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sched/fair: Add eas (& cas) specific rq, sd and task stats

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The statistic counter are placed in the eas (& cas) wakeup path. Each
of them has one representation for the runqueue (rq), the sched_domain
(sd) and the task.
A task counter is always incremented. A rq counter is always
incremented for the rq the scheduler is currently running on. A sd
counter is only incremented if a relation to a sd exists.

The counters are exposed:

(1) In /proc/schedstat for rq's and sd's:

$ cat /proc/schedstat
...
cpu0 71422 0 2321254 ...
eas  44144 0 0 19446 0 24698 568435 51621 156932 133 222011 17459 120279 516814 83 0 156962 359235 176439 139981
  <- runqueue for cpu0
...
domain0 3 42430 42331 ...
eas 0 0 0 14200 0 0 0 0 0 0 0 0 0 0 0 0 0 0 66355 0  <- MC sched domain for cpu0
...

The per-cpu eas vector has the following elements:

sis_attempts  sis_idle   sis_cache_affine sis_suff_cap    sis_idle_cpu    sis_count               ||
secb_attempts secb_sync  secb_idle_bt     secb_insuff_cap secb_no_nrg_sav secb_nrg_sav secb_count ||
fbt_attempts  fbt_no_cpu fbt_no_sd        fbt_pref_idle   fbt_count                               ||
cas_attempts  cas_count

The following relations exist between these counters (from cpu0 eas
vector above):

sis_attempts = sis_idle + sis_cache_affine + sis_suff_cap + sis_idle_cpu + sis_count

44144        = 0        + 0                + 19446        + 0            + 24698

secb_attempts = secb_sync + secb_idle_bt + secb_insuff_cap + secb_no_nrg_sav + secb_nrg_sav + secb_count

568435        = 51621     + 156932       + 133             + 222011          + 17459        + 120279

fbt_attempts = fbt_no_cpu + fbt_no_sd + fbt_pref_idle + fbt_count + (return -1)

516814       = 83         + 0         + 156962        + 359235    + (534)

cas_attempts = cas_count + (return -1 or smp_processor_id())

176439       = 139981    + (36458)

(2) In /proc/$PROCESS_PID/task/$TASK_PID/sched for a task.

example: main thread of system_server

$ cat /proc/1083/task/1083/sched

...
se.statistics.nr_wakeups_sis_attempts        :                  945
se.statistics.nr_wakeups_sis_idle            :                    0
se.statistics.nr_wakeups_sis_cache_affine    :                    0
se.statistics.nr_wakeups_sis_suff_cap        :                  219
se.statistics.nr_wakeups_sis_idle_cpu        :                    0
se.statistics.nr_wakeups_sis_count           :                  726
se.statistics.nr_wakeups_secb_attempts       :                10376
se.statistics.nr_wakeups_secb_sync           :                 1462
se.statistics.nr_wakeups_secb_idle_bt        :                 6984
se.statistics.nr_wakeups_secb_insuff_cap     :                    3
se.statistics.nr_wakeups_secb_no_nrg_sav     :                  927
se.statistics.nr_wakeups_secb_nrg_sav        :                  206
se.statistics.nr_wakeups_secb_count          :                  794
se.statistics.nr_wakeups_fbt_attempts        :                 8914
se.statistics.nr_wakeups_fbt_no_cpu          :                    0
se.statistics.nr_wakeups_fbt_no_sd           :                    0
se.statistics.nr_wakeups_fbt_pref_idle       :                 6987
se.statistics.nr_wakeups_fbt_count           :                 1554
se.statistics.nr_wakeups_cas_attempts        :                 3107
se.statistics.nr_wakeups_cas_count           :                 1195
...

The same relation between the counters as in the per-cpu case apply.

Change-Id: Ie7d01267c78a3f41f60a3ef52917d5a5d463f195
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
This commit is contained in:
Dietmar Eggemann 2017-03-22 18:23:13 +00:00 • committed by Andres Oportus
parent aa8882923a
commit 4b85765a3d
5 changed files with 228 additions and 37 deletions
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62
include/linux/sched.h
View file

@ -1065,6 +1065,37 @@ unsigned long capacity_curr_of(int cpu);
struct sched_group;
struct eas_stats {
/* select_idle_sibling() stats */
u64 sis_attempts;
u64 sis_idle;
u64 sis_cache_affine;
u64 sis_suff_cap;
u64 sis_idle_cpu;
u64 sis_count;
/* select_energy_cpu_brute() stats */
u64 secb_attempts;
u64 secb_sync;
u64 secb_idle_bt;
u64 secb_insuff_cap;
u64 secb_no_nrg_sav;
u64 secb_nrg_sav;
u64 secb_count;
/* find_best_target() stats */
u64 fbt_attempts;
u64 fbt_no_cpu;
u64 fbt_no_sd;
u64 fbt_pref_idle;
u64 fbt_count;
/* cas */
/* select_task_rq_fair() stats */
u64 cas_attempts;
u64 cas_count;
};
struct sched_domain {
/* These fields must be setup */
struct sched_domain *parent; /* top domain must be null terminated */
@ -1125,6 +1156,8 @@ struct sched_domain {
unsigned int ttwu_wake_remote;
unsigned int ttwu_move_affine;
unsigned int ttwu_move_balance;
struct eas_stats eas_stats;
#endif
#ifdef CONFIG_SCHED_DEBUG
char *name;
@ -1283,6 +1316,35 @@ struct sched_statistics {
u64 nr_wakeups_affine_attempts;
u64 nr_wakeups_passive;
u64 nr_wakeups_idle;
/* select_idle_sibling() */
u64 nr_wakeups_sis_attempts;
u64 nr_wakeups_sis_idle;
u64 nr_wakeups_sis_cache_affine;
u64 nr_wakeups_sis_suff_cap;
u64 nr_wakeups_sis_idle_cpu;
u64 nr_wakeups_sis_count;
/* energy_aware_wake_cpu() */
u64 nr_wakeups_secb_attempts;
u64 nr_wakeups_secb_sync;
u64 nr_wakeups_secb_idle_bt;
u64 nr_wakeups_secb_insuff_cap;
u64 nr_wakeups_secb_no_nrg_sav;
u64 nr_wakeups_secb_nrg_sav;
u64 nr_wakeups_secb_count;
/* find_best_target() */
u64 nr_wakeups_fbt_attempts;
u64 nr_wakeups_fbt_no_cpu;
u64 nr_wakeups_fbt_no_sd;
u64 nr_wakeups_fbt_pref_idle;
u64 nr_wakeups_fbt_count;
/* cas */
/* select_task_rq_fair() */
u64 nr_wakeups_cas_attempts;
u64 nr_wakeups_cas_count;
};
#endif

26
kernel/sched/debug.c
View file

@ -597,6 +597,32 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
P(se.statistics.nr_wakeups_affine_attempts);
P(se.statistics.nr_wakeups_passive);
P(se.statistics.nr_wakeups_idle);
/* eas */
/* select_idle_sibling() */
P(se.statistics.nr_wakeups_sis_attempts);
P(se.statistics.nr_wakeups_sis_idle);
P(se.statistics.nr_wakeups_sis_cache_affine);
P(se.statistics.nr_wakeups_sis_suff_cap);
P(se.statistics.nr_wakeups_sis_idle_cpu);
P(se.statistics.nr_wakeups_sis_count);
/* select_energy_cpu_brute() */
P(se.statistics.nr_wakeups_secb_attempts);
P(se.statistics.nr_wakeups_secb_sync);
P(se.statistics.nr_wakeups_secb_idle_bt);
P(se.statistics.nr_wakeups_secb_insuff_cap);
P(se.statistics.nr_wakeups_secb_no_nrg_sav);
P(se.statistics.nr_wakeups_secb_nrg_sav);
P(se.statistics.nr_wakeups_secb_count);
/* find_best_target() */
P(se.statistics.nr_wakeups_fbt_attempts);
P(se.statistics.nr_wakeups_fbt_no_cpu);
P(se.statistics.nr_wakeups_fbt_no_sd);
P(se.statistics.nr_wakeups_fbt_pref_idle);
P(se.statistics.nr_wakeups_fbt_count);
/* cas */
/* select_task_rq_fair() */
P(se.statistics.nr_wakeups_cas_attempts);
P(se.statistics.nr_wakeups_cas_count);
{
u64 avg_atom, avg_per_cpu;

152
kernel/sched/fair.c
View file

@ -6059,15 +6059,24 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
int best_idle_cstate = INT_MAX;
unsigned long best_idle_capacity = ULONG_MAX;
schedstat_inc(p, se.statistics.nr_wakeups_sis_attempts);
schedstat_inc(this_rq(), eas_stats.sis_attempts);
if (!sysctl_sched_cstate_aware) {
if (idle_cpu(target))
if (idle_cpu(target)) {
schedstat_inc(p, se.statistics.nr_wakeups_sis_idle);
schedstat_inc(this_rq(), eas_stats.sis_idle);
return target;
}
/*
* If the prevous cpu is cache affine and idle, don't be stupid.
*/
if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev))
if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev)) {
schedstat_inc(p, se.statistics.nr_wakeups_sis_cache_affine);
schedstat_inc(this_rq(), eas_stats.sis_cache_affine);
return prev;
}
}
/*
@ -6091,8 +6100,12 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
if (new_usage > capacity_orig || !idle_cpu(i))
goto next;
if (i == target && new_usage <= capacity_curr_of(target))
if (i == target && new_usage <= capacity_curr_of(target)) {
schedstat_inc(p, se.statistics.nr_wakeups_sis_suff_cap);
schedstat_inc(this_rq(), eas_stats.sis_suff_cap);
schedstat_inc(sd, eas_stats.sis_suff_cap);
return target;
}
if (idle_idx < best_idle_cstate &&
capacity_orig <= best_idle_capacity) {
@ -6109,6 +6122,9 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
target = cpumask_first_and(sched_group_cpus(sg),
tsk_cpus_allowed(p));
schedstat_inc(p, se.statistics.nr_wakeups_sis_idle_cpu);
schedstat_inc(this_rq(), eas_stats.sis_idle_cpu);
schedstat_inc(sd, eas_stats.sis_idle_cpu);
goto done;
}
next:
@ -6120,6 +6136,9 @@ next:
target = best_idle_cpu;
done:
schedstat_inc(p, se.statistics.nr_wakeups_sis_count);
schedstat_inc(this_rq(), eas_stats.sis_count);
return target;
}
@ -6146,13 +6165,22 @@ static inline int find_best_target(struct task_struct *p, bool boosted, bool pre
struct sched_group *sg;
int cpu = start_cpu(boosted);
if (cpu < 0)
schedstat_inc(p, se.statistics.nr_wakeups_fbt_attempts);
schedstat_inc(this_rq(), eas_stats.fbt_attempts);
if (cpu < 0) {
schedstat_inc(p, se.statistics.nr_wakeups_fbt_no_cpu);
schedstat_inc(this_rq(), eas_stats.fbt_no_cpu);
return target_cpu;
}
sd = rcu_dereference(per_cpu(sd_ea, cpu));
if (!sd)
if (!sd) {
schedstat_inc(p, se.statistics.nr_wakeups_fbt_no_sd);
schedstat_inc(this_rq(), eas_stats.fbt_no_sd);
return target_cpu;
}
sg = sd->groups;
@ -6191,8 +6219,11 @@ static inline int find_best_target(struct task_struct *p, bool boosted, bool pre
* Unconditionally favoring tasks that prefer idle cpus to
* improve latency.
*/
if (idle_cpu(i) && prefer_idle)
if (idle_cpu(i) && prefer_idle) {
schedstat_inc(p, se.statistics.nr_wakeups_fbt_pref_idle);
schedstat_inc(this_rq(), eas_stats.fbt_pref_idle);
return i;
}
cur_capacity = capacity_curr_of(i);
@ -6228,6 +6259,11 @@ static inline int find_best_target(struct task_struct *p, bool boosted, bool pre
if (target_cpu < 0)
target_cpu = best_idle_cpu >= 0 ? best_idle_cpu : backup_cpu;
if (target_cpu >= 0) {
schedstat_inc(p, se.statistics.nr_wakeups_fbt_count);
schedstat_inc(this_rq(), eas_stats.fbt_count);
}
return target_cpu;
}
@ -6279,11 +6315,17 @@ static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync
int target_cpu = prev_cpu, tmp_target;
bool boosted, prefer_idle;
schedstat_inc(p, se.statistics.nr_wakeups_secb_attempts);
schedstat_inc(this_rq(), eas_stats.secb_attempts);
if (sysctl_sched_sync_hint_enable && sync) {
int cpu = smp_processor_id();
if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) {
schedstat_inc(p, se.statistics.nr_wakeups_secb_sync);
schedstat_inc(this_rq(), eas_stats.secb_sync);
return cpu;
}
}
rcu_read_lock();
@ -6303,8 +6345,11 @@ static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync
goto unlock;
if (tmp_target >= 0) {
target_cpu = tmp_target;
if ((boosted || prefer_idle) && idle_cpu(target_cpu))
if ((boosted || prefer_idle) && idle_cpu(target_cpu)) {
schedstat_inc(p, se.statistics.nr_wakeups_secb_idle_bt);
schedstat_inc(this_rq(), eas_stats.secb_idle_bt);
goto unlock;
}
}
if (target_cpu != prev_cpu) {
@ -6316,15 +6361,30 @@ static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync
};
/* Not enough spare capacity on previous cpu */
if (cpu_overutilized(prev_cpu))
if (cpu_overutilized(prev_cpu)) {
schedstat_inc(p, se.statistics.nr_wakeups_secb_insuff_cap);
schedstat_inc(this_rq(), eas_stats.secb_insuff_cap);
goto unlock;
}
if (energy_diff(&eenv) >= 0)
if (energy_diff(&eenv) >= 0) {
schedstat_inc(p, se.statistics.nr_wakeups_secb_no_nrg_sav);
schedstat_inc(this_rq(), eas_stats.secb_no_nrg_sav);
target_cpu = prev_cpu;
goto unlock;
}
schedstat_inc(p, se.statistics.nr_wakeups_secb_nrg_sav);
schedstat_inc(this_rq(), eas_stats.secb_nrg_sav);
goto unlock;
}
schedstat_inc(p, se.statistics.nr_wakeups_secb_count);
schedstat_inc(this_rq(), eas_stats.secb_count);
unlock:
rcu_read_unlock();
return target_cpu;
}
@ -6387,39 +6447,57 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
} else while (sd) {
struct sched_group *group;
int weight;
} else {
int wu = sd_flag & SD_BALANCE_WAKE;
int cas_cpu = -1;
if (!(sd->flags & sd_flag)) {
sd = sd->child;
continue;
if (wu) {
schedstat_inc(p, se.statistics.nr_wakeups_cas_attempts);
schedstat_inc(this_rq(), eas_stats.cas_attempts);
}
group = find_idlest_group(sd, p, cpu, sd_flag);
if (!group) {
sd = sd->child;
continue;
while (sd) {
struct sched_group *group;
int weight;
if (wu)
schedstat_inc(sd, eas_stats.cas_attempts);
if (!(sd->flags & sd_flag)) {
sd = sd->child;
continue;
}
group = find_idlest_group(sd, p, cpu, sd_flag);
if (!group) {
sd = sd->child;
continue;
}
new_cpu = find_idlest_cpu(group, p, cpu);
if (new_cpu == -1 || new_cpu == cpu) {
/* Now try balancing at a lower domain level of cpu */
sd = sd->child;
continue;
}
/* Now try balancing at a lower domain level of new_cpu */
cpu = cas_cpu = new_cpu;
weight = sd->span_weight;
sd = NULL;
for_each_domain(cpu, tmp) {
if (weight <= tmp->span_weight)
break;
if (tmp->flags & sd_flag)
sd = tmp;
}
/* while loop will break here if sd == NULL */
}
new_cpu = find_idlest_cpu(group, p, cpu);
if (new_cpu == -1 || new_cpu == cpu) {
/* Now try balancing at a lower domain level of cpu */
sd = sd->child;
continue;
if (wu && (cas_cpu >= 0)) {
schedstat_inc(p, se.statistics.nr_wakeups_cas_count);
schedstat_inc(this_rq(), eas_stats.cas_count);
}
/* Now try balancing at a lower domain level of new_cpu */
cpu = new_cpu;
weight = sd->span_weight;
sd = NULL;
for_each_domain(cpu, tmp) {
if (weight <= tmp->span_weight)
break;
if (tmp->flags & sd_flag)
sd = tmp;
}
/* while loop will break here if sd == NULL */
}
rcu_read_unlock();

2
kernel/sched/sched.h
View file

@ -734,6 +734,8 @@ struct rq {
/* try_to_wake_up() stats */
unsigned int ttwu_count;
unsigned int ttwu_local;
struct eas_stats eas_stats;
#endif
#ifdef CONFIG_SMP

23
kernel/sched/stats.c
View file

@ -12,6 +12,26 @@
*/
#define SCHEDSTAT_VERSION 15
static inline void show_easstat(struct seq_file *seq, struct eas_stats *stats)
{
/* eas-specific runqueue stats */
seq_printf(seq, "eas %llu %llu %llu %llu %llu %llu ",
stats->sis_attempts, stats->sis_idle, stats->sis_cache_affine,
stats->sis_suff_cap, stats->sis_idle_cpu, stats->sis_count);
seq_printf(seq, "%llu %llu %llu %llu %llu %llu %llu ",
stats->secb_attempts, stats->secb_sync, stats->secb_idle_bt,
stats->secb_insuff_cap, stats->secb_no_nrg_sav,
stats->secb_nrg_sav, stats->secb_count);
seq_printf(seq, "%llu %llu %llu %llu %llu ",
stats->fbt_attempts, stats->fbt_no_cpu, stats->fbt_no_sd,
stats->fbt_pref_idle, stats->fbt_count);
seq_printf(seq, "%llu %llu\n",
stats->cas_attempts, stats->cas_count);
}
static int show_schedstat(struct seq_file *seq, void *v)
{
int cpu;
@ -39,6 +59,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
seq_printf(seq, "\n");
show_easstat(seq, &rq->eas_stats);
#ifdef CONFIG_SMP
/* domain-specific stats */
rcu_read_lock();
@ -66,6 +87,8 @@ static int show_schedstat(struct seq_file *seq, void *v)
sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
sd->ttwu_wake_remote, sd->ttwu_move_affine,
sd->ttwu_move_balance);
show_easstat(seq, &sd->eas_stats);
}
rcu_read_unlock();
#endif