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Message-Id: <20240904092417.20660-1-vincent.guittot@linaro.org>
Date: Wed, 4 Sep 2024 11:24:17 +0200
From: Vincent Guittot <vincent.guittot@...aro.org>
To: mingo@...hat.com,
peterz@...radead.org,
juri.lelli@...hat.com,
dietmar.eggemann@....com,
rostedt@...dmis.org,
bsegall@...gle.com,
mgorman@...e.de,
vschneid@...hat.com,
linux-kernel@...r.kernel.org
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH] sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
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@...aro.org>
---
kernel/sched/fair.c | 99 +++++++++++++++++++++++++++++++++++++++
kernel/sched/syscalls.c | 101 ----------------------------------------
2 files changed, 99 insertions(+), 101 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d697a0a3fc73..9e19009da48f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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
diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c
index 4fae3cf25a3a..c62acf509b74 100644
--- a/kernel/sched/syscalls.c
+++ b/kernel/sched/syscalls.c
@@ -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.
--
2.34.1
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