From: Vincent Guittot vincent.guittot@linaro.org
commit a2e90611b9f425adbbfcdaa5b5e49958ddf6f61b upstream.
Remove the capacity inversion detection which is now handled by util_fits_cpu() returning -1 when we need to continue to look for a potential CPU with better performance.
This ends up almost reverting patches below except for some comments: commit da07d2f9c153 ("sched/fair: Fixes for capacity inversion detection") commit aa69c36f31aa ("sched/fair: Consider capacity inversion in util_fits_cpu()") commit 44c7b80bffc3 ("sched/fair: Detect capacity inversion")
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lore.kernel.org/r/20230201143628.270912-3-vincent.guittot@linaro.org (cherry picked from commit a2e90611b9f425adbbfcdaa5b5e49958ddf6f61b) Signed-off-by: Qais Yousef (Google) qyousef@layalina.io --- kernel/sched/fair.c | 84 +++----------------------------------------- kernel/sched/sched.h | 19 ---------- 2 files changed, 5 insertions(+), 98 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a45ccee98ab1..612873ec2197 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4464,17 +4464,9 @@ static inline int util_fits_cpu(unsigned long util, * * For uclamp_max, we can tolerate a drop in performance level as the * goal is to cap the task. So it's okay if it's getting less. - * - * In case of capacity inversion we should honour the inverted capacity - * for both uclamp_min and uclamp_max all the time. */ - capacity_orig = cpu_in_capacity_inversion(cpu); - if (capacity_orig) { - capacity_orig_thermal = capacity_orig; - } else { - capacity_orig = capacity_orig_of(cpu); - capacity_orig_thermal = capacity_orig - arch_scale_thermal_pressure(cpu); - } + capacity_orig = capacity_orig_of(cpu); + capacity_orig_thermal = capacity_orig - arch_scale_thermal_pressure(cpu);
/* * We want to force a task to fit a cpu as implied by uclamp_max. @@ -8929,82 +8921,16 @@ static unsigned long scale_rt_capacity(int cpu)
static void update_cpu_capacity(struct sched_domain *sd, int cpu) { - unsigned long capacity_orig = arch_scale_cpu_capacity(cpu); unsigned long capacity = scale_rt_capacity(cpu); struct sched_group *sdg = sd->groups; - struct rq *rq = cpu_rq(cpu);
- rq->cpu_capacity_orig = capacity_orig; + cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(cpu);
if (!capacity) capacity = 1;
- rq->cpu_capacity = capacity; - - /* - * Detect if the performance domain is in capacity inversion state. - * - * Capacity inversion happens when another perf domain with equal or - * lower capacity_orig_of() ends up having higher capacity than this - * domain after subtracting thermal pressure. - * - * We only take into account thermal pressure in this detection as it's - * the only metric that actually results in *real* reduction of - * capacity due to performance points (OPPs) being dropped/become - * unreachable due to thermal throttling. - * - * We assume: - * * That all cpus in a perf domain have the same capacity_orig - * (same uArch). - * * Thermal pressure will impact all cpus in this perf domain - * equally. - */ - if (sched_energy_enabled()) { - unsigned long inv_cap = capacity_orig - thermal_load_avg(rq); - struct perf_domain *pd; - - rcu_read_lock(); - - pd = rcu_dereference(rq->rd->pd); - rq->cpu_capacity_inverted = 0; - - for (; pd; pd = pd->next) { - struct cpumask *pd_span = perf_domain_span(pd); - unsigned long pd_cap_orig, pd_cap; - - /* We can't be inverted against our own pd */ - if (cpumask_test_cpu(cpu_of(rq), pd_span)) - continue; - - cpu = cpumask_any(pd_span); - pd_cap_orig = arch_scale_cpu_capacity(cpu); - - if (capacity_orig < pd_cap_orig) - continue; - - /* - * handle the case of multiple perf domains have the - * same capacity_orig but one of them is under higher - * thermal pressure. We record it as capacity - * inversion. - */ - if (capacity_orig == pd_cap_orig) { - pd_cap = pd_cap_orig - thermal_load_avg(cpu_rq(cpu)); - - if (pd_cap > inv_cap) { - rq->cpu_capacity_inverted = inv_cap; - break; - } - } else if (pd_cap_orig > inv_cap) { - rq->cpu_capacity_inverted = inv_cap; - break; - } - } - - rcu_read_unlock(); - } - - trace_sched_cpu_capacity_tp(rq); + cpu_rq(cpu)->cpu_capacity = capacity; + trace_sched_cpu_capacity_tp(cpu_rq(cpu));
sdg->sgc->capacity = capacity; sdg->sgc->min_capacity = capacity; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 5f18460f62f0..d6d488e8eb55 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1041,7 +1041,6 @@ struct rq {
unsigned long cpu_capacity; unsigned long cpu_capacity_orig; - unsigned long cpu_capacity_inverted;
struct balance_callback *balance_callback;
@@ -2879,24 +2878,6 @@ static inline unsigned long capacity_orig_of(int cpu) return cpu_rq(cpu)->cpu_capacity_orig; }
-/* - * Returns inverted capacity if the CPU is in capacity inversion state. - * 0 otherwise. - * - * Capacity inversion detection only considers thermal impact where actual - * performance points (OPPs) gets dropped. - * - * Capacity inversion state happens when another performance domain that has - * equal or lower capacity_orig_of() becomes effectively larger than the perf - * domain this CPU belongs to due to thermal pressure throttling it hard. - * - * See comment in update_cpu_capacity(). - */ -static inline unsigned long cpu_in_capacity_inversion(int cpu) -{ - return cpu_rq(cpu)->cpu_capacity_inverted; -} - /** * enum cpu_util_type - CPU utilization type * @FREQUENCY_UTIL: Utilization used to select frequency