| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <06412759-659c-4b80-b946-f533775baa02@arm.com>
Date: Fri, 15 Dec 2023 16:03:28 +0000
From: Lukasz Luba <lukasz.luba@....com>
To: Vincent Guittot <vincent.guittot@...aro.org>
Cc: catalin.marinas@....com, will@...nel.org,
linux-trace-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
mgorman@...e.de, linux-pm@...r.kernel.org, amit.kachhap@...il.com,
daniel.lezcano@...aro.org, mhiramat@...nel.org, vschneid@...hat.com,
bristot@...hat.com, dietmar.eggemann@....com, juri.lelli@...hat.com,
agross@...nel.org, peterz@...radead.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, konrad.dybcio@...aro.org,
andersson@...nel.org, viresh.kumar@...aro.org, sudeep.holla@....com,
rafael@...nel.org, mingo@...hat.com, rostedt@...dmis.org,
bsegall@...gle.com, rui.zhang@...el.com
Subject: Re: [PATCH 2/4] sched: Take cpufreq feedback into account
On 12/12/23 14:27, Vincent Guittot wrote:
> Aggregate the different pressures applied on the capacity of CPUs and
> create a new function that returns the actual capacity of the CPU:
> get_actual_cpu_capacity()
>
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
> ---
> kernel/sched/fair.c | 43 +++++++++++++++++++++++--------------------
> 1 file changed, 23 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index bcea3d55d95d..11d3be829302 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4932,12 +4932,20 @@ static inline void util_est_update(struct cfs_rq *cfs_rq,
> trace_sched_util_est_se_tp(&p->se);
> }
>
> +static inline unsigned long get_actual_cpu_capacity(int cpu)
> +{
> + unsigned long capacity = arch_scale_cpu_capacity(cpu);
> +
> + capacity -= max(thermal_load_avg(cpu_rq(cpu)), cpufreq_get_pressure(cpu));
> +
> + return capacity;
> +}
> static inline int util_fits_cpu(unsigned long util,
> unsigned long uclamp_min,
> unsigned long uclamp_max,
> int cpu)
> {
> - unsigned long capacity_orig, capacity_orig_thermal;
> + unsigned long capacity_orig;
> unsigned long capacity = capacity_of(cpu);
> bool fits, uclamp_max_fits;
>
> @@ -4970,7 +4978,6 @@ static inline int util_fits_cpu(unsigned long util,
> * goal is to cap the task. So it's okay if it's getting less.
> */
> capacity_orig = arch_scale_cpu_capacity(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.
> @@ -5045,7 +5052,7 @@ static inline int util_fits_cpu(unsigned long util,
> * handle the case uclamp_min > uclamp_max.
> */
> uclamp_min = min(uclamp_min, uclamp_max);
> - if (fits && (util < uclamp_min) && (uclamp_min > capacity_orig_thermal))
> + if (fits && (util < uclamp_min) && (uclamp_min > get_actual_cpu_capacity(cpu)))
That's quite long line, I would break it into 2.
> return -1;
>
> return fits;
> @@ -7426,7 +7433,7 @@ select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)
> * Look for the CPU with best capacity.
> */
> else if (fits < 0)
> - cpu_cap = arch_scale_cpu_capacity(cpu) - thermal_load_avg(cpu_rq(cpu));
> + cpu_cap = get_actual_cpu_capacity(cpu);
>
> /*
> * First, select CPU which fits better (-1 being better than 0).
> @@ -7919,8 +7926,8 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
> struct root_domain *rd = this_rq()->rd;
> int cpu, best_energy_cpu, target = -1;
> int prev_fits = -1, best_fits = -1;
> - unsigned long best_thermal_cap = 0;
> - unsigned long prev_thermal_cap = 0;
> + unsigned long best_actual_cap = 0;
> + unsigned long prev_actual_cap = 0;
> struct sched_domain *sd;
> struct perf_domain *pd;
> struct energy_env eenv;
> @@ -7950,7 +7957,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
>
> for (; pd; pd = pd->next) {
> unsigned long util_min = p_util_min, util_max = p_util_max;
> - unsigned long cpu_cap, cpu_thermal_cap, util;
> + unsigned long cpu_cap, cpu_actual_cap, util;
> long prev_spare_cap = -1, max_spare_cap = -1;
> unsigned long rq_util_min, rq_util_max;
> unsigned long cur_delta, base_energy;
> @@ -7962,18 +7969,17 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
> if (cpumask_empty(cpus))
> continue;
>
> - /* Account thermal pressure for the energy estimation */
> + /* Account external pressure for the energy estimation */
> cpu = cpumask_first(cpus);
> - cpu_thermal_cap = arch_scale_cpu_capacity(cpu);
> - cpu_thermal_cap -= arch_scale_thermal_pressure(cpu);
> + cpu_actual_cap = get_actual_cpu_capacity(cpu);
>
> - eenv.cpu_cap = cpu_thermal_cap;
> + eenv.cpu_cap = cpu_actual_cap;
> eenv.pd_cap = 0;
>
> for_each_cpu(cpu, cpus) {
> struct rq *rq = cpu_rq(cpu);
>
> - eenv.pd_cap += cpu_thermal_cap;
> + eenv.pd_cap += cpu_actual_cap;
>
> if (!cpumask_test_cpu(cpu, sched_domain_span(sd)))
> continue;
> @@ -8044,7 +8050,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
> if (prev_delta < base_energy)
> goto unlock;
> prev_delta -= base_energy;
> - prev_thermal_cap = cpu_thermal_cap;
> + prev_actual_cap = cpu_actual_cap;
> best_delta = min(best_delta, prev_delta);
> }
>
> @@ -8059,7 +8065,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
> * but best energy cpu has better capacity.
> */
> if ((max_fits < 0) &&
> - (cpu_thermal_cap <= best_thermal_cap))
> + (cpu_actual_cap <= best_actual_cap))
> continue;
>
> cur_delta = compute_energy(&eenv, pd, cpus, p,
> @@ -8080,14 +8086,14 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
> best_delta = cur_delta;
> best_energy_cpu = max_spare_cap_cpu;
> best_fits = max_fits;
> - best_thermal_cap = cpu_thermal_cap;
> + best_actual_cap = cpu_actual_cap;
> }
> }
> rcu_read_unlock();
>
> if ((best_fits > prev_fits) ||
> ((best_fits > 0) && (best_delta < prev_delta)) ||
> - ((best_fits < 0) && (best_thermal_cap > prev_thermal_cap)))
> + ((best_fits < 0) && (best_actual_cap > prev_actual_cap)))
> target = best_energy_cpu;
>
> return target;
> @@ -9466,7 +9472,7 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
> static unsigned long scale_rt_capacity(int cpu)
> {
> struct rq *rq = cpu_rq(cpu);
> - unsigned long max = arch_scale_cpu_capacity(cpu);
> + unsigned long max = get_actual_cpu_capacity(cpu);
Maybe it's not strictly related to this patch, but I would swap the
2 above lines, so that they will be sorted (from longest to shortest).
> unsigned long used, free;
> unsigned long irq;
>
> @@ -9478,12 +9484,9 @@ static unsigned long scale_rt_capacity(int cpu)
> /*
> * avg_rt.util_avg and avg_dl.util_avg track binary signals
> * (running and not running) with weights 0 and 1024 respectively.
> - * avg_thermal.load_avg tracks thermal pressure and the weighted
> - * average uses the actual delta max capacity(load).
> */
> used = READ_ONCE(rq->avg_rt.util_avg);
> used += READ_ONCE(rq->avg_dl.util_avg);
> - used += thermal_load_avg(rq);
>
> if (unlikely(used >= max))
> return 1;
The rest looks good
Reviewed-by: Lukasz Luba <lukasz.luba@....com>
Powered by blists - more mailing lists