diff options
| -rw-r--r-- | kernel/sched/tune.c | 321 | ||||
| -rw-r--r-- | kernel/sched/tune.h | 7 |
2 files changed, 328 insertions, 0 deletions
diff --git a/kernel/sched/tune.c b/kernel/sched/tune.c index 3253a8732ba5..f4fbbcd28373 100644 --- a/kernel/sched/tune.c +++ b/kernel/sched/tune.c @@ -1,7 +1,9 @@ #include <linux/cgroup.h> #include <linux/err.h> +#include <linux/kernel.h> #include <linux/percpu.h> #include <linux/printk.h> +#include <linux/reciprocal_div.h> #include <linux/rcupdate.h> #include <linux/slab.h> @@ -9,6 +11,84 @@ unsigned int sysctl_sched_cfs_boost __read_mostly; +/* + * System energy normalization constants + */ +static struct target_nrg { + unsigned long min_power; + unsigned long max_power; + struct reciprocal_value rdiv; +} schedtune_target_nrg; + +/* Performance Boost region (B) threshold params */ +static int perf_boost_idx; + +/* Performance Constraint region (C) threshold params */ +static int perf_constrain_idx; + +/** + * Performance-Energy (P-E) Space thresholds constants + */ +struct threshold_params { + int nrg_gain; + int cap_gain; +}; + +/* + * System specific P-E space thresholds constants + */ +static struct threshold_params +threshold_gains[] = { + { 0, 4 }, /* >= 0% */ + { 0, 4 }, /* >= 10% */ + { 1, 4 }, /* >= 20% */ + { 2, 4 }, /* >= 30% */ + { 3, 4 }, /* >= 40% */ + { 4, 3 }, /* >= 50% */ + { 4, 2 }, /* >= 60% */ + { 4, 1 }, /* >= 70% */ + { 4, 0 }, /* >= 80% */ + { 4, 0 } /* >= 90% */ +}; + +static int +__schedtune_accept_deltas(int nrg_delta, int cap_delta, + int perf_boost_idx, int perf_constrain_idx) +{ + int payoff = -INT_MAX; + + /* Performance Boost (B) region */ + if (nrg_delta > 0 && cap_delta > 0) { + /* + * Evaluate "Performance Boost" vs "Energy Increase" + * payoff criteria: + * cap_delta / nrg_delta < cap_gain / nrg_gain + * which is: + * nrg_delta * cap_gain > cap_delta * nrg_gain + */ + payoff = nrg_delta * threshold_gains[perf_boost_idx].cap_gain; + payoff -= cap_delta * threshold_gains[perf_boost_idx].nrg_gain; + return payoff; + } + + /* Performance Constraint (C) region */ + if (nrg_delta < 0 && cap_delta < 0) { + /* + * Evaluate "Performance Boost" vs "Energy Increase" + * payoff criteria: + * cap_delta / nrg_delta > cap_gain / nrg_gain + * which is: + * cap_delta * nrg_gain > nrg_delta * cap_gain + */ + payoff = cap_delta * threshold_gains[perf_constrain_idx].nrg_gain; + payoff -= nrg_delta * threshold_gains[perf_constrain_idx].cap_gain; + return payoff; + } + + /* Default: reject schedule candidate */ + return payoff; +} + #ifdef CONFIG_CGROUP_SCHEDTUNE /* @@ -26,6 +106,11 @@ struct schedtune { /* Boost value for tasks on that SchedTune CGroup */ int boost; + /* Performance Boost (B) region threshold params */ + int perf_boost_idx; + + /* Performance Constraint (C) region threshold params */ + int perf_constrain_idx; }; static inline struct schedtune *css_st(struct cgroup_subsys_state *css) @@ -55,8 +140,37 @@ static inline struct schedtune *parent_st(struct schedtune *st) static struct schedtune root_schedtune = { .boost = 0, + .perf_boost_idx = 0, + .perf_constrain_idx = 0, }; +int +schedtune_accept_deltas(int nrg_delta, int cap_delta, + struct task_struct *task) +{ + struct schedtune *ct; + int perf_boost_idx; + int perf_constrain_idx; + + /* Optimal (O) region */ + if (nrg_delta < 0 && cap_delta > 0) + return INT_MAX; + + /* Suboptimal (S) region */ + if (nrg_delta > 0 && cap_delta < 0) + return -INT_MAX; + + /* Get task specific perf Boost/Constraints indexes */ + rcu_read_lock(); + ct = task_schedtune(task); + perf_boost_idx = ct->perf_boost_idx; + perf_constrain_idx = ct->perf_constrain_idx; + rcu_read_unlock(); + + return __schedtune_accept_deltas(nrg_delta, cap_delta, + perf_boost_idx, perf_constrain_idx); +} + /* * Maximum number of boost groups to support * When per-task boosting is used we still allow only limited number of @@ -396,6 +510,24 @@ struct cgroup_subsys schedtune_cgrp_subsys = { .early_init = 1, }; +#else /* CONFIG_CGROUP_SCHEDTUNE */ + +int +schedtune_accept_deltas(int nrg_delta, int cap_delta, + struct task_struct *task) +{ + /* Optimal (O) region */ + if (nrg_delta < 0 && cap_delta > 0) + return INT_MAX; + + /* Suboptimal (S) region */ + if (nrg_delta > 0 && cap_delta < 0) + return -INT_MAX; + + return __schedtune_accept_deltas(nrg_delta, cap_delta, + perf_boost_idx, perf_constrain_idx); +} + #endif /* CONFIG_CGROUP_SCHEDTUNE */ int @@ -408,6 +540,195 @@ sysctl_sched_cfs_boost_handler(struct ctl_table *table, int write, if (ret || !write) return ret; + /* Performance Boost (B) region threshold params */ + perf_boost_idx = sysctl_sched_cfs_boost; + perf_boost_idx /= 10; + + /* Performance Constraint (C) region threshold params */ + perf_constrain_idx = 100 - sysctl_sched_cfs_boost; + perf_constrain_idx /= 10; + + return 0; +} + +/* + * System energy normalization + * Returns the normalized value, in the range [0..SCHED_LOAD_SCALE], + * corresponding to the specified energy variation. + */ +int +schedtune_normalize_energy(int energy_diff) +{ + u32 normalized_nrg; + int max_delta; + +#ifdef CONFIG_SCHED_DEBUG + /* Check for boundaries */ + max_delta = schedtune_target_nrg.max_power; + max_delta -= schedtune_target_nrg.min_power; + WARN_ON(abs(energy_diff) >= max_delta); +#endif + + /* Do scaling using positive numbers to increase the range */ + normalized_nrg = (energy_diff < 0) ? -energy_diff : energy_diff; + + /* Scale by energy magnitude */ + normalized_nrg <<= SCHED_LOAD_SHIFT; + + /* Normalize on max energy for target platform */ + normalized_nrg = reciprocal_divide( + normalized_nrg, schedtune_target_nrg.rdiv); + + return (energy_diff < 0) ? -normalized_nrg : normalized_nrg; +} + +#ifdef CONFIG_SCHED_DEBUG +static void +schedtune_test_nrg(unsigned long delta_pwr) +{ + unsigned long test_delta_pwr; + unsigned long test_norm_pwr; + int idx; + + /* + * Check normalization constants using some constant system + * energy values + */ + pr_info("schedtune: verify normalization constants...\n"); + for (idx = 0; idx < 6; ++idx) { + test_delta_pwr = delta_pwr >> idx; + + /* Normalize on max energy for target platform */ + test_norm_pwr = reciprocal_divide( + test_delta_pwr << SCHED_LOAD_SHIFT, + schedtune_target_nrg.rdiv); + + pr_info("schedtune: max_pwr/2^%d: %4lu => norm_pwr: %5lu\n", + idx, test_delta_pwr, test_norm_pwr); + } +} +#else +#define schedtune_test_nrg(delta_pwr) +#endif + +/* + * Compute the min/max power consumption of a cluster and all its CPUs + */ +static void +schedtune_add_cluster_nrg( + struct sched_domain *sd, + struct sched_group *sg, + struct target_nrg *ste) +{ + struct sched_domain *sd2; + struct sched_group *sg2; + + struct cpumask *cluster_cpus; + char str[32]; + + unsigned long min_pwr; + unsigned long max_pwr; + int cpu; + + /* Get Cluster energy using EM data for the first CPU */ + cluster_cpus = sched_group_cpus(sg); + snprintf(str, 32, "CLUSTER[%*pbl]", + cpumask_pr_args(cluster_cpus)); + + min_pwr = sg->sge->idle_states[sg->sge->nr_idle_states - 1].power; + max_pwr = sg->sge->cap_states[sg->sge->nr_cap_states - 1].power; + pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n", + str, min_pwr, max_pwr); + + /* + * Keep track of this cluster's energy in the computation of the + * overall system energy + */ + ste->min_power += min_pwr; + ste->max_power += max_pwr; + + /* Get CPU energy using EM data for each CPU in the group */ + for_each_cpu(cpu, cluster_cpus) { + /* Get a SD view for the specific CPU */ + for_each_domain(cpu, sd2) { + /* Get the CPU group */ + sg2 = sd2->groups; + min_pwr = sg2->sge->idle_states[sg2->sge->nr_idle_states - 1].power; + max_pwr = sg2->sge->cap_states[sg2->sge->nr_cap_states - 1].power; + + ste->min_power += min_pwr; + ste->max_power += max_pwr; + + snprintf(str, 32, "CPU[%d]", cpu); + pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n", + str, min_pwr, max_pwr); + + /* + * Assume we have EM data only at the CPU and + * the upper CLUSTER level + */ + BUG_ON(!cpumask_equal( + sched_group_cpus(sg), + sched_group_cpus(sd2->parent->groups) + )); + break; + } + } +} + +/* + * Initialize the constants required to compute normalized energy. + * The values of these constants depends on the EM data for the specific + * target system and topology. + * Thus, this function is expected to be called by the code + * that bind the EM to the topology information. + */ +static int +schedtune_init_late(void) +{ + struct target_nrg *ste = &schedtune_target_nrg; + unsigned long delta_pwr = 0; + struct sched_domain *sd; + struct sched_group *sg; + + pr_info("schedtune: init normalization constants...\n"); + ste->max_power = 0; + ste->min_power = 0; + + rcu_read_lock(); + + /* + * When EAS is in use, we always have a pointer to the highest SD + * which provides EM data. + */ + sd = rcu_dereference(per_cpu(sd_ea, cpumask_first(cpu_online_mask))); + if (!sd) { + pr_info("schedtune: no energy model data\n"); + goto nodata; + } + + sg = sd->groups; + do { + schedtune_add_cluster_nrg(sd, sg, ste); + } while (sg = sg->next, sg != sd->groups); + + rcu_read_unlock(); + + pr_info("schedtune: %-17s min_pwr: %5lu max_pwr: %5lu\n", + "SYSTEM", ste->min_power, ste->max_power); + + /* Compute normalization constants */ + delta_pwr = ste->max_power - ste->min_power; + ste->rdiv = reciprocal_value(delta_pwr); + pr_info("schedtune: using normalization constants mul: %u sh1: %u sh2: %u\n", + ste->rdiv.m, ste->rdiv.sh1, ste->rdiv.sh2); + + schedtune_test_nrg(delta_pwr); return 0; + +nodata: + rcu_read_unlock(); + return -EINVAL; } +late_initcall(schedtune_init_late); diff --git a/kernel/sched/tune.h b/kernel/sched/tune.h index d756ce7b06e0..f7273a5d994a 100644 --- a/kernel/sched/tune.h +++ b/kernel/sched/tune.h @@ -16,9 +16,16 @@ void schedtune_dequeue_task(struct task_struct *p, int cpu); #endif /* CONFIG_CGROUP_SCHEDTUNE */ +int schedtune_normalize_energy(int energy); +int schedtune_accept_deltas(int nrg_delta, int cap_delta, + struct task_struct *task); + #else /* CONFIG_SCHED_TUNE */ #define schedtune_enqueue_task(task, cpu) do { } while (0) #define schedtune_dequeue_task(task, cpu) do { } while (0) +#define schedtune_normalize_energy(energy) energy +#define schedtune_accept_deltas(nrg_delta, cap_delta, task) nrg_delta + #endif /* CONFIG_SCHED_TUNE */ |