[tip: sched/core] sched/eevdf: More PELT vs DELAYED_DEQUEUE

From: tip-bot2 for Peter Zijlstra
Date: Mon Dec 09 2024 - 06:02:12 EST

Next message: tip-bot2 for K Prateek Nayak: "[tip: sched/core] sched/fair: Fix NEXT_BUDDY"
Previous message: tip-bot2 for Vincent Guittot: " [tip: sched/core] sched/fair: Fix sched_can_stop_tick() for fair tasks"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

The following commit has been merged into the sched/core branch of tip:

Commit-ID: 76f2f783294d7d55c2564e2dfb0a7279ba0bc264
Gitweb: https://git.kernel.org/tip/76f2f783294d7d55c2564e2dfb0a7279ba0bc264
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 02 Dec 2024 18:45:57 +01:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 09 Dec 2024 11:48:09 +01:00

sched/eevdf: More PELT vs DELAYED_DEQUEUE

Vincent and Dietmar noted that while
commit fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE") fixes
the entity runnable stats, it does not adjust the cfs_rq runnable stats,
which are based off of h_nr_running.

Track h_nr_delayed such that we can discount those and adjust the
signal.

Fixes: fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE")
Closes: https://lore.kernel.org/lkml/a9a45193-d0c6-4ba2-a822-464ad30b550e@xxxxxxx/
Closes: https://lore.kernel.org/lkml/CAKfTPtCNUvWE_GX5LyvTF-WdxUT=ZgvZZv-4t=eWntg5uOFqiQ@xxxxxxxxxxxxxx/
[ Fixes checkpatch warnings and rebased ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reported-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Reported-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Tested-by: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Link: https://lore.kernel.org/r/20241202174606.4074512-3-vincent.guittot@xxxxxxxxxx
---
kernel/sched/debug.c | 1 +-
kernel/sched/fair.c | 51 ++++++++++++++++++++++++++++++++++++++-----
kernel/sched/pelt.c | 2 +-
kernel/sched/sched.h | 8 +++++--
4 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index a48b2a7..a1be00a 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -845,6 +845,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
SEQ_printf(m, " .%-30s: %Ld.%06ld\n", "spread", SPLIT_NS(spread));
SEQ_printf(m, " .%-30s: %d\n", "nr_running", cfs_rq->nr_running);
SEQ_printf(m, " .%-30s: %d\n", "h_nr_running", cfs_rq->h_nr_running);
+ SEQ_printf(m, " .%-30s: %d\n", "h_nr_delayed", cfs_rq->h_nr_delayed);
SEQ_printf(m, " .%-30s: %d\n", "idle_nr_running",
cfs_rq->idle_nr_running);
SEQ_printf(m, " .%-30s: %d\n", "idle_h_nr_running",
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9d7a2dd..97ee48c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5465,9 +5465,33 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)

static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);

-static inline void finish_delayed_dequeue_entity(struct sched_entity *se)
+static void set_delayed(struct sched_entity *se)
+{
+ se->sched_delayed = 1;
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ cfs_rq->h_nr_delayed++;
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+ }
+}
+
+static void clear_delayed(struct sched_entity *se)
{
se->sched_delayed = 0;
+ for_each_sched_entity(se) {
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ cfs_rq->h_nr_delayed--;
+ if (cfs_rq_throttled(cfs_rq))
+ break;
+ }
+}
+
+static inline void finish_delayed_dequeue_entity(struct sched_entity *se)
+{
+ clear_delayed(se);
if (sched_feat(DELAY_ZERO) && se->vlag > 0)
se->vlag = 0;
}
@@ -5496,7 +5520,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
if (sched_feat(DELAY_DEQUEUE) && delay &&
!entity_eligible(cfs_rq, se)) {
update_load_avg(cfs_rq, se, 0);
- se->sched_delayed = 1;
+ set_delayed(se);
return false;
}
}
@@ -5908,7 +5932,7 @@ static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)
struct rq *rq = rq_of(cfs_rq);
struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
struct sched_entity *se;
- long task_delta, idle_task_delta, dequeue = 1;
+ long task_delta, idle_task_delta, delayed_delta, dequeue = 1;
long rq_h_nr_running = rq->cfs.h_nr_running;

raw_spin_lock(&cfs_b->lock);
@@ -5941,6 +5965,7 @@ static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)

task_delta = cfs_rq->h_nr_running;
idle_task_delta = cfs_rq->idle_h_nr_running;
+ delayed_delta = cfs_rq->h_nr_delayed;
for_each_sched_entity(se) {
struct cfs_rq *qcfs_rq = cfs_rq_of(se);
int flags;
@@ -5964,6 +5989,7 @@ static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)

qcfs_rq->h_nr_running -= task_delta;
qcfs_rq->idle_h_nr_running -= idle_task_delta;
+ qcfs_rq->h_nr_delayed -= delayed_delta;

if (qcfs_rq->load.weight) {
/* Avoid re-evaluating load for this entity: */
@@ -5986,6 +6012,7 @@ static bool throttle_cfs_rq(struct cfs_rq *cfs_rq)

qcfs_rq->h_nr_running -= task_delta;
qcfs_rq->idle_h_nr_running -= idle_task_delta;
+ qcfs_rq->h_nr_delayed -= delayed_delta;
}

/* At this point se is NULL and we are at root level*/
@@ -6011,7 +6038,7 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
struct rq *rq = rq_of(cfs_rq);
struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
struct sched_entity *se;
- long task_delta, idle_task_delta;
+ long task_delta, idle_task_delta, delayed_delta;
long rq_h_nr_running = rq->cfs.h_nr_running;

se = cfs_rq->tg->se[cpu_of(rq)];
@@ -6047,6 +6074,7 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)

task_delta = cfs_rq->h_nr_running;
idle_task_delta = cfs_rq->idle_h_nr_running;
+ delayed_delta = cfs_rq->h_nr_delayed;
for_each_sched_entity(se) {
struct cfs_rq *qcfs_rq = cfs_rq_of(se);

@@ -6064,6 +6092,7 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)

qcfs_rq->h_nr_running += task_delta;
qcfs_rq->idle_h_nr_running += idle_task_delta;
+ qcfs_rq->h_nr_delayed += delayed_delta;

/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(qcfs_rq))
@@ -6081,6 +6110,7 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)

qcfs_rq->h_nr_running += task_delta;
qcfs_rq->idle_h_nr_running += idle_task_delta;
+ qcfs_rq->h_nr_delayed += delayed_delta;

/* end evaluation on encountering a throttled cfs_rq */
if (cfs_rq_throttled(qcfs_rq))
@@ -6934,7 +6964,7 @@ requeue_delayed_entity(struct sched_entity *se)
}

update_load_avg(cfs_rq, se, 0);
- se->sched_delayed = 0;
+ clear_delayed(se);
}

/*
@@ -6948,6 +6978,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
int idle_h_nr_running = task_has_idle_policy(p);
+ int h_nr_delayed = 0;
int task_new = !(flags & ENQUEUE_WAKEUP);
int rq_h_nr_running = rq->cfs.h_nr_running;
u64 slice = 0;
@@ -6974,6 +7005,9 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
if (p->in_iowait)
cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);

+ if (task_new)
+ h_nr_delayed = !!se->sched_delayed;
+
for_each_sched_entity(se) {
if (se->on_rq) {
if (se->sched_delayed)
@@ -6996,6 +7030,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)

cfs_rq->h_nr_running++;
cfs_rq->idle_h_nr_running += idle_h_nr_running;
+ cfs_rq->h_nr_delayed += h_nr_delayed;

if (cfs_rq_is_idle(cfs_rq))
idle_h_nr_running = 1;
@@ -7019,6 +7054,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)

cfs_rq->h_nr_running++;
cfs_rq->idle_h_nr_running += idle_h_nr_running;
+ cfs_rq->h_nr_delayed += h_nr_delayed;

if (cfs_rq_is_idle(cfs_rq))
idle_h_nr_running = 1;
@@ -7081,6 +7117,7 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)
struct task_struct *p = NULL;
int idle_h_nr_running = 0;
int h_nr_running = 0;
+ int h_nr_delayed = 0;
struct cfs_rq *cfs_rq;
u64 slice = 0;

@@ -7088,6 +7125,8 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)
p = task_of(se);
h_nr_running = 1;
idle_h_nr_running = task_has_idle_policy(p);
+ if (!task_sleep && !task_delayed)
+ h_nr_delayed = !!se->sched_delayed;
} else {
cfs_rq = group_cfs_rq(se);
slice = cfs_rq_min_slice(cfs_rq);
@@ -7105,6 +7144,7 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)

cfs_rq->h_nr_running -= h_nr_running;
cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+ cfs_rq->h_nr_delayed -= h_nr_delayed;

if (cfs_rq_is_idle(cfs_rq))
idle_h_nr_running = h_nr_running;
@@ -7143,6 +7183,7 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags)

cfs_rq->h_nr_running -= h_nr_running;
cfs_rq->idle_h_nr_running -= idle_h_nr_running;
+ cfs_rq->h_nr_delayed -= h_nr_delayed;

if (cfs_rq_is_idle(cfs_rq))
idle_h_nr_running = h_nr_running;
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index fc07382..fee75cc 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -321,7 +321,7 @@ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq)
{
if (___update_load_sum(now, &cfs_rq->avg,
scale_load_down(cfs_rq->load.weight),
- cfs_rq->h_nr_running,
+ cfs_rq->h_nr_running - cfs_rq->h_nr_delayed,
cfs_rq->curr != NULL)) {

___update_load_avg(&cfs_rq->avg, 1);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 76f5f53..1e494af 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -649,6 +649,7 @@ struct cfs_rq {
unsigned int h_nr_running; /* SCHED_{NORMAL,BATCH,IDLE} */
unsigned int idle_nr_running; /* SCHED_IDLE */
unsigned int idle_h_nr_running; /* SCHED_IDLE */
+ unsigned int h_nr_delayed;

s64 avg_vruntime;
u64 avg_load;
@@ -898,8 +899,11 @@ struct dl_rq {

static inline void se_update_runnable(struct sched_entity *se)
{
- if (!entity_is_task(se))
- se->runnable_weight = se->my_q->h_nr_running;
+ if (!entity_is_task(se)) {
+ struct cfs_rq *cfs_rq = se->my_q;
+
+ se->runnable_weight = cfs_rq->h_nr_running - cfs_rq->h_nr_delayed;
+ }
}

static inline long se_runnable(struct sched_entity *se)

Next message: tip-bot2 for K Prateek Nayak: "[tip: sched/core] sched/fair: Fix NEXT_BUDDY"
Previous message: tip-bot2 for Vincent Guittot: " [tip: sched/core] sched/fair: Fix sched_can_stop_tick() for fair tasks"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]