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Message-ID: <CAM4v1pNpc+dpEd4KZ3k-uTxsu01gKBtusNvppaHeMdvdzf_i+Q@mail.gmail.com>
Date: Fri, 16 May 2014 14:30:57 +0530
From: Preeti Murthy <preeti.lkml@...il.com>
To: Nicolas Pitre <nicolas.pitre@...aro.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Morten Rasmussen <morten.rasmussen@....com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
LKML <linux-kernel@...r.kernel.org>,
Lists linaro-kernel <linaro-kernel@...ts.linaro.org>,
Preeti U Murthy <preeti@...ux.vnet.ibm.com>
Subject: Re: [PATCH 5/6] sched: remove remaining power to the CPU
Hi Nicolas,
You might want to change the subject.
s/sched: remove remaining power to the CPU/
sched: remove remaining usage of cpu *power* .
The subject has to explicitly specify in some way
that it is a change made to the terminology.
Regards
Preeti U Murthy
On Thu, May 15, 2014 at 2:27 AM, Nicolas Pitre <nicolas.pitre@...aro.org> wrote:
> It is better not to think about compute capacity as being equivalent to
> "CPU power". The upcoming "power aware" scheduler may create confusion
> with the notion of energy consumption if "power" is used too liberally.
>
> This is the remaining "power" -> "capacity" rename. Those symbols
> visible to the rest of the kernel are not included yet.
>
> Signed-off-by: Nicolas Pitre <nico@...aro.org>
> ---
> kernel/sched/core.c | 6 +--
> kernel/sched/fair.c | 102 +++++++++++++++++++++++++--------------------------
> kernel/sched/sched.h | 2 +-
> 3 files changed, 55 insertions(+), 55 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index d8ba3ab1c0..00d04e9e7b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5764,7 +5764,7 @@ static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
> /*
> * build_sched_groups will build a circular linked list of the groups
> * covered by the given span, and will set each group's ->cpumask correctly,
> - * and ->cpu_power to 0.
> + * and ->cpu_capacity to 0.
> *
> * Assumes the sched_domain tree is fully constructed
> */
> @@ -6473,7 +6473,7 @@ static int build_sched_domains(const struct cpumask *cpu_map,
> }
> }
>
> - /* Calculate CPU power for physical packages and nodes */
> + /* Calculate CPU capacity for physical packages and nodes */
> for (i = nr_cpumask_bits-1; i >= 0; i--) {
> if (!cpumask_test_cpu(i, cpu_map))
> continue;
> @@ -6923,7 +6923,7 @@ void __init sched_init(void)
> #ifdef CONFIG_SMP
> rq->sd = NULL;
> rq->rd = NULL;
> - rq->cpu_power = SCHED_POWER_SCALE;
> + rq->cpu_capacity = SCHED_POWER_SCALE;
> rq->post_schedule = 0;
> rq->active_balance = 0;
> rq->next_balance = jiffies;
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 6bc1e54d30..06619b52dd 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -1017,7 +1017,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
> static unsigned long weighted_cpuload(const int cpu);
> static unsigned long source_load(int cpu, int type);
> static unsigned long target_load(int cpu, int type);
> -static unsigned long power_of(int cpu);
> +static unsigned long capacity_of(int cpu);
> static long effective_load(struct task_group *tg, int cpu, long wl, long wg);
>
> /* Cached statistics for all CPUs within a node */
> @@ -1046,7 +1046,7 @@ static void update_numa_stats(struct numa_stats *ns, int nid)
>
> ns->nr_running += rq->nr_running;
> ns->load += weighted_cpuload(cpu);
> - ns->compute_capacity += power_of(cpu);
> + ns->compute_capacity += capacity_of(cpu);
>
> cpus++;
> }
> @@ -1185,7 +1185,7 @@ balance:
> dst_load = env->dst_stats.load;
> src_load = env->src_stats.load;
>
> - /* XXX missing power terms */
> + /* XXX missing capacity terms */
> load = task_h_load(env->p);
> dst_load += load;
> src_load -= load;
> @@ -4015,9 +4015,9 @@ static unsigned long target_load(int cpu, int type)
> return max(rq->cpu_load[type-1], total);
> }
>
> -static unsigned long power_of(int cpu)
> +static unsigned long capacity_of(int cpu)
> {
> - return cpu_rq(cpu)->cpu_power;
> + return cpu_rq(cpu)->cpu_capacity;
> }
>
> static unsigned long cpu_avg_load_per_task(int cpu)
> @@ -4260,12 +4260,12 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
> s64 this_eff_load, prev_eff_load;
>
> this_eff_load = 100;
> - this_eff_load *= power_of(prev_cpu);
> + this_eff_load *= capacity_of(prev_cpu);
> this_eff_load *= this_load +
> effective_load(tg, this_cpu, weight, weight);
>
> prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
> - prev_eff_load *= power_of(this_cpu);
> + prev_eff_load *= capacity_of(this_cpu);
> prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
>
> balanced = this_eff_load <= prev_eff_load;
> @@ -4919,14 +4919,14 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp
> *
> * W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0 (3)
> *
> - * P_i is the cpu power (or compute capacity) of cpu i, typically it is the
> + * C_i is the compute capacity of cpu i, typically it is the
> * fraction of 'recent' time available for SCHED_OTHER task execution. But it
> * can also include other factors [XXX].
> *
> * To achieve this balance we define a measure of imbalance which follows
> * directly from (1):
> *
> - * imb_i,j = max{ avg(W/P), W_i/P_i } - min{ avg(W/P), W_j/P_j } (4)
> + * imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j } (4)
> *
> * We them move tasks around to minimize the imbalance. In the continuous
> * function space it is obvious this converges, in the discrete case we get
> @@ -5560,17 +5560,17 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
> return load_idx;
> }
>
> -static unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
> +static unsigned long default_scale_capacity(struct sched_domain *sd, int cpu)
> {
> return SCHED_POWER_SCALE;
> }
>
> unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
> {
> - return default_scale_freq_power(sd, cpu);
> + return default_scale_capacity(sd, cpu);
> }
>
> -static unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
> +static unsigned long default_scale_smt_capacity(struct sched_domain *sd, int cpu)
> {
> unsigned long weight = sd->span_weight;
> unsigned long smt_gain = sd->smt_gain;
> @@ -5582,10 +5582,10 @@ static unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
>
> unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
> {
> - return default_scale_smt_power(sd, cpu);
> + return default_scale_smt_capacity(sd, cpu);
> }
>
> -static unsigned long scale_rt_power(int cpu)
> +static unsigned long scale_rt_capacity(int cpu)
> {
> struct rq *rq = cpu_rq(cpu);
> u64 total, available, age_stamp, avg;
> @@ -5605,7 +5605,7 @@ static unsigned long scale_rt_power(int cpu)
> total = sched_avg_period() + delta;
>
> if (unlikely(total < avg)) {
> - /* Ensures that power won't end up being negative */
> + /* Ensures that capacity won't end up being negative */
> available = 0;
> } else {
> available = total - avg;
> @@ -5619,38 +5619,38 @@ static unsigned long scale_rt_power(int cpu)
> return div_u64(available, total);
> }
>
> -static void update_cpu_power(struct sched_domain *sd, int cpu)
> +static void update_cpu_capacity(struct sched_domain *sd, int cpu)
> {
> unsigned long weight = sd->span_weight;
> - unsigned long power = SCHED_POWER_SCALE;
> + unsigned long capacity = SCHED_POWER_SCALE;
> struct sched_group *sdg = sd->groups;
>
> if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
> if (sched_feat(ARCH_POWER))
> - power *= arch_scale_smt_power(sd, cpu);
> + capacity *= arch_scale_smt_power(sd, cpu);
> else
> - power *= default_scale_smt_power(sd, cpu);
> + capacity *= default_scale_smt_capacity(sd, cpu);
>
> - power >>= SCHED_POWER_SHIFT;
> + capacity >>= SCHED_POWER_SHIFT;
> }
>
> - sdg->sgc->capacity_orig = power;
> + sdg->sgc->capacity_orig = capacity;
>
> if (sched_feat(ARCH_POWER))
> - power *= arch_scale_freq_power(sd, cpu);
> + capacity *= arch_scale_freq_power(sd, cpu);
> else
> - power *= default_scale_freq_power(sd, cpu);
> + capacity *= default_scale_capacity(sd, cpu);
>
> - power >>= SCHED_POWER_SHIFT;
> + capacity >>= SCHED_POWER_SHIFT;
>
> - power *= scale_rt_power(cpu);
> - power >>= SCHED_POWER_SHIFT;
> + capacity *= scale_rt_capacity(cpu);
> + capacity >>= SCHED_POWER_SHIFT;
>
> - if (!power)
> - power = 1;
> + if (!capacity)
> + capacity = 1;
>
> - cpu_rq(cpu)->cpu_power = power;
> - sdg->sgc->capacity = power;
> + cpu_rq(cpu)->cpu_capacity = capacity;
> + sdg->sgc->capacity = capacity;
> }
>
> void update_group_capacity(struct sched_domain *sd, int cpu)
> @@ -5665,7 +5665,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
> sdg->sgc->next_update = jiffies + interval;
>
> if (!child) {
> - update_cpu_power(sd, cpu);
> + update_cpu_capacity(sd, cpu);
> return;
> }
>
> @@ -5686,8 +5686,8 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
> * gets here before we've attached the domains to the
> * runqueues.
> *
> - * Use power_of(), which is set irrespective of domains
> - * in update_cpu_power().
> + * Use capacity_of(), which is set irrespective of domains
> + * in update_cpu_capacity().
> *
> * This avoids capacity/capacity_orig from being 0 and
> * causing divide-by-zero issues on boot.
> @@ -5695,8 +5695,8 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
> * Runtime updates will correct capacity_orig.
> */
> if (unlikely(!rq->sd)) {
> - capacity_orig += power_of(cpu);
> - capacity += power_of(cpu);
> + capacity_orig += capacity_of(cpu);
> + capacity += capacity_of(cpu);
> continue;
> }
>
> @@ -5784,7 +5784,7 @@ static inline int sg_imbalanced(struct sched_group *group)
> /*
> * Compute the group capacity factor.
> *
> - * Avoid the issue where N*frac(smt_power) >= 1 creates 'phantom' cores by
> + * Avoid the issue where N*frac(smt_capacity) >= 1 creates 'phantom' cores by
> * first dividing out the smt factor and computing the actual number of cores
> * and limit unit capacity with that.
> */
> @@ -6082,7 +6082,7 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds)
>
> /*
> * OK, we don't have enough imbalance to justify moving tasks,
> - * however we may be able to increase total CPU power used by
> + * however we may be able to increase total CPU capacity used by
> * moving them.
> */
>
> @@ -6143,7 +6143,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
> /*
> * In the presence of smp nice balancing, certain scenarios can have
> * max load less than avg load(as we skip the groups at or below
> - * its cpu_power, while calculating max_load..)
> + * its cpu_capacity, while calculating max_load..)
> */
> if (busiest->avg_load <= sds->avg_load ||
> local->avg_load >= sds->avg_load) {
> @@ -6298,11 +6298,11 @@ static struct rq *find_busiest_queue(struct lb_env *env,
> struct sched_group *group)
> {
> struct rq *busiest = NULL, *rq;
> - unsigned long busiest_load = 0, busiest_power = 1;
> + unsigned long busiest_load = 0, busiest_capacity = 1;
> int i;
>
> for_each_cpu_and(i, sched_group_cpus(group), env->cpus) {
> - unsigned long power, capa_factor, wl;
> + unsigned long capacity, capa_factor, wl;
> enum fbq_type rt;
>
> rq = cpu_rq(i);
> @@ -6330,8 +6330,8 @@ static struct rq *find_busiest_queue(struct lb_env *env,
> if (rt > env->fbq_type)
> continue;
>
> - power = power_of(i);
> - capa_factor = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
> + capacity = capacity_of(i);
> + capa_factor = DIV_ROUND_CLOSEST(capacity, SCHED_POWER_SCALE);
> if (!capa_factor)
> capa_factor = fix_small_capacity(env->sd, group);
>
> @@ -6339,25 +6339,25 @@ static struct rq *find_busiest_queue(struct lb_env *env,
>
> /*
> * When comparing with imbalance, use weighted_cpuload()
> - * which is not scaled with the cpu power.
> + * which is not scaled with the cpu capacity.
> */
> if (capa_factor && rq->nr_running == 1 && wl > env->imbalance)
> continue;
>
> /*
> * For the load comparisons with the other cpu's, consider
> - * the weighted_cpuload() scaled with the cpu power, so that
> - * the load can be moved away from the cpu that is potentially
> - * running at a lower capacity.
> + * the weighted_cpuload() scaled with the cpu capacity, so
> + * that the load can be moved away from the cpu that is
> + * potentially running at a lower capacity.
> *
> - * Thus we're looking for max(wl_i / power_i), crosswise
> + * Thus we're looking for max(wl_i / capacity_i), crosswise
> * multiplication to rid ourselves of the division works out
> - * to: wl_i * power_j > wl_j * power_i; where j is our
> - * previous maximum.
> + * to: wl_i * capacity_j > wl_j * capacity_i; where j is
> + * our previous maximum.
> */
> - if (wl * busiest_power > busiest_load * power) {
> + if (wl * busiest_capacity > busiest_load * capacity) {
> busiest_load = wl;
> - busiest_power = power;
> + busiest_capacity = capacity;
> busiest = rq;
> }
> }
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index b384ccd07b..fe89387931 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -567,7 +567,7 @@ struct rq {
> struct root_domain *rd;
> struct sched_domain *sd;
>
> - unsigned long cpu_power;
> + unsigned long cpu_capacity;
>
> unsigned char idle_balance;
> /* For active balancing */
> --
> 1.8.4.108.g55ea5f6
>
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