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linux-pikaos-template/patches/0003-bore.patch
ferrreo 3ad8571d9c 6.4RC6 + Add BORE/EEVDF
2023-06-14 20:49:41 +01:00

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From 32c617afc05751783be3eb0f5a1d15e31dfc7919 Mon Sep 17 00:00:00 2001
From: Piotr Gorski <lucjan.lucjanov@gmail.com>
Date: Thu, 8 Jun 2023 11:14:23 +0200
Subject: [PATCH] bore-cachy
Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
---
include/linux/sched.h | 10 +++
init/Kconfig | 20 ++++++
kernel/sched/core.c | 62 ++++++++++++++++++
kernel/sched/debug.c | 3 +
kernel/sched/fair.c | 136 ++++++++++++++++++++++++++++++++++++++++
kernel/sched/features.h | 8 +++
6 files changed, 239 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index eed5d65b8..38fbebe4d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -557,6 +557,12 @@ struct sched_entity {
u64 sum_exec_runtime;
u64 vruntime;
u64 prev_sum_exec_runtime;
+#ifdef CONFIG_SCHED_BORE
+ u64 prev_burst_time;
+ u64 burst_time;
+ u64 max_burst_time;
+ u8 penalty_score;
+#endif // CONFIG_SCHED_BORE
u64 nr_migrations;
@@ -985,6 +991,10 @@ struct task_struct {
struct list_head children;
struct list_head sibling;
struct task_struct *group_leader;
+#ifdef CONFIG_SCHED_BORE
+ u64 child_burst_cache;
+ u64 child_burst_last_cached;
+#endif // CONFIG_SCHED_BORE
/*
* 'ptraced' is the list of tasks this task is using ptrace() on.
diff --git a/init/Kconfig b/init/Kconfig
index 0147b4a33..4ab7e154b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1290,6 +1290,26 @@ config CHECKPOINT_RESTORE
If unsure, say N here.
+config SCHED_BORE
+ bool "Burst-Oriented Response Enhancer"
+ default y
+ help
+ In Desktop and Mobile computing, one might prefer interactive
+ tasks to keep responsive no matter what they run in the background.
+
+ Enabling this kernel feature modifies the scheduler to discriminate
+ tasks by their burst time (runtime since it last went sleeping or
+ yielding state) and prioritize those that run less bursty.
+ Such tasks usually include window compositor, widgets backend,
+ terminal emulator, video playback, games and so on.
+ With a little impact to scheduling fairness, it may improve
+ responsiveness especially under heavy background workload.
+
+ You can turn it off by setting the sysctl kernel.sched_bore = 0.
+ Enabling this feature implies NO_GENTLE_FAIR_SLEEPERS by default.
+
+ If unsure say Y here.
+
config SCHED_AUTOGROUP
bool "Automatic process group scheduling"
select CGROUPS
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bcb3a7e68..a0f227344 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4484,6 +4484,57 @@ int wake_up_state(struct task_struct *p, unsigned int state)
return try_to_wake_up(p, state, 0);
}
+#ifdef CONFIG_SCHED_BORE
+#define CHILD_BURST_CUTOFF_BITS 9
+extern unsigned int sched_burst_cache_lifetime;
+
+void __init sched_init_bore(void) {
+ init_task.child_burst_cache = 0;
+ init_task.child_burst_last_cached = 0;
+ init_task.se.prev_burst_time = 0;
+ init_task.se.burst_time = 0;
+ init_task.se.max_burst_time = 0;
+}
+
+void inline __sched_fork_bore(struct task_struct *p) {
+ p->child_burst_cache = 0;
+ p->child_burst_last_cached = 0;
+ p->se.burst_time = 0;
+}
+
+static inline void update_task_child_burst_time_cache(struct task_struct *p) {
+ u64 sum = 0, avg_burst_time = 0;
+ u32 cnt = 0;
+ struct task_struct *child;
+
+ read_lock(&tasklist_lock);
+ list_for_each_entry(child, &p->children, sibling) {
+ cnt++;
+ sum += child->se.max_burst_time >> CHILD_BURST_CUTOFF_BITS;
+ }
+ read_unlock(&tasklist_lock);
+
+ if (cnt) avg_burst_time = div_u64(sum, cnt) << CHILD_BURST_CUTOFF_BITS;
+ p->child_burst_cache = max(avg_burst_time, p->se.max_burst_time);
+}
+
+static void update_task_initial_burst_time(struct task_struct *task) {
+ struct sched_entity *se = &task->se;
+ struct task_struct *par = task->real_parent;
+ u64 ktime = ktime_to_ns(ktime_get());
+
+ if (likely(par)) {
+ if (par->child_burst_last_cached + sched_burst_cache_lifetime < ktime) {
+ par->child_burst_last_cached = ktime;
+ update_task_child_burst_time_cache(par);
+ }
+ se->prev_burst_time = max(se->prev_burst_time, par->child_burst_cache);
+ }
+
+ se->max_burst_time = se->prev_burst_time;
+}
+#endif // CONFIG_SCHED_BORE
+
/*
* Perform scheduler related setup for a newly forked process p.
* p is forked by current.
@@ -4500,6 +4551,9 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
p->se.prev_sum_exec_runtime = 0;
p->se.nr_migrations = 0;
p->se.vruntime = 0;
+#ifdef CONFIG_SCHED_BORE
+ __sched_fork_bore(p);
+#endif // CONFIG_SCHED_BORE
INIT_LIST_HEAD(&p->se.group_node);
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -4726,6 +4780,9 @@ late_initcall(sched_core_sysctl_init);
int sched_fork(unsigned long clone_flags, struct task_struct *p)
{
__sched_fork(clone_flags, p);
+#ifdef CONFIG_SCHED_BORE
+ update_task_initial_burst_time(p);
+#endif // CONFIG_SCHED_BORE
/*
* We mark the process as NEW here. This guarantees that
* nobody will actually run it, and a signal or other external
@@ -9922,6 +9979,11 @@ void __init sched_init(void)
BUG_ON(&dl_sched_class != &stop_sched_class + 1);
#endif
+#ifdef CONFIG_SCHED_BORE
+ sched_init_bore();
+ printk(KERN_INFO "BORE (Burst-Oriented Response Enhancer) CPU Scheduler modification 2.4.0 by Masahito Suzuki");
+#endif // CONFIG_SCHED_BORE
+
wait_bit_init();
#ifdef CONFIG_FAIR_GROUP_SCHED
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 066ff1c8a..4bc07d405 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -593,6 +593,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_sleep_runtime)),
SPLIT_NS(schedstat_val_or_zero(p->stats.sum_block_runtime)));
+#ifdef CONFIG_SCHED_BORE
+ SEQ_printf(m, " %2d", p->se.penalty_score);
+#endif
#ifdef CONFIG_NUMA_BALANCING
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
#endif
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9fe8288b1..ac29ac350 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -19,6 +19,9 @@
*
* Adaptive scheduling granularity, math enhancements by Peter Zijlstra
* Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
+ *
+ * Burst-Oriented Response Enhancer (BORE) CPU Scheduler
+ * Copyright (C) 2021-2023 Masahito Suzuki <firelzrd@gmail.com>
*/
#include <linux/energy_model.h>
#include <linux/mmap_lock.h>
@@ -140,6 +143,61 @@ static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+#ifdef CONFIG_SCHED_BORE
+unsigned int __read_mostly sched_bore = 1;
+unsigned int __read_mostly sched_burst_cache_lifetime = 15000000;
+unsigned int __read_mostly sched_burst_penalty_offset = 12;
+unsigned int __read_mostly sched_burst_penalty_scale = 1292;
+unsigned int __read_mostly sched_burst_smoothness = 1;
+static int three = 3;
+static int sixty_four = 64;
+static int maxval_12_bits = 4095;
+
+#define FIXED_SHIFT 10
+#define FIXED_ONE (1 << FIXED_SHIFT)
+typedef u32 fixed;
+
+static void update_burst_score(struct sched_entity *se) {
+ u64 burst_time = se->max_burst_time;
+
+ int msb = fls64(burst_time);
+ fixed integer_part = msb << FIXED_SHIFT;
+ fixed fractional_part = burst_time << (64 - msb) << 1 >> (64 - FIXED_SHIFT);
+ fixed greed = integer_part | fractional_part;
+
+ fixed tolerance = sched_burst_penalty_offset << FIXED_SHIFT;
+ fixed penalty = max(0, (s32)greed - (s32)tolerance);
+ fixed scaled_penalty = penalty * sched_burst_penalty_scale >> 10;
+
+ u8 score = min(39U, scaled_penalty >> FIXED_SHIFT);
+ se->penalty_score = score;
+}
+
+static inline u64 penalty_scale(u64 delta, struct sched_entity *se) {
+ return mul_u64_u32_shr(delta, sched_prio_to_wmult[se->penalty_score], 22);
+}
+
+static inline u64 __binary_smooth(u64 new, u64 old, unsigned int smoothness) {
+ return (new + old * ((1 << smoothness) - 1)) >> smoothness;
+}
+
+void restart_burst(struct sched_entity *se) {
+ se->max_burst_time = se->prev_burst_time = __binary_smooth(
+ se->burst_time, se->prev_burst_time, sched_burst_smoothness);
+ se->burst_time = 0;
+}
+
+#define calc_delta_fair(delta, se) __calc_delta_fair(delta, se, true)
+#define calc_delta_fair_unscaled(delta, se) __calc_delta_fair(delta, se, false)
+static inline u64
+__calc_delta_fair(u64 delta, struct sched_entity *se, bool bscale);
+
+static s64 wakeup_preempt_backstep_delta(u64 rtime, struct sched_entity *se) {
+ u64 delta = calc_delta_fair_unscaled(rtime, se);
+ return delta - penalty_scale(delta, se);
+}
+#endif // CONFIG_SCHED_BORE
+
int sched_thermal_decay_shift;
static int __init setup_sched_thermal_decay_shift(char *str)
{
@@ -203,6 +261,51 @@ static unsigned int sysctl_numa_balancing_promote_rate_limit = 65536;
#ifdef CONFIG_SYSCTL
static struct ctl_table sched_fair_sysctls[] = {
+#ifdef CONFIG_SCHED_BORE
+ {
+ .procname = "sched_bore",
+ .data = &sched_bore,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ {
+ .procname = "sched_burst_cache_lifetime",
+ .data = &sched_burst_cache_lifetime,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+ {
+ .procname = "sched_burst_penalty_offset",
+ .data = &sched_burst_penalty_offset,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &sixty_four,
+ },
+ {
+ .procname = "sched_burst_penalty_scale",
+ .data = &sched_burst_penalty_scale,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &maxval_12_bits,
+ },
+ {
+ .procname = "sched_burst_smoothness",
+ .data = &sched_burst_smoothness,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = &three,
+ },
+#endif // CONFIG_SCHED_BORE
{
.procname = "sched_child_runs_first",
.data = &sysctl_sched_child_runs_first,
@@ -724,11 +827,19 @@ int sched_update_scaling(void)
/*
* delta /= w
*/
+#ifdef CONFIG_SCHED_BORE
+static inline u64
+__calc_delta_fair(u64 delta, struct sched_entity *se, bool bscale)
+#else // CONFIG_SCHED_BORE
static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se)
+#endif // CONFIG_SCHED_BORE
{
if (unlikely(se->load.weight != NICE_0_LOAD))
delta = __calc_delta(delta, NICE_0_LOAD, &se->load);
+#ifdef CONFIG_SCHED_BORE
+ if (bscale && sched_bore) delta = penalty_scale(delta, se);
+#endif // CONFIG_SCHED_BORE
return delta;
}
@@ -938,6 +1049,14 @@ static void update_curr(struct cfs_rq *cfs_rq)
curr->sum_exec_runtime += delta_exec;
schedstat_add(cfs_rq->exec_clock, delta_exec);
+#ifdef CONFIG_SCHED_BORE
+ curr->burst_time += delta_exec;
+ curr->max_burst_time = max(curr->max_burst_time, curr->burst_time);
+ update_burst_score(curr);
+ if (sched_bore)
+ curr->vruntime += penalty_scale(calc_delta_fair(delta_exec, curr), curr);
+ else
+#endif // CONFIG_SCHED_BORE
curr->vruntime += calc_delta_fair(delta_exec, curr);
update_min_vruntime(cfs_rq);
@@ -6410,6 +6529,9 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
util_est_dequeue(&rq->cfs, p);
for_each_sched_entity(se) {
+#ifdef CONFIG_SCHED_BORE
+ if (task_sleep) restart_burst(se);
+#endif // CONFIG_SCHED_BORE
cfs_rq = cfs_rq_of(se);
dequeue_entity(cfs_rq, se, flags);
@@ -7844,7 +7966,11 @@ static unsigned long wakeup_gran(struct sched_entity *se)
* This is especially important for buddies when the leftmost
* task is higher priority than the buddy.
*/
+#ifdef CONFIG_SCHED_BORE
+ return calc_delta_fair_unscaled(gran, se);
+#else // CONFIG_SCHED_BORE
return calc_delta_fair(gran, se);
+#endif // CONFIG_SCHED_BORE
}
/*
@@ -7865,6 +7991,13 @@ static int
wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
{
s64 gran, vdiff = curr->vruntime - se->vruntime;
+#ifdef CONFIG_SCHED_BORE
+ if (sched_bore) {
+ u64 rtime = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ vdiff += wakeup_preempt_backstep_delta(rtime, curr)
+ - wakeup_preempt_backstep_delta(rtime, se);
+ }
+#endif // CONFIG_SCHED_BORE
if (vdiff <= 0)
return -1;
@@ -8210,6 +8343,9 @@ static void yield_task_fair(struct rq *rq)
struct task_struct *curr = rq->curr;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
struct sched_entity *se = &curr->se;
+#ifdef CONFIG_SCHED_BORE
+ restart_burst(se);
+#endif // CONFIG_SCHED_BORE
/*
* Are we the only task in the tree?
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 9e390eb82..696ea7081 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -4,7 +4,11 @@
* them to run sooner, but does not allow tons of sleepers to
* rip the spread apart.
*/
+#ifdef CONFIG_SCHED_BORE
+SCHED_FEAT(GENTLE_FAIR_SLEEPERS, false)
+#else // CONFIG_SCHED_BORE
SCHED_FEAT(GENTLE_FAIR_SLEEPERS, true)
+#endif // CONFIG_SCHED_BORE
/*
* Place new tasks ahead so that they do not starve already running
@@ -17,7 +21,11 @@ SCHED_FEAT(START_DEBIT, true)
* wakeup-preemption), since its likely going to consume data we
* touched, increases cache locality.
*/
+#ifdef CONFIG_SCHED_BORE
+SCHED_FEAT(NEXT_BUDDY, true)
+#else // CONFIG_SCHED_BORE
SCHED_FEAT(NEXT_BUDDY, false)
+#endif // CONFIG_SCHED_BORE
/*
* Prefer to schedule the task that ran last (when we did
--
2.41.0.rc2
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