From: Morten Rasmussen morten.rasmussen@arm.com
Introduces a priority threshold which prevents low priority task from migrating to faster hmp_domains (cpus). This is useful for user-space software which assigns lower task priority to background task.
Signed-off-by: Morten Rasmussen morten.rasmussen@arm.com --- arch/arm/Kconfig | 13 +++++++++++++ kernel/sched/fair.c | 15 +++++++++++++++ 2 files changed, 28 insertions(+)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 5b09684..05de193 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1571,6 +1571,19 @@ config SCHED_HMP !SCHED_AUTOGROUP. Furthermore, normal load-balancing must be disabled between cpus of different type (DISABLE_CPU_SCHED_DOMAIN_BALANCE).
+config SCHED_HMP_PRIO_FILTER + bool "(EXPERIMENTAL) Filter HMP migrations by task priority" + depends on SCHED_HMP + help + Enables task priority based HMP migration filter. Any task with + a NICE value above the threshold will always be on low-power cpus + with less compute capacity. + +config SCHED_HMP_PRIO_FILTER_VAL + int "NICE priority threshold" + default 5 + depends on SCHED_HMP_PRIO_FILTER + config HAVE_ARM_SCU bool help diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 490f1f0..8f0f3b9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3129,9 +3129,12 @@ static int __init hmp_cpu_mask_setup(void) * hmp_down_threshold: max. load allowed for tasks migrating to a slower cpu * The default values (512, 256) offer good responsiveness, but may need * tweaking suit particular needs. + * + * hmp_up_prio: Only up migrate task with high priority (<hmp_up_prio) */ unsigned int hmp_up_threshold = 512; unsigned int hmp_down_threshold = 256; +unsigned int hmp_up_prio = NICE_TO_PRIO(CONFIG_SCHED_HMP_PRIO_FILTER_VAL);
static unsigned int hmp_up_migration(int cpu, struct sched_entity *se); static unsigned int hmp_down_migration(int cpu, struct sched_entity *se); @@ -5491,6 +5494,12 @@ static unsigned int hmp_up_migration(int cpu, struct sched_entity *se) if (hmp_cpu_is_fastest(cpu)) return 0;
+#ifdef CONFIG_SCHED_HMP_PRIO_FILTER + /* Filter by task priority */ + if (p->prio >= hmp_up_prio) + return 0; +#endif + if (cpumask_intersects(&hmp_faster_domain(cpu)->cpus, tsk_cpus_allowed(p)) && se->avg.load_avg_ratio > hmp_up_threshold) { @@ -5507,6 +5516,12 @@ static unsigned int hmp_down_migration(int cpu, struct sched_entity *se) if (hmp_cpu_is_slowest(cpu)) return 0;
+#ifdef CONFIG_SCHED_HMP_PRIO_FILTER + /* Filter by task priority */ + if (p->prio >= hmp_up_prio) + return 1; +#endif + if (cpumask_intersects(&hmp_slower_domain(cpu)->cpus, tsk_cpus_allowed(p)) && se->avg.load_avg_ratio < hmp_down_threshold) {