Commit-ID: 07881166a892fa4908ac4924660a7793f75d6544
Gitweb: https://git.kernel.org/tip/07881166a892fa4908ac4924660a7793f75d6544
Author: Juri Lelli <juri.lelli@xxxxxxx>
AuthorDate: Mon, 4 Dec 2017 11:23:25 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 10 Jan 2018 12:53:35 +0100
sched/deadline: Make bandwidth enforcement scale-invariant
Apply frequency and CPU scale-invariance correction factor to bandwidth
enforcement (similar to what we already do to fair utilization tracking).
Each delta_exec gets scaled considering current frequency and maximum
CPU capacity; which means that the reservation runtime parameter (that
need to be specified profiling the task execution at max frequency on
biggest capacity core) gets thus scaled accordingly.
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Claudio Scordino <claudio@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Luca Abeni <luca.abeni@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rafael J . Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: alessio.balsini@xxxxxxx
Cc: bristot@xxxxxxxxxx
Cc: dietmar.eggemann@xxxxxxx
Cc: joelaf@xxxxxxxxxx
Cc: juri.lelli@xxxxxxxxxx
Cc: mathieu.poirier@xxxxxxxxxx
Cc: morten.rasmussen@xxxxxxx
Cc: patrick.bellasi@xxxxxxx
Cc: rjw@xxxxxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: tkjos@xxxxxxxxxxx
Cc: tommaso.cucinotta@xxxxxxxxxxxxxxx
Cc: vincent.guittot@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20171204102325.5110-9-juri.lelli@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/deadline.c | 26 ++++++++++++++++++++++----
kernel/sched/fair.c | 2 --
kernel/sched/sched.h | 2 ++
3 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 54a0dc1..9bb0e0c 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1151,7 +1151,8 @@ static void update_curr_dl(struct rq *rq)
{
struct task_struct *curr = rq->curr;
struct sched_dl_entity *dl_se = &curr->dl;
- u64 delta_exec;
+ u64 delta_exec, scaled_delta_exec;
+ int cpu = cpu_of(rq);
if (!dl_task(curr) || !on_dl_rq(dl_se))
return;
@@ -1185,9 +1186,26 @@ static void update_curr_dl(struct rq *rq)
if (dl_entity_is_special(dl_se))
return;
- if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM))
- delta_exec = grub_reclaim(delta_exec, rq, &curr->dl);
- dl_se->runtime -= delta_exec;
+ /*
+ * For tasks that participate in GRUB, we implement GRUB-PA: the
+ * spare reclaimed bandwidth is used to clock down frequency.
+ *
+ * For the others, we still need to scale reservation parameters
+ * according to current frequency and CPU maximum capacity.
+ */
+ if (unlikely(dl_se->flags & SCHED_FLAG_RECLAIM)) {
+ scaled_delta_exec = grub_reclaim(delta_exec,
+ rq,
+ &curr->dl);
+ } else {
+ unsigned long scale_freq = arch_scale_freq_capacity(cpu);
+ unsigned long scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
+
+ scaled_delta_exec = cap_scale(delta_exec, scale_freq);
+ scaled_delta_exec = cap_scale(scaled_delta_exec, scale_cpu);
+ }
+
+ dl_se->runtime -= scaled_delta_exec;
throttle:
if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1485975..1070803 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3089,8 +3089,6 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
return c1 + c2 + c3;
}
-#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
-
/*
* Accumulate the three separate parts of the sum; d1 the remainder
* of the last (incomplete) period, d2 the span of full periods and d3
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e122c89..2e95505 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -156,6 +156,8 @@ static inline int task_has_dl_policy(struct task_struct *p)
return dl_policy(p->policy);
}
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
/*
* !! For sched_setattr_nocheck() (kernel) only !!
*
--
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