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sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c

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Move effective_cpu_util() and sched_cpu_util() functions in fair.c file
with others utilization related functions.

No functional change.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20240904092417.20660-1-vincent.guittot@linaro.org
This commit is contained in:
Vincent Guittot 2024-09-04 11:24:17 +02:00 committed by Peter Zijlstra
parent 3dcac251b0
commit 5d871a6399
2 changed files with 99 additions and 101 deletions
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99
kernel/sched/fair.c
View File

@ -8084,6 +8084,105 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p)
return cpu_util(cpu, p, -1, 0);
}
/*
* This function computes an effective utilization for the given CPU, to be
* used for frequency selection given the linear relation: f = u * f_max.
*
* The scheduler tracks the following metrics:
*
* cpu_util_{cfs,rt,dl,irq}()
* cpu_bw_dl()
*
* Where the cfs,rt and dl util numbers are tracked with the same metric and
* synchronized windows and are thus directly comparable.
*
* The cfs,rt,dl utilization are the running times measured with rq->clock_task
* which excludes things like IRQ and steal-time. These latter are then accrued
* in the IRQ utilization.
*
* The DL bandwidth number OTOH is not a measured metric but a value computed
* based on the task model parameters and gives the minimal utilization
* required to meet deadlines.
*/
unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
unsigned long *min,
unsigned long *max)
{
unsigned long util, irq, scale;
struct rq *rq = cpu_rq(cpu);
scale = arch_scale_cpu_capacity(cpu);
/*
* Early check to see if IRQ/steal time saturates the CPU, can be
* because of inaccuracies in how we track these -- see
* update_irq_load_avg().
*/
irq = cpu_util_irq(rq);
if (unlikely(irq >= scale)) {
if (min)
*min = scale;
if (max)
*max = scale;
return scale;
}
if (min) {
/*
* The minimum utilization returns the highest level between:
* - the computed DL bandwidth needed with the IRQ pressure which
* steals time to the deadline task.
* - The minimum performance requirement for CFS and/or RT.
*/
*min = max(irq + cpu_bw_dl(rq), uclamp_rq_get(rq, UCLAMP_MIN));
/*
* When an RT task is runnable and uclamp is not used, we must
* ensure that the task will run at maximum compute capacity.
*/
if (!uclamp_is_used() && rt_rq_is_runnable(&rq->rt))
*min = max(*min, scale);
}
/*
* Because the time spend on RT/DL tasks is visible as 'lost' time to
* CFS tasks and we use the same metric to track the effective
* utilization (PELT windows are synchronized) we can directly add them
* to obtain the CPU's actual utilization.
*/
util = util_cfs + cpu_util_rt(rq);
util += cpu_util_dl(rq);
/*
* The maximum hint is a soft bandwidth requirement, which can be lower
* than the actual utilization because of uclamp_max requirements.
*/
if (max)
*max = min(scale, uclamp_rq_get(rq, UCLAMP_MAX));
if (util >= scale)
return scale;
/*
* There is still idle time; further improve the number by using the
* IRQ metric. Because IRQ/steal time is hidden from the task clock we
* need to scale the task numbers:
*
* max - irq
* U' = irq + --------- * U
* max
*/
util = scale_irq_capacity(util, irq, scale);
util += irq;
return min(scale, util);
}
unsigned long sched_cpu_util(int cpu)
{
return effective_cpu_util(cpu, cpu_util_cfs(cpu), NULL, NULL);
}
/*
* energy_env - Utilization landscape for energy estimation.
* @task_busy_time: Utilization contribution by the task for which we test the

101
kernel/sched/syscalls.c
View File

@ -258,107 +258,6 @@ int sched_core_idle_cpu(int cpu)
#endif
#ifdef CONFIG_SMP
/*
* This function computes an effective utilization for the given CPU, to be
* used for frequency selection given the linear relation: f = u * f_max.
*
* The scheduler tracks the following metrics:
*
* cpu_util_{cfs,rt,dl,irq}()
* cpu_bw_dl()
*
* Where the cfs,rt and dl util numbers are tracked with the same metric and
* synchronized windows and are thus directly comparable.
*
* The cfs,rt,dl utilization are the running times measured with rq->clock_task
* which excludes things like IRQ and steal-time. These latter are then accrued
* in the IRQ utilization.
*
* The DL bandwidth number OTOH is not a measured metric but a value computed
* based on the task model parameters and gives the minimal utilization
* required to meet deadlines.
*/
unsigned long effective_cpu_util(int cpu, unsigned long util_cfs,
unsigned long *min,
unsigned long *max)
{
unsigned long util, irq, scale;
struct rq *rq = cpu_rq(cpu);
scale = arch_scale_cpu_capacity(cpu);
/*
* Early check to see if IRQ/steal time saturates the CPU, can be
* because of inaccuracies in how we track these -- see
* update_irq_load_avg().
*/
irq = cpu_util_irq(rq);
if (unlikely(irq >= scale)) {
if (min)
*min = scale;
if (max)
*max = scale;
return scale;
}
if (min) {
/*
* The minimum utilization returns the highest level between:
* - the computed DL bandwidth needed with the IRQ pressure which
* steals time to the deadline task.
* - The minimum performance requirement for CFS and/or RT.
*/
*min = max(irq + cpu_bw_dl(rq), uclamp_rq_get(rq, UCLAMP_MIN));
/*
* When an RT task is runnable and uclamp is not used, we must
* ensure that the task will run at maximum compute capacity.
*/
if (!uclamp_is_used() && rt_rq_is_runnable(&rq->rt))
*min = max(*min, scale);
}
/*
* Because the time spend on RT/DL tasks is visible as 'lost' time to
* CFS tasks and we use the same metric to track the effective
* utilization (PELT windows are synchronized) we can directly add them
* to obtain the CPU's actual utilization.
*/
util = util_cfs + cpu_util_rt(rq);
util += cpu_util_dl(rq);
/*
* The maximum hint is a soft bandwidth requirement, which can be lower
* than the actual utilization because of uclamp_max requirements.
*/
if (max)
*max = min(scale, uclamp_rq_get(rq, UCLAMP_MAX));
if (util >= scale)
return scale;
/*
* There is still idle time; further improve the number by using the
* IRQ metric. Because IRQ/steal time is hidden from the task clock we
* need to scale the task numbers:
*
* max - irq
* U' = irq + --------- * U
* max
*/
util = scale_irq_capacity(util, irq, scale);
util += irq;
return min(scale, util);
}
unsigned long sched_cpu_util(int cpu)
{
return effective_cpu_util(cpu, cpu_util_cfs(cpu), NULL, NULL);
}
#endif /* CONFIG_SMP */
/**
* find_process_by_pid - find a process with a matching PID value.
* @pid: the pid in question.