shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-11 13:27:06 +09:00
Code Issues Packages Projects Releases Wiki Activity

ANDROID: sched/fair: Bypass energy computation for prefer_idle tasks

Browse Source 
If the only pre-selected candidate CPU in find_energy_efficient_cpu()
happens to be prev_cpu, there is not point in computing the system
energy since we have nothing to compare it against, so we currently bail
out early. The same logic can be extended when prefer_idle tasks are
routed in the energy-aware wake-up path: if the only candidate is idle
for a prefer_idle task, just select it no matter what the energy impact
is. That should help speeding-up wake-ups of prefer_idle tasks, at least
when find_best_target() is used for them.

Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Change-Id: Idd0e387e4a766061cc05d2584df3a31e4dabfd09
This commit is contained in:
Quentin Perret
2018-05-24 17:35:02 +01:00
parent 1d00c33d8b
commit c06013206c
1 changed files with 10 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
kernel/sched/fair.c
View File

@@ -6997,11 +6997,19 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu, int sy
else
select_max_spare_cap_cpus(sd, candidates, pd, p);
/* Bail out if there is no candidate, or if the only one is prev_cpu */
/* Bail out if no candidate was found. */
weight = cpumask_weight(candidates);
if (!weight || (weight == 1 && cpumask_first(candidates) == prev_cpu))
if (!weight)
goto unlock;
/* If there is only one sensible candidate, select it now. */
cpu = cpumask_first(candidates);
if (weight == 1 && ((schedtune_prefer_idle(p) && idle_cpu(cpu)) ||
(cpu == prev_cpu))) {
best_energy_cpu = cpu;
goto unlock;
}
if (cpumask_test_cpu(prev_cpu, &p->cpus_allowed))
prev_energy = best_energy = compute_energy(p, prev_cpu, pd);
else