Hi,
this patch series tries to improve devfreq statistics:
- do conversion to use 64-bit jiffies for storing elapsed time and prevent
counters overflow,
- add ability to reset statistics using sysfs,
- move statistics data to separate structure for improved code
readability and maintenance.
Changes in v2:
- added Acked-by to first patch
- dropped spinlock patch, there is mutex used for protecting stats data
- rewrite clearing statistics, suggested by Chanwoo Choi: reuse
trans_stats sysfs file, any write to it will clear devfreq stats
- dropped change var name last_stat_updated
- squashed three last patches into one, as it turned out that freq_table
from devfreq_profile is used by other drivers
- rebased on linux-next
Kamil Konieczny (3):
devfreq: change time stats to 64-bit
devfreq: add clearing transitions stats
devfreq: move statistics to separate struct
drivers/devfreq/devfreq.c | 86 +++++++++++++++++++++++++++------------
include/linux/devfreq.h | 31 ++++++++++----
2 files changed, 81 insertions(+), 36 deletions(-)
--
2.24.0
Change time stats counting to bigger type by using 64-bit jiffies.
This will make devfreq stats code look similar to cpufreq stats and
prevents overflow (for HZ = 1000 after 49.7 days).
Signed-off-by: Kamil Konieczny <[email protected]>
Acked-by: Chanwoo Choi <[email protected]>
---
Changes in v2:
added Acked-by, rebased on linux-next
drivers/devfreq/devfreq.c | 14 +++++++-------
include/linux/devfreq.h | 4 ++--
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index bdeb4189c978..0e2030403e4a 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -199,10 +199,10 @@ static int set_freq_table(struct devfreq *devfreq)
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
{
int lev, prev_lev, ret = 0;
- unsigned long cur_time;
+ unsigned long long cur_time;
lockdep_assert_held(&devfreq->lock);
- cur_time = jiffies;
+ cur_time = get_jiffies_64();
/* Immediately exit if previous_freq is not initialized yet. */
if (!devfreq->previous_freq)
@@ -525,7 +525,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
msecs_to_jiffies(devfreq->profile->polling_ms));
out_update:
- devfreq->last_stat_updated = jiffies;
+ devfreq->last_stat_updated = get_jiffies_64();
devfreq->stop_polling = false;
if (devfreq->profile->get_cur_freq &&
@@ -748,7 +748,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
devfreq->profile->max_state,
- sizeof(unsigned long),
+ sizeof(*devfreq->time_in_state),
GFP_KERNEL);
if (!devfreq->time_in_state) {
mutex_unlock(&devfreq->lock);
@@ -756,7 +756,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
goto err_devfreq;
}
- devfreq->last_stat_updated = jiffies;
+ devfreq->last_stat_updated = get_jiffies_64();
srcu_init_notifier_head(&devfreq->transition_notifier_list);
@@ -1470,8 +1470,8 @@ static ssize_t trans_stat_show(struct device *dev,
for (j = 0; j < max_state; j++)
len += sprintf(buf + len, "%10u",
devfreq->trans_table[(i * max_state) + j]);
- len += sprintf(buf + len, "%10u\n",
- jiffies_to_msecs(devfreq->time_in_state[i]));
+ len += sprintf(buf + len, "%10llu\n", (u64)
+ jiffies64_to_msecs(devfreq->time_in_state[i]));
}
len += sprintf(buf + len, "Total transition : %u\n",
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2bae9ed3c783..b81a86e47fb9 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -174,8 +174,8 @@ struct devfreq {
/* information for device frequency transition */
unsigned int total_trans;
unsigned int *trans_table;
- unsigned long *time_in_state;
- unsigned long last_stat_updated;
+ u64 *time_in_state;
+ unsigned long long last_stat_updated;
struct srcu_notifier_head transition_notifier_list;
};
--
2.24.0
On 12/5/19 12:00 AM, Kamil Konieczny wrote:
> Change time stats counting to bigger type by using 64-bit jiffies.
> This will make devfreq stats code look similar to cpufreq stats and
> prevents overflow (for HZ = 1000 after 49.7 days).
>
> Signed-off-by: Kamil Konieczny <[email protected]>
> Acked-by: Chanwoo Choi <[email protected]>
> ---
> Changes in v2:
> added Acked-by, rebased on linux-next
>
> drivers/devfreq/devfreq.c | 14 +++++++-------
> include/linux/devfreq.h | 4 ++--
> 2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index bdeb4189c978..0e2030403e4a 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -199,10 +199,10 @@ static int set_freq_table(struct devfreq *devfreq)
> int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
> {
> int lev, prev_lev, ret = 0;
> - unsigned long cur_time;
> + unsigned long long cur_time;
It looks better to use 'u64' instead of 'unsigned long long'.
Because get_jiffies_u64 has 'u64' return type.
>
> lockdep_assert_held(&devfreq->lock);
> - cur_time = jiffies;
> + cur_time = get_jiffies_64();
>
> /* Immediately exit if previous_freq is not initialized yet. */
> if (!devfreq->previous_freq)
> @@ -525,7 +525,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
> msecs_to_jiffies(devfreq->profile->polling_ms));
>
> out_update:
> - devfreq->last_stat_updated = jiffies;
> + devfreq->last_stat_updated = get_jiffies_64();
> devfreq->stop_polling = false;
>
> if (devfreq->profile->get_cur_freq &&
> @@ -748,7 +748,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>
> devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
> devfreq->profile->max_state,
> - sizeof(unsigned long),
> + sizeof(*devfreq->time_in_state),
> GFP_KERNEL);
> if (!devfreq->time_in_state) {
> mutex_unlock(&devfreq->lock);
> @@ -756,7 +756,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
> goto err_devfreq;
> }
>
> - devfreq->last_stat_updated = jiffies;
> + devfreq->last_stat_updated = get_jiffies_64();
>
> srcu_init_notifier_head(&devfreq->transition_notifier_list);
>
> @@ -1470,8 +1470,8 @@ static ssize_t trans_stat_show(struct device *dev,
> for (j = 0; j < max_state; j++)
> len += sprintf(buf + len, "%10u",
> devfreq->trans_table[(i * max_state) + j]);
> - len += sprintf(buf + len, "%10u\n",
> - jiffies_to_msecs(devfreq->time_in_state[i]));
> + len += sprintf(buf + len, "%10llu\n", (u64)
> + jiffies64_to_msecs(devfreq->time_in_state[i]));
> }
>
> len += sprintf(buf + len, "Total transition : %u\n",
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 2bae9ed3c783..b81a86e47fb9 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -174,8 +174,8 @@ struct devfreq {
> /* information for device frequency transition */
> unsigned int total_trans;
> unsigned int *trans_table;
> - unsigned long *time_in_state;
> - unsigned long last_stat_updated;
> + u64 *time_in_state;
> + unsigned long long last_stat_updated;
ditto. 'unsigned long long' -> 'u64'.
>
> struct srcu_notifier_head transition_notifier_list;
> };
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
Hi,
On 05.12.2019 01:27, Chanwoo Choi wrote:
> On 12/5/19 12:00 AM, Kamil Konieczny wrote:
>> Change time stats counting to bigger type by using 64-bit jiffies.
>> This will make devfreq stats code look similar to cpufreq stats and
>> prevents overflow (for HZ = 1000 after 49.7 days).
>>
>> Signed-off-by: Kamil Konieczny <[email protected]>
>> Acked-by: Chanwoo Choi <[email protected]>
>> ---
>> Changes in v2:
>> added Acked-by, rebased on linux-next
>>
>> drivers/devfreq/devfreq.c | 14 +++++++-------
>> include/linux/devfreq.h | 4 ++--
>> 2 files changed, 9 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
>> index bdeb4189c978..0e2030403e4a 100644
>> --- a/drivers/devfreq/devfreq.c
>> +++ b/drivers/devfreq/devfreq.c
>> @@ -199,10 +199,10 @@ static int set_freq_table(struct devfreq *devfreq)
>> int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
>> {
>> int lev, prev_lev, ret = 0;
>> - unsigned long cur_time;
>> + unsigned long long cur_time;
>
> It looks better to use 'u64' instead of 'unsigned long long'.
> Because get_jiffies_u64 has 'u64' return type.
You are right, I will change this and send v3.
>>
>> lockdep_assert_held(&devfreq->lock);
>> - cur_time = jiffies;
>> + cur_time = get_jiffies_64();
>>
>> /* Immediately exit if previous_freq is not initialized yet. */
>> if (!devfreq->previous_freq)
>> @@ -525,7 +525,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
>> msecs_to_jiffies(devfreq->profile->polling_ms));
>>
>> out_update:
>> - devfreq->last_stat_updated = jiffies;
>> + devfreq->last_stat_updated = get_jiffies_64();
>> devfreq->stop_polling = false;
>>
>> if (devfreq->profile->get_cur_freq &&
>> @@ -748,7 +748,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>>
>> devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
>> devfreq->profile->max_state,
>> - sizeof(unsigned long),
>> + sizeof(*devfreq->time_in_state),
>> GFP_KERNEL);
>> if (!devfreq->time_in_state) {
>> mutex_unlock(&devfreq->lock);
>> @@ -756,7 +756,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
>> goto err_devfreq;
>> }
>>
>> - devfreq->last_stat_updated = jiffies;
>> + devfreq->last_stat_updated = get_jiffies_64();
>>
>> srcu_init_notifier_head(&devfreq->transition_notifier_list);
>>
>> @@ -1470,8 +1470,8 @@ static ssize_t trans_stat_show(struct device *dev,
>> for (j = 0; j < max_state; j++)
>> len += sprintf(buf + len, "%10u",
>> devfreq->trans_table[(i * max_state) + j]);
>> - len += sprintf(buf + len, "%10u\n",
>> - jiffies_to_msecs(devfreq->time_in_state[i]));
>> + len += sprintf(buf + len, "%10llu\n", (u64)
>> + jiffies64_to_msecs(devfreq->time_in_state[i]));
>> }
>>
>> len += sprintf(buf + len, "Total transition : %u\n",
>> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
>> index 2bae9ed3c783..b81a86e47fb9 100644
>> --- a/include/linux/devfreq.h
>> +++ b/include/linux/devfreq.h
>> @@ -174,8 +174,8 @@ struct devfreq {
>> /* information for device frequency transition */
>> unsigned int total_trans;
>> unsigned int *trans_table;
>> - unsigned long *time_in_state;
>> - unsigned long last_stat_updated;
>> + u64 *time_in_state;
>> + unsigned long long last_stat_updated;
>
> ditto. 'unsigned long long' -> 'u64'.
Yes, will change this too.
>> struct srcu_notifier_head transition_notifier_list;
>> };
>>
--
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland