From: Morten Rasmussen Date: Fri, 2 Jan 2015 14:21:56 +0000 (+0000) Subject: sched: Extend sched_group_energy to test load-balancing decisions X-Git-Tag: firefly_0821_release~2507^2~49 X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=4a535730fb7c9afad6b0bbc96dc8dc3d1f6ae0ed;p=firefly-linux-kernel-4.4.55.git sched: Extend sched_group_energy to test load-balancing decisions Extended sched_group_energy() to support energy prediction with usage (tasks) added/removed from a specific cpu or migrated between a pair of cpus. Useful for load-balancing decision making. cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Morten Rasmussen --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 49f7567c6b07..f3de37414a66 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4688,12 +4688,21 @@ static unsigned long capacity_curr_of(int cpu) * capacity_orig) as it useful for predicting the capacity required after task * migrations (scheduler-driven DVFS). */ -static unsigned long cpu_util(int cpu) +static unsigned long __cpu_util(int cpu, int delta) { unsigned long util = cpu_rq(cpu)->cfs.avg.util_avg; unsigned long capacity = capacity_orig_of(cpu); - return (util >= capacity) ? capacity : util; + delta += util; + if (delta < 0) + return 0; + + return (delta >= capacity) ? capacity : delta; +} + +static unsigned long cpu_util(int cpu) +{ + return __cpu_util(cpu, 0); } static inline bool energy_aware(void) @@ -4701,8 +4710,18 @@ static inline bool energy_aware(void) return sched_feat(ENERGY_AWARE); } +struct energy_env { + struct sched_group *sg_top; + struct sched_group *sg_cap; + int cap_idx; + int util_delta; + int src_cpu; + int dst_cpu; + int energy; +}; + /* - * cpu_norm_util() returns the cpu util relative to a specific capacity, + * __cpu_norm_util() returns the cpu util relative to a specific capacity, * i.e. it's busy ratio, in the range [0..SCHED_LOAD_SCALE] which is useful for * energy calculations. Using the scale-invariant util returned by * cpu_util() and approximating scale-invariant util by: @@ -4715,9 +4734,9 @@ static inline bool energy_aware(void) * * norm_util = running_time/time ~ util/capacity */ -static unsigned long cpu_norm_util(int cpu, unsigned long capacity) +static unsigned long __cpu_norm_util(int cpu, unsigned long capacity, int delta) { - int util = cpu_util(cpu); + int util = __cpu_util(cpu, delta); if (util >= capacity) return SCHED_CAPACITY_SCALE; @@ -4725,13 +4744,25 @@ static unsigned long cpu_norm_util(int cpu, unsigned long capacity) return (util << SCHED_CAPACITY_SHIFT)/capacity; } -static unsigned long group_max_util(struct sched_group *sg) +static int calc_util_delta(struct energy_env *eenv, int cpu) { - int i; + if (cpu == eenv->src_cpu) + return -eenv->util_delta; + if (cpu == eenv->dst_cpu) + return eenv->util_delta; + return 0; +} + +static +unsigned long group_max_util(struct energy_env *eenv) +{ + int i, delta; unsigned long max_util = 0; - for_each_cpu(i, sched_group_cpus(sg)) - max_util = max(max_util, cpu_util(i)); + for_each_cpu(i, sched_group_cpus(eenv->sg_cap)) { + delta = calc_util_delta(eenv, i); + max_util = max(max_util, __cpu_util(i, delta)); + } return max_util; } @@ -4745,31 +4776,36 @@ static unsigned long group_max_util(struct sched_group *sg) * latter is used as the estimate as it leads to a more pessimistic energy * estimate (more busy). */ -static unsigned long group_norm_util(struct sched_group *sg, int cap_idx) +static unsigned +long group_norm_util(struct energy_env *eenv, struct sched_group *sg) { - int i; + int i, delta; unsigned long util_sum = 0; - unsigned long capacity = sg->sge->cap_states[cap_idx].cap; + unsigned long capacity = sg->sge->cap_states[eenv->cap_idx].cap; - for_each_cpu(i, sched_group_cpus(sg)) - util_sum += cpu_norm_util(i, capacity); + for_each_cpu(i, sched_group_cpus(sg)) { + delta = calc_util_delta(eenv, i); + util_sum += __cpu_norm_util(i, capacity, delta); + } if (util_sum > SCHED_CAPACITY_SCALE) return SCHED_CAPACITY_SCALE; return util_sum; } -static int find_new_capacity(struct sched_group *sg, +static int find_new_capacity(struct energy_env *eenv, const struct sched_group_energy const *sge) { int idx; - unsigned long util = group_max_util(sg); + unsigned long util = group_max_util(eenv); for (idx = 0; idx < sge->nr_cap_states; idx++) { if (sge->cap_states[idx].cap >= util) - return idx; + break; } + eenv->cap_idx = idx; + return idx; } @@ -4783,16 +4819,16 @@ static int find_new_capacity(struct sched_group *sg, * This can probably be done in a faster but more complex way. * Note: sched_group_energy() may fail when racing with sched_domain updates. */ -static int sched_group_energy(struct sched_group *sg_top) +static int sched_group_energy(struct energy_env *eenv) { struct sched_domain *sd; int cpu, total_energy = 0; struct cpumask visit_cpus; struct sched_group *sg; - WARN_ON(!sg_top->sge); + WARN_ON(!eenv->sg_top->sge); - cpumask_copy(&visit_cpus, sched_group_cpus(sg_top)); + cpumask_copy(&visit_cpus, sched_group_cpus(eenv->sg_top)); while (!cpumask_empty(&visit_cpus)) { struct sched_group *sg_shared_cap = NULL; @@ -4824,17 +4860,16 @@ static int sched_group_energy(struct sched_group *sg_top) break; do { - struct sched_group *sg_cap_util; unsigned long group_util; int sg_busy_energy, sg_idle_energy, cap_idx; if (sg_shared_cap && sg_shared_cap->group_weight >= sg->group_weight) - sg_cap_util = sg_shared_cap; + eenv->sg_cap = sg_shared_cap; else - sg_cap_util = sg; + eenv->sg_cap = sg; - cap_idx = find_new_capacity(sg_cap_util, sg->sge); - group_util = group_norm_util(sg, cap_idx); + cap_idx = find_new_capacity(eenv, sg->sge); + group_util = group_norm_util(eenv, sg); sg_busy_energy = (group_util * sg->sge->cap_states[cap_idx].power) >> SCHED_CAPACITY_SHIFT; sg_idle_energy = ((SCHED_LOAD_SCALE-group_util) * sg->sge->idle_states[0].power) @@ -4845,7 +4880,7 @@ static int sched_group_energy(struct sched_group *sg_top) if (!sd->child) cpumask_xor(&visit_cpus, &visit_cpus, sched_group_cpus(sg)); - if (cpumask_equal(sched_group_cpus(sg), sched_group_cpus(sg_top))) + if (cpumask_equal(sched_group_cpus(sg), sched_group_cpus(eenv->sg_top))) goto next_cpu; } while (sg = sg->next, sg != sd->groups); @@ -4854,7 +4889,8 @@ next_cpu: continue; } - return total_energy; + eenv->energy = total_energy; + return 0; } /*