From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Xuewen Yan <xuewen.yan@unisoc.com>, lukasz.luba@arm.com
Cc: rafael@kernel.org, viresh.kumar@linaro.org, mingo@redhat.com,
peterz@infradead.org, vincent.guittot@linaro.org,
rostedt@goodmis.org, linux-kernel@vger.kernel.org,
di.shen@unisoc.com, xuewen.yan94@gmail.com
Subject: Re: [PATCH] sched: Take thermal pressure into account when determine rt fits capacity
Date: Mon, 11 Apr 2022 10:21:22 +0200 [thread overview]
Message-ID: <02350916-aa36-ea53-2c98-91b97f49d27e@arm.com> (raw)
In-Reply-To: <20220407051932.4071-1-xuewen.yan@unisoc.com>
On 07/04/2022 07:19, Xuewen Yan wrote:
> There are cases when the cpu max capacity might be reduced due to thermal.
> Take into the thermal pressure into account when judge whether the rt task
> fits the cpu. And when schedutil govnor get cpu util, the thermal pressure
> also should be considered.
>
> Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
> ---
> kernel/sched/cpufreq_schedutil.c | 1 +
> kernel/sched/rt.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 3dbf351d12d5..285ad51caf0f 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -159,6 +159,7 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu)
> struct rq *rq = cpu_rq(sg_cpu->cpu);
> unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
>
> + max -= arch_scale_thermal_pressure(sg_cpu->cpu);
max' = arch_scale_cpu_capacity() - arch_scale_thermal_pressure()
For the energy part (A) we use max' in compute_energy() to cap sum_util
and max_util at max' and to call em_cpu_energy(..., max_util, sum_util,
max'). This was done to match (B)'s `policy->max` capping.
For the frequency part (B) we have freq_qos_update_request() in:
power_actor_set_power()
...
cdev->ops->set_cur_state()
cpufreq_set_cur_state()
freq_qos_update_request() <-- !
arch_update_thermal_pressure()
restricting `policy->max` which then clamps `target_freq` in:
cpufreq_update_util()
...
get_next_freq()
cpufreq_driver_resolve_freq()
__resolve_freq()
[...]
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index a32c46889af8..d9982ebd4821 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -466,6 +466,7 @@ static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
> max_cap = uclamp_eff_value(p, UCLAMP_MAX);
>
> cpu_cap = capacity_orig_of(cpu);
> + cpu_cap -= arch_scale_thermal_pressure(cpu);
>
> return cpu_cap >= min(min_cap, max_cap);
> }
IMHO, this should follow what we do with rq->cpu_capacity
(capacity_of(), the remaining capacity for CFS). E.g. we use
capacity_of() in find_energy_efficient_cpu() and select_idle_capacity()
to compare capacities. So we would need a function like
scale_rt_capacity() for RT (minus the rq->avg_rt.util_avg) but then also
one for DL (minus rq->avg_dl.util_avg and rq->avg_rt.util_avg).
next prev parent reply other threads:[~2022-04-11 8:21 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 5:19 [PATCH] sched: Take thermal pressure into account when determine rt fits capacity Xuewen Yan
2022-04-11 8:21 ` Dietmar Eggemann [this message]
2022-04-11 8:52 ` Xuewen Yan
2022-04-11 14:07 ` Dietmar Eggemann
2022-04-13 13:25 ` Lukasz Luba
2022-04-16 2:47 ` Xuewen Yan
2022-04-19 7:14 ` Vincent Guittot
2022-04-19 12:01 ` Lukasz Luba
2022-04-19 12:51 ` Vincent Guittot
2022-04-19 14:13 ` Lukasz Luba
2022-04-21 8:29 ` Vincent Guittot
2022-04-21 10:57 ` Lukasz Luba
2022-04-26 7:39 ` Vincent Guittot
2022-04-29 9:27 ` Lukasz Luba
2022-04-20 13:51 ` Qais Yousef
2022-04-21 8:07 ` Xuewen Yan
2022-04-21 16:15 ` Qais Yousef
2022-04-25 1:31 ` Xuewen Yan
2022-04-25 16:12 ` Qais Yousef
2022-04-26 2:07 ` Xuewen Yan
2022-04-26 8:09 ` Vincent Guittot
2022-04-26 9:30 ` Qais Yousef
2022-04-26 10:06 ` Vincent Guittot
2022-04-26 13:06 ` Qais Yousef
2022-04-26 9:21 ` Qais Yousef
2022-04-27 1:38 ` Xuewen Yan
2022-04-27 10:58 ` Qais Yousef
2022-05-01 3:20 ` Xuewen Yan
2022-05-03 14:43 ` Qais Yousef
2022-05-09 2:29 ` Xuewen Yan
2022-05-10 14:56 ` Qais Yousef
2022-05-10 17:44 ` Lukasz Luba
2022-05-10 18:44 ` Qais Yousef
2022-05-10 22:03 ` Lukasz Luba
2022-05-14 15:01 ` Xuewen Yan
2022-05-14 23:55 ` Qais Yousef
2022-05-15 0:53 ` [PATCH] sched/rt: Support multi-criterion fitness search for kernel test robot
2022-05-15 1:43 ` kernel test robot
2022-05-19 14:16 ` [sched] 0eee64011b: canonical_address#:#[##] kernel test robot
2022-06-15 10:13 ` [PATCH] sched: Take thermal pressure into account when determine rt fits capacity Qais Yousef
2022-06-15 11:17 ` Xuewen Yan
2022-06-15 13:54 ` Qais Yousef
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