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pmdomain: core: Add residency reflection for domain-idlestates to debugfs

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For regular cpuidle states we are reflecting over the selected/entered
state to see if the sleep-duration meets the residency for the state. The
output from the reflection is an "above" value to indicate the number of
times the state was too deep and a "below" value for the number of times it
was too shallow.

Let's implement the similar thing for genpd's domain-idlestates along with
genpd's governor and put the information in the genpd's debugfs.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20250314100103.1294715-5-ulf.hansson@linaro.org
This commit is contained in:
Ulf Hansson 2025-03-14 11:00:58 +01:00
parent d0252ba821
commit 0a8a888167
3 changed files with 43 additions and 3 deletions
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40
drivers/pmdomain/core.c
View File

@ -304,10 +304,40 @@ static void genpd_update_accounting(struct generic_pm_domain *genpd)
genpd->accounting_time = now;
}
static void genpd_reflect_residency(struct generic_pm_domain *genpd)
{
struct genpd_governor_data *gd = genpd->gd;
struct genpd_power_state *state, *next_state;
unsigned int state_idx;
s64 sleep_ns, target_ns;
if (!gd || !gd->reflect_residency)
return;
sleep_ns = ktime_to_ns(ktime_sub(ktime_get(), gd->last_enter));
state_idx = genpd->state_idx;
state = &genpd->states[state_idx];
target_ns = state->power_off_latency_ns + state->residency_ns;
if (sleep_ns < target_ns) {
state->above++;
} else if (state_idx < (genpd->state_count -1)) {
next_state = &genpd->states[state_idx + 1];
target_ns = next_state->power_off_latency_ns +
next_state->residency_ns;
if (sleep_ns >= target_ns)
state->below++;
}
gd->reflect_residency = false;
}
#else
static inline void genpd_debug_add(struct generic_pm_domain *genpd) {}
static inline void genpd_debug_remove(struct generic_pm_domain *genpd) {}
static inline void genpd_update_accounting(struct generic_pm_domain *genpd) {}
static inline void genpd_reflect_residency(struct generic_pm_domain *genpd) {}
#endif
static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd,
@ -982,6 +1012,9 @@ static int genpd_power_on(struct generic_pm_domain *genpd, unsigned int depth)
if (genpd_status_on(genpd))
return 0;
/* Reflect over the entered idle-states residency for debugfs. */
genpd_reflect_residency(genpd);
/*
* The list is guaranteed not to change while the loop below is being
* executed, unless one of the parents' .power_on() callbacks fiddles
@ -3517,7 +3550,7 @@ static int idle_states_show(struct seq_file *s, void *data)
if (ret)
return -ERESTARTSYS;
seq_puts(s, "State Time Spent(ms) Usage Rejected\n");
seq_puts(s, "State Time Spent(ms) Usage Rejected Above Below\n");
for (i = 0; i < genpd->state_count; i++) {
struct genpd_power_state *state = &genpd->states[i];
@ -3537,9 +3570,10 @@ static int idle_states_show(struct seq_file *s, void *data)
snprintf(state_name, ARRAY_SIZE(state_name), "S%-13d", i);
do_div(idle_time, NSEC_PER_MSEC);
seq_printf(s, "%-14s %-14llu %-14llu %llu\n",
seq_printf(s, "%-14s %-14llu %-10llu %-10llu %-10llu %llu\n",
state->name ?: state_name, idle_time,
state->usage, state->rejected);
state->usage, state->rejected, state->above,
state->below);
}
genpd_unlock(genpd);

2
drivers/pmdomain/governor.c
View File

@ -392,6 +392,8 @@ static bool cpu_power_down_ok(struct dev_pm_domain *pd)
if (idle_duration_ns >= (genpd->states[i].residency_ns +
genpd->states[i].power_off_latency_ns)) {
genpd->state_idx = i;
genpd->gd->last_enter = now;
genpd->gd->reflect_residency = true;
return true;
}
} while (--i >= 0);

4
include/linux/pm_domain.h
View File

@ -142,6 +142,8 @@ struct genpd_governor_data {
bool max_off_time_changed;
ktime_t next_wakeup;
ktime_t next_hrtimer;
ktime_t last_enter;
bool reflect_residency;
bool cached_power_down_ok;
bool cached_power_down_state_idx;
};
@ -153,6 +155,8 @@ struct genpd_power_state {
s64 residency_ns;
u64 usage;
u64 rejected;
u64 above;
u64 below;
struct fwnode_handle *fwnode;
u64 idle_time;
void *data;