@@ -810,6 +810,11 @@ unlock:
}
EXPORT_SYMBOL(devfreq_set_min);
+int devfreq_update_stats(struct devfreq *df)
+{
+ return df->profile->get_dev_status(df->dev.parent, &df->last_status);
+}
+
static ssize_t governor_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -21,17 +21,20 @@
static int devfreq_simple_ondemand_func(struct devfreq *df,
unsigned long *freq)
{
- struct devfreq_dev_status stat;
- int err = df->profile->get_dev_status(df->dev.parent, &stat);
+ int err;
+ struct devfreq_dev_status *stat;
unsigned long long a, b;
unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
struct devfreq_simple_ondemand_data *data = df->data;
unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
+ err = devfreq_update_stats(df);
if (err)
return err;
+ stat = &df->last_status;
+
if (data) {
if (data->upthreshold)
dfso_upthreshold = data->upthreshold;
@@ -43,41 +46,41 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
return -EINVAL;
/* Assume MAX if it is going to be divided by zero */
- if (stat.total_time == 0) {
+ if (stat->total_time == 0) {
*freq = max;
return 0;
}
/* Prevent overflow */
- if (stat.busy_time >= (1 << 24) || stat.total_time >= (1 << 24)) {
- stat.busy_time >>= 7;
- stat.total_time >>= 7;
+ if (stat->busy_time >= (1 << 24) || stat->total_time >= (1 << 24)) {
+ stat->busy_time >>= 7;
+ stat->total_time >>= 7;
}
/* Set MAX if it's busy enough */
- if (stat.busy_time * 100 >
- stat.total_time * dfso_upthreshold) {
+ if (stat->busy_time * 100 >
+ stat->total_time * dfso_upthreshold) {
*freq = max;
return 0;
}
/* Set MAX if we do not know the initial frequency */
- if (stat.current_frequency == 0) {
+ if (stat->current_frequency == 0) {
*freq = max;
return 0;
}
/* Keep the current frequency */
- if (stat.busy_time * 100 >
- stat.total_time * (dfso_upthreshold - dfso_downdifferential)) {
- *freq = stat.current_frequency;
+ if (stat->busy_time * 100 >
+ stat->total_time * (dfso_upthreshold - dfso_downdifferential)) {
+ *freq = stat->current_frequency;
return 0;
}
/* Set the desired frequency based on the load */
- a = stat.busy_time;
- a *= stat.current_frequency;
- b = div_u64(a, stat.total_time);
+ a = stat->busy_time;
+ a *= stat->current_frequency;
+ b = div_u64(a, stat->total_time);
b *= 100;
b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
*freq = (unsigned long) b;
@@ -161,6 +161,7 @@ struct devfreq {
struct delayed_work work;
unsigned long previous_freq;
+ struct devfreq_dev_status last_status;
void *data; /* private data for governors */
@@ -206,6 +207,7 @@ extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
int devfreq_set_min(struct devfreq *df, unsigned long value);
int devfreq_set_max(struct devfreq *df, unsigned long value);
+int devfreq_update_stats(struct devfreq *df);
#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
/**
@@ -302,6 +304,11 @@ static inline int devfreq_set_max(struct devfreq *df, unsigned long value)
{
return -EINVAL;
}
+
+static inline int devfreq_update_stats(struct devfreq *df)
+{
+ return -EINVAL;
+}
#endif /* CONFIG_PM_DEVFREQ */
#endif /* __LINUX_DEVFREQ_H__ */
The return value of get_dev_status() can be reused. Cache it so that other parts of the kernel can reuse it instead of having to call the same function again. Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Javi Merino <javi.merino@arm.com> --- This patch tries to let multiple components. To summarize the discussion in v1[1] I can think of three alternatives: 1) Change get_dev_status() to return absolute values for busy_time and total_time 2) Make core devfreq call get_dev_status() periodically (for example, before calling the governor) and all the entities that want access can do so via a pointer in devfreq 3) Make the simple ondemand governor call get_dev_status() periodically and cache it, forcing all the other entities to rely on that governor being active [1] http://thread.gmane.org/gmane.linux.power-management.general/61936/focus=61993 This patch implements option 3) drivers/devfreq/devfreq.c | 5 +++++ drivers/devfreq/governor_simpleondemand.c | 33 +++++++++++++++++-------------- include/linux/devfreq.h | 7 +++++++ 3 files changed, 30 insertions(+), 15 deletions(-)