diff options
| author | Patrick Bellasi <patrick.bellasi@arm.com> | 2016-01-14 18:35:13 +0000 |
|---|---|---|
| committer | Punit Agrawal <punit.agrawal@arm.com> | 2016-03-21 14:57:36 +0000 |
| commit | 81cc39cc812f53517f0bf4881795e2917aace6c5 (patch) | |
| tree | 2695cd467cf3d1f23838d88eb60d5759da63c33a | |
| parent | aa0c021706f3049cca12f22bdaca4ce56157e056 (diff) | |
sched/fair: keep track of energy/capacity variations
The current EAS implementation does not allow "to boost" tasks
performances, for example by running them at an higher OPP (or a more
capable CPU), even if that could require a "reasonable" increase in
energy consumption. To defined how much reasonable is an energy
increase with respect to a required boost value, it is required to
define and compute a trade-off between the expected energy and
performance variations.
However, the current EAS implementation considers only energy variations
while completely disregard the impact on performance for the selection
of a certain schedule candidate.
This patch extends the eenv energy environment to keep track of both
energy and performance deltas which are implied by the activation of a
schedule candidate.
The performance variation is estimated considering the different
capacities of the CPUs in which the task could be scheduled. The idea is
that while running on a CPU with higher capacity (e.g. higher operating
point) the task could (potentially) complete faster and thus get better
performance.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
| -rw-r--r-- | kernel/sched/fair.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f582d58daea5..3b80ad01aa8b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4706,6 +4706,16 @@ struct energy_env { int src_cpu; int dst_cpu; int energy; + struct { + int before; + int after; + int diff; + } nrg; + struct { + int before; + int after; + int delta; + } cap; }; /* @@ -4872,6 +4882,22 @@ static int sched_group_energy(struct energy_env *eenv) eenv->sg_cap = sg; cap_idx = find_new_capacity(eenv, sg->sge); + + if (sg->group_weight == 1) { + /* Remove capacity of src CPU (before task move) */ + if (eenv->util_delta == 0 && + cpumask_test_cpu(eenv->src_cpu, sched_group_cpus(sg))) { + eenv->cap.before = sg->sge->cap_states[cap_idx].cap; + eenv->cap.delta -= eenv->cap.before; + } + /* Add capacity of dst CPU (after task move) */ + if (eenv->util_delta != 0 && + cpumask_test_cpu(eenv->dst_cpu, sched_group_cpus(sg))) { + eenv->cap.after = sg->sge->cap_states[cap_idx].cap; + eenv->cap.delta += eenv->cap.after; + } + } + idle_idx = group_idle_state(sg); group_util = group_norm_util(eenv, sg); sg_busy_energy = (group_util * sg->sge->cap_states[cap_idx].power) @@ -4920,6 +4946,8 @@ static int energy_diff(struct energy_env *eenv) .util_delta = 0, .src_cpu = eenv->src_cpu, .dst_cpu = eenv->dst_cpu, + .nrg = { 0, 0, 0 }, + .cap = { 0, 0, 0 }, }; if (eenv->src_cpu == eenv->dst_cpu) @@ -4941,13 +4969,21 @@ static int energy_diff(struct energy_env *eenv) return 0; /* Invalid result abort */ energy_before += eenv_before.energy; + /* Keep track of SRC cpu (before) capacity */ + eenv->cap.before = eenv_before.cap.before; + eenv->cap.delta = eenv_before.cap.delta; + if (sched_group_energy(eenv)) return 0; /* Invalid result abort */ energy_after += eenv->energy; } } while (sg = sg->next, sg != sd->groups); - return energy_after-energy_before; + eenv->nrg.before = energy_before; + eenv->nrg.after = energy_after; + eenv->nrg.diff = eenv->nrg.after - eenv->nrg.before; + + return eenv->nrg.diff; } /* |