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

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

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>