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Fixup (bore) EEVDF issue in #819 (#820)

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Signed-off-by: Peter Jung <admin@ptr1337.dev>
This commit is contained in:
ptr1337
2023-09-23 03:41:08 +02:00
committed by GitHub
parent 6aab0087df
commit a4c0ab6b9f
2 changed files with 1 additions and 516 deletions
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6
linux-tkg-config/prepare
View File

@@ -859,11 +859,7 @@ _tkg_srcprep() {
if [ "${_cpusched}" = "bore-eevdf" ]; then
_msg="Applying BORE-EEVDF patch"
if [ "$_kver" != "605" ]; then
curl "https://raw.githubusercontent.com/CachyOS/kernel-patches/master/${_basekernel}/sched/0001-bore-eevdf.patch" > "$srcdir"/0001-bore-eevdf.patch
else
curl "https://raw.githubusercontent.com/sirlucjan/kernel-patches/master/${_basekernel}/bore-eevdf-patches-v2-sep/0016-linux6.5-bore3.1.3.patch" > "$srcdir"/0001-bore-eevdf.patch
fi
curl "https://raw.githubusercontent.com/CachyOS/kernel-patches/master/${_basekernel}/sched/0001-bore-eevdf.patch" > "$srcdir"/0001-bore-eevdf.patch
tkgpatch="$srcdir/0001-bore-eevdf.patch" && _tkg_patcher
fi
fi

511
linux-tkg-patches/6.5/0003-eevdf.patch
View File

@@ -2896,514 +2896,3 @@ index 03db55504..f68919800 100644
--
2.42.0
From edbc7fe6658db891c80f244dc397f4e0247f6f3d Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 15 Sep 2023 00:48:55 +0200
Subject: [PATCH 13/15] sched/eevdf: Also update slice on placement
Tasks that never consume their full slice would not update their slice value.
This means that tasks that are spawned before the sysctl scaling keep their
original (UP) slice length.
Fixes: 147f3efaa241 ("sched/fair: Implement an EEVDF-like scheduling policy")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/sched/fair.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1cdc95725..efbcdc69c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4918,10 +4918,12 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) {}
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
- u64 vslice = calc_delta_fair(se->slice, se);
- u64 vruntime = avg_vruntime(cfs_rq);
+ u64 vslice, vruntime = avg_vruntime(cfs_rq);
s64 lag = 0;
+ se->slice = sysctl_sched_base_slice;
+ vslice = calc_delta_fair(se->slice, se);
+
/*
* Due to how V is constructed as the weighted average of entities,
* adding tasks with positive lag, or removing tasks with negative lag
--
2.42.0
From 0f1fadfb03ba9ba181e4631de8cd97ba765fae1d Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 15 Sep 2023 00:48:45 +0200
Subject: [PATCH 14/15] sched/eevdf: Delay dequeue
For tasks that have negative-lag (have received 'excess' service), delay the
dequeue and keep them in the runnable tree until they're elegible again. Or
rather, keep them until they're selected again, since finding their elegibility
crossover point is expensive.
The effect is a bit like sleeper bonus, the tasks keep contending for service
until either they get a wakeup or until they're selected again and are really
dequeued.
This means that any actual dequeue happens with positive lag (serviced owed)
and are more readily ran when wakeup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/sched.h | 1 +
kernel/sched/core.c | 41 +++++++++++++++++++++++++++++++++++------
kernel/sched/fair.c | 9 +++++++++
kernel/sched/features.h | 1 +
kernel/sched/sched.h | 3 ++-
5 files changed, 48 insertions(+), 7 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 35331c35f..d40d98313 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -891,6 +891,7 @@ struct task_struct {
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
unsigned sched_migrated:1;
+ unsigned sched_delayed:1;
/* Force alignment to the next boundary: */
unsigned :0;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8116ef56d..cfb0ffa69 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6551,6 +6551,16 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
# define SM_MASK_PREEMPT SM_PREEMPT
#endif
+static void __deschedule_task(struct rq *rq, struct task_struct *p)
+{
+ deactivate_task(rq, p, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
+
+ if (p->in_iowait) {
+ atomic_inc(&rq->nr_iowait);
+ delayacct_blkio_start();
+ }
+}
+
/*
* __schedule() is the main scheduler function.
*
@@ -6663,17 +6673,36 @@ static void __sched notrace __schedule(unsigned int sched_mode)
*
* After this, schedule() must not care about p->state any more.
*/
- deactivate_task(rq, prev, DEQUEUE_SLEEP | DEQUEUE_NOCLOCK);
+ if (!(sched_feat(DELAY_DEQUEUE) &&
+ prev->sched_class->eligible_task &&
+ !prev->sched_class->eligible_task(rq, prev)))
+ __deschedule_task(rq, prev);
+ else
+ prev->sched_delayed = 1;
+ }
+ switch_count = &prev->nvcsw;
+ }
+
+ for (struct task_struct *tmp = prev;;) {
- if (prev->in_iowait) {
- atomic_inc(&rq->nr_iowait);
- delayacct_blkio_start();
+ next = pick_next_task(rq, tmp, &rf);
+ if (unlikely(tmp != prev))
+ finish_task(tmp);
+
+ if (sched_feat(DELAY_DEQUEUE) && unlikely(next->sched_delayed)) {
+ next->sched_delayed = 0;
+ if (READ_ONCE(next->__state)) {
+ prepare_task(next);
+ smp_wmb();
+ __deschedule_task(rq, next);
+ tmp = next;
+ continue;
}
}
- switch_count = &prev->nvcsw;
+
+ break;
}
- next = pick_next_task(rq, prev, &rf);
clear_tsk_need_resched(prev);
clear_preempt_need_resched();
#ifdef CONFIG_SCHED_DEBUG
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index efbcdc69c..729507e40 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8174,6 +8174,14 @@ static struct task_struct *__pick_next_task_fair(struct rq *rq)
return pick_next_task_fair(rq, NULL, NULL);
}
+static bool eligible_task_fair(struct rq *rq, struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ return entity_eligible(cfs_rq, se);
+}
+
/*
* Account for a descheduled task:
*/
@@ -12628,6 +12636,7 @@ DEFINE_SCHED_CLASS(fair) = {
.check_preempt_curr = check_preempt_wakeup,
+ .eligible_task = eligible_task_fair,
.pick_next_task = __pick_next_task_fair,
.put_prev_task = put_prev_task_fair,
.set_next_task = set_next_task_fair,
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 546d212ef..5ae5a6f92 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -7,6 +7,7 @@
SCHED_FEAT(PLACE_LAG, true)
SCHED_FEAT(PLACE_DEADLINE_INITIAL, true)
SCHED_FEAT(RUN_TO_PARITY, true)
+SCHED_FEAT(DELAY_DEQUEUE, true)
/*
* Prefer to schedule the task we woke last (assuming it failed
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 576d371c8..c18ab7c2f 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2219,6 +2219,7 @@ struct sched_class {
void (*check_preempt_curr)(struct rq *rq, struct task_struct *p, int flags);
+ bool (*eligible_task)(struct rq *rq, struct task_struct *p);
struct task_struct *(*pick_next_task)(struct rq *rq);
void (*put_prev_task)(struct rq *rq, struct task_struct *p);
@@ -2272,7 +2273,7 @@ struct sched_class {
static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
{
- WARN_ON_ONCE(rq->curr != prev);
+// WARN_ON_ONCE(rq->curr != prev);
prev->sched_class->put_prev_task(rq, prev);
}
--
2.42.0
From 4aba3e1c3bbe4a36d4b9e405be8a66d7c10d6495 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon, 22 May 2023 13:46:30 +0200
Subject: [PATCH 15/15] sched/eevdf: Use sched_attr::sched_runtime to set
request/slice suggestion
Allow applications to directly set a suggested request/slice length using
sched_attr::sched_runtime.
The implementation clamps the value to: 0.1[ms] <= slice <= 100[ms]
which is 1/10 the size of HZ=1000 and 10 times the size of HZ=100.
Applications should strive to use their periodic runtime at a high
confidence interval (95%+) as the target slice. Using a smaller slice
will introduce undue preemptions, while using a larger value will
increase latency.
For all the following examples assume a scheduling quantum of 8, and for
consistency all examples have W=4:
{A,B,C,D}(w=1,r=8):
ABCD...
+---+---+---+---
t=0, V=1.5 t=1, V=3.5
A |------< A |------<
B |------< B |------<
C |------< C |------<
D |------< D |------<
---+*------+-------+--- ---+--*----+-------+---
t=2, V=5.5 t=3, V=7.5
A |------< A |------<
B |------< B |------<
C |------< C |------<
D |------< D |------<
---+----*--+-------+--- ---+------*+-------+---
Note: 4 identical tasks in FIFO order
~~~
{A,B}(w=1,r=16) C(w=2,r=16)
AACCBBCC...
+---+---+---+---
t=0, V=1.25 t=2, V=5.25
A |--------------< A |--------------<
B |--------------< B |--------------<
C |------< C |------<
---+*------+-------+--- ---+----*--+-------+---
t=4, V=8.25 t=6, V=12.25
A |--------------< A |--------------<
B |--------------< B |--------------<
C |------< C |------<
---+-------*-------+--- ---+-------+---*---+---
Note: 1 heavy task -- because q=8, double r such that the deadline of the w=2
task doesn't go below q.
Note: observe the full schedule becomes: W*max(r_i/w_i) = 4*2q = 8q in length.
Note: the period of the heavy task is half the full period at:
W*(r_i/w_i) = 4*(2q/2) = 4q
~~~
{A,C,D}(w=1,r=16) B(w=1,r=8):
BAACCBDD...
+---+---+---+---
t=0, V=1.5 t=1, V=3.5
A |--------------< A |---------------<
B |------< B |------<
C |--------------< C |--------------<
D |--------------< D |--------------<
---+*------+-------+--- ---+--*----+-------+---
t=3, V=7.5 t=5, V=11.5
A |---------------< A |---------------<
B |------< B |------<
C |--------------< C |--------------<
D |--------------< D |--------------<
---+------*+-------+--- ---+-------+--*----+---
t=6, V=13.5
A |---------------<
B |------<
C |--------------<
D |--------------<
---+-------+----*--+---
Note: 1 short task -- again double r so that the deadline of the short task
won't be below q. Made B short because its not the leftmost task, but is
eligible with the 0,1,2,3 spread.
Note: like with the heavy task, the period of the short task observes:
W*(r_i/w_i) = 4*(1q/1) = 4q
~~~
A(w=1,r=16) B(w=1,r=8) C(w=2,r=16)
BCCAABCC...
+---+---+---+---
t=0, V=1.25 t=1, V=3.25
A |--------------< A |--------------<
B |------< B |------<
C |------< C |------<
---+*------+-------+--- ---+--*----+-------+---
t=3, V=7.25 t=5, V=11.25
A |--------------< A |--------------<
B |------< B |------<
C |------< C |------<
---+------*+-------+--- ---+-------+--*----+---
t=6, V=13.25
A |--------------<
B |------<
C |------<
---+-------+----*--+---
Note: 1 heavy and 1 short task -- combine them all.
Note: both the short and heavy task end up with a period of 4q
~~~
A(w=1,r=16) B(w=2,r=16) C(w=1,r=8)
BBCAABBC...
+---+---+---+---
t=0, V=1 t=2, V=5
A |--------------< A |--------------<
B |------< B |------<
C |------< C |------<
---+*------+-------+--- ---+----*--+-------+---
t=3, V=7 t=5, V=11
A |--------------< A |--------------<
B |------< B |------<
C |------< C |------<
---+------*+-------+--- ---+-------+--*----+---
t=7, V=15
A |--------------<
B |------<
C |------<
---+-------+------*+---
Note: as before but permuted
~~~
From all this it can be deduced that, for the steady state:
- the total period (P) of a schedule is: W*max(r_i/w_i)
- the average period of a task is: W*(r_i/w_i)
- each task obtains the fair share: w_i/W of each full period P
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/sched.h | 3 +++
kernel/sched/core.c | 33 ++++++++++++++++++++++++++-------
kernel/sched/fair.c | 6 ++++--
3 files changed, 33 insertions(+), 9 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d40d98313..93c03b162 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -555,6 +555,9 @@ struct sched_entity {
struct list_head group_node;
unsigned int on_rq;
+ unsigned int custom_slice : 1;
+ /* 31 bits hole */
+
u64 exec_start;
u64 sum_exec_runtime;
u64 prev_sum_exec_runtime;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index cfb0ffa69..1ae5a8272 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4502,7 +4502,6 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
p->se.nr_migrations = 0;
p->se.vruntime = 0;
p->se.vlag = 0;
- p->se.slice = sysctl_sched_base_slice;
INIT_LIST_HEAD(&p->se.group_node);
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -4756,6 +4755,8 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
p->prio = p->normal_prio = p->static_prio;
set_load_weight(p, false);
+ p->se.custom_slice = 0;
+ p->se.slice = sysctl_sched_base_slice;
/*
* We don't need the reset flag anymore after the fork. It has
@@ -7556,10 +7557,20 @@ static void __setscheduler_params(struct task_struct *p,
p->policy = policy;
- if (dl_policy(policy))
+ if (dl_policy(policy)) {
__setparam_dl(p, attr);
- else if (fair_policy(policy))
+ } else if (fair_policy(policy)) {
p->static_prio = NICE_TO_PRIO(attr->sched_nice);
+ if (attr->sched_runtime) {
+ p->se.custom_slice = 1;
+ p->se.slice = clamp_t(u64, attr->sched_runtime,
+ NSEC_PER_MSEC/10, /* HZ=1000 * 10 */
+ NSEC_PER_MSEC*100); /* HZ=100 / 10 */
+ } else {
+ p->se.custom_slice = 0;
+ p->se.slice = sysctl_sched_base_slice;
+ }
+ }
/*
* __sched_setscheduler() ensures attr->sched_priority == 0 when
@@ -7744,7 +7755,9 @@ static int __sched_setscheduler(struct task_struct *p,
* but store a possible modification of reset_on_fork.
*/
if (unlikely(policy == p->policy)) {
- if (fair_policy(policy) && attr->sched_nice != task_nice(p))
+ if (fair_policy(policy) &&
+ (attr->sched_nice != task_nice(p) ||
+ (attr->sched_runtime && attr->sched_runtime != p->se.slice)))
goto change;
if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
goto change;
@@ -7890,6 +7903,9 @@ static int _sched_setscheduler(struct task_struct *p, int policy,
.sched_nice = PRIO_TO_NICE(p->static_prio),
};
+ if (p->se.custom_slice)
+ attr.sched_runtime = p->se.slice;
+
/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
@@ -8066,12 +8082,14 @@ static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *a
static void get_params(struct task_struct *p, struct sched_attr *attr)
{
- if (task_has_dl_policy(p))
+ if (task_has_dl_policy(p)) {
__getparam_dl(p, attr);
- else if (task_has_rt_policy(p))
+ } else if (task_has_rt_policy(p)) {
attr->sched_priority = p->rt_priority;
- else
+ } else {
attr->sched_nice = task_nice(p);
+ attr->sched_runtime = p->se.slice;
+ }
}
/**
@@ -10090,6 +10108,7 @@ void __init sched_init(void)
}
set_load_weight(&init_task, false);
+ init_task.se.slice = sysctl_sched_base_slice,
/*
* The boot idle thread does lazy MMU switching as well:
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 729507e40..51e19a1fb 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -973,7 +973,8 @@ static void update_deadline(struct cfs_rq *cfs_rq, struct sched_entity *se)
* nice) while the request time r_i is determined by
* sysctl_sched_base_slice.
*/
- se->slice = sysctl_sched_base_slice;
+ if (!se->custom_slice)
+ se->slice = sysctl_sched_base_slice;
/*
* EEVDF: vd_i = ve_i + r_i / w_i
@@ -4921,7 +4922,8 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
u64 vslice, vruntime = avg_vruntime(cfs_rq);
s64 lag = 0;
- se->slice = sysctl_sched_base_slice;
+ if (!se->custom_slice)
+ se->slice = sysctl_sched_base_slice;
vslice = calc_delta_fair(se->slice, se);
/*
--
2.42.0