysfs-class-devfreq
> @@ -55,12 +55,15 @@ What: /sys/class/devfreq/.../trans_stat
> Date: October 2012
> Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
> Description:
> - This ABI shows the statistics of devfreq behavior on a
> - specific device. It shows the time spent in each state and
> - the number of transitions between states.
> + This ABI shows or clears the statistics of devfreq behavior
> + on a specific device. It shows the time spent in each state
> + and the number of transitions between states.
> In order to activate this ABI, the devfreq target device
> driver should provide the list of available frequencies
> - with its profile.
> + with its profile. If need to reset the statistics of devfreq
> + behavior on a specific device, enter 0(zero) to 'trans_stat'
> + as following:
> + echo 0 > /sys/class/devfreq/.../trans_stat
>
> What: /sys/class/devfreq/.../userspace/set_freq
> Date: September 2011
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index abecadeb3dc2..218eb64d7f28 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -1478,7 +1478,32 @@ static ssize_t trans_stat_show(struct device *dev,
> devfreq->total_trans);
> return len;
> }
> -static DEVICE_ATTR_RO(trans_stat);
> +
> +static ssize_t trans_stat_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct devfreq *df = to_devfreq(dev);
> + unsigned int cnt = df->profile->max_state;
> + int err, value;
> +
> + if (cnt == 0)
> + return count;
> +
> + err = kstrtoint(buf, 10, &value);
> + if (err || value != 0)
> + return count;

Better returning -EINVAL to inform the error of user.
I changed it by myself.

> +
> + mutex_lock(&df->lock);
> + memset(df->time_in_state, 0, cnt * sizeof(u64));

Changed the size calculation way as following by myself:

memset(df->time_in_state, 0, (df->profile->max_state *
sizeof(*devfreq->time_in_state)));

> + memset(df->trans_table, 0, cnt * cnt * sizeof(int));

Changed the size calculation way with array3_size() as following by myself:
memset(df->trans_table, 0, array3_size(sizeof(unsigned int),
df->profile->max_state,
df->profile->max_state));


> + df->last_stat_updated = get_jiffies_64();
> + df->total_trans = 0;

Changed the init sequence as following by myself.
df->total_trans = 0;
df->last_stat_updated = get_jiffies_64();

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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