linux-pikaos-template/patches/0004-bore.patch

From e016cce088886f56617becc8fcc598a0114e4faa Mon Sep 17 00:00:00 2001
From: Peter Jung <admin@ptr1337.dev>
Date: Sat, 11 Mar 2023 18:44:19 +0100
Subject: [PATCH] bore-eevdf

Signed-off-by: Peter Jung <admin@ptr1337.dev>
---
 include/linux/sched.h |   5 ++
 init/Kconfig          |  20 +++++++
 kernel/sched/core.c   |  29 ++++++++++
 kernel/sched/debug.c  |   3 +
 kernel/sched/fair.c   | 124 +++++++++++++++++++++++++++++++++++++++++-
 5 files changed, 180 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 764df627c243..f912da35db34 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -558,6 +558,11 @@ 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;
+	u8				burst_score;
+#endif // CONFIG_SCHED_BORE
 	s64				lag;
 	u64				slice;
 
diff --git a/init/Kconfig b/init/Kconfig
index 748a9491ca12..d10f1e6257cd 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1318,6 +1318,26 @@ 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 9db5f9ec9022..1f1e1f586407 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4418,6 +4418,21 @@ int wake_up_state(struct task_struct *p, unsigned int state)
 	return try_to_wake_up(p, state, 0);
 }
 
+#ifdef CONFIG_SCHED_BORE
+static inline void sched_fork_update_prev_burst(struct task_struct *p)
+{
+	struct task_struct *sib;
+	u32 cnt = 0;
+	u64 sum = 0, avg = 0;
+	list_for_each_entry(sib, &p->sibling, sibling) {
+		cnt++;
+		sum += sib->se.prev_burst_time >> 8;
+	}
+	if (cnt) avg = div_u64(sum, cnt) << 8;
+	if (p->se.prev_burst_time < avg) p->se.prev_burst_time = avg;
+}
+#endif // CONFIG_SCHED_BORE
+
 /*
  * Perform scheduler related setup for a newly forked process p.
  * p is forked by current.
@@ -4434,6 +4449,9 @@ 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
+	p->se.burst_time      = 0;
+#endif // CONFIG_SCHED_BORE
 	p->se.dur_avg			= 0;
 	p->se.prev_sleep_sum_runtime	= 0;
 	p->se.lag			= 0;
@@ -4664,6 +4682,10 @@ 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
+	sched_fork_update_prev_burst(p);
+	p->se.burst_time = 0;
+#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
@@ -9153,6 +9175,9 @@ void __init init_idle(struct task_struct *idle, int cpu)
 
 	idle->__state = TASK_RUNNING;
 	idle->se.exec_start = sched_clock();
+#ifdef CONFIG_SCHED_BORE
+	idle->se.prev_burst_time = 0;
+#endif //CONFIG_SCHED_BORE
 	/*
 	 * PF_KTHREAD should already be set at this point; regardless, make it
 	 * look like a proper per-CPU kthread.
@@ -9820,6 +9845,10 @@ void __init sched_init(void)
 	BUG_ON(&dl_sched_class != &stop_sched_class + 1);
 #endif
 
+#ifdef CONFIG_SCHED_BORE
+	printk(KERN_INFO "BORE (Burst-Oriented Response Enhancer) CPU Scheduler modification for 1.7-eevdf2 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 fe9edfa43f65..3672df7c1f6a 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -551,6 +551,9 @@ 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.burst_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 c40b775452bc..1e4ca5419a11 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 Masahito Suzuki <firelzrd@gmail.com>
  */
 #include <linux/energy_model.h>
 #include <linux/mmap_lock.h>
@@ -141,6 +144,16 @@ 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_penalty_scale = 1280;
+unsigned int __read_mostly sched_burst_granularity   = 6;
+unsigned int __read_mostly sched_burst_smoothness    = 2;
+static int three          = 3;
+static int sixty_four     = 64;
+static int maxval_12_bits = 4095;
+#endif // CONFIG_SCHED_BORE
+
 int sched_thermal_decay_shift;
 static int __init setup_sched_thermal_decay_shift(char *str)
 {
@@ -204,6 +217,44 @@ 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_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_granularity",
+		.data		= &sched_burst_granularity,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= &sixty_four,
+	},
+	{
+		.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,
@@ -1182,6 +1233,39 @@ static void update_tg_load_avg(struct cfs_rq *cfs_rq)
 }
 #endif /* CONFIG_SMP */
 
+#ifdef CONFIG_SCHED_BORE
+static inline void update_burst_score(struct sched_entity *se) {
+	u64 burst_time;
+	s32 bits;
+	u32 intgr, fdigs, dec10;
+	
+	burst_time = max(se->burst_time, se->prev_burst_time);
+	bits = fls64(burst_time);
+	intgr = max((u32)bits, sched_burst_granularity) - sched_burst_granularity;
+	fdigs = max(bits - 1, (s32)sched_burst_granularity);
+	dec10 = (intgr << 10) | (burst_time << (64 - fdigs) >> 54);
+	se->burst_score = min((u32)39, dec10 * sched_burst_penalty_scale >> 20);
+}
+
+static u64 burst_scale(u64 delta, struct sched_entity *se) {
+	return mul_u64_u32_shr(delta, sched_prio_to_wmult[se->burst_score], 22);
+}
+
+static u64 calc_delta_fair_bscale(u64 delta, struct sched_entity *se) {
+	return burst_scale(calc_delta_fair(delta, se), se);
+}
+
+static inline u64 binary_smooth(u64 old, u64 new, unsigned int smoothness) {
+	return (new + old * ((1 << smoothness) - 1)) >> smoothness;
+}
+
+static inline void reset_burst(struct sched_entity *se) {
+	se->prev_burst_time = binary_smooth(
+		se->prev_burst_time, se->burst_time, sched_burst_smoothness);
+	se->burst_time = 0;
+}
+#endif // CONFIG_SCHED_BORE
+
 /*
  * Update the current task's runtime statistics.
  */
@@ -1211,6 +1295,13 @@ 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;
+	update_burst_score(curr);
+	if (sched_bore)
+		curr->vruntime += calc_delta_fair_bscale(delta_exec, curr);
+	else
+#endif // CONFIG_SCHED_BORE
 	curr->vruntime += calc_delta_fair(delta_exec, curr);
 	/*
 	 * XXX: strictly: vd_i += N*r_i/w_i such that: vd_i > ve_i
@@ -5283,6 +5374,11 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 	se->prev_sum_exec_runtime = se->sum_exec_runtime;
 }
 
+#ifdef CONFIG_SCHED_BORE
+static int
+wakeup_preempt_entity_bscale(struct sched_entity *curr,
+                             struct sched_entity *se, bool do_scale);
+#endif // CONFIG_SCHED_BORE
 static int
 wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
 
@@ -5330,7 +5426,13 @@ pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 			se = second;
 	}
 
-	if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) {
+#ifdef CONFIG_SCHED_BORE
+	if (cfs_rq->next && wakeup_preempt_entity_bscale(
+		                  cfs_rq->next, left, sched_bore & 2) < 1)
+#else // CONFIG_SCHED_BORE
+	if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
+#endif // CONFIG_SCHED_BORE
+	{
 		/*
 		 * Someone really wants this to run. If it's not unfair, run it.
 		 */
@@ -6615,6 +6717,9 @@ 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) reset_burst(se);
+#endif // CONFIG_SCHED_BORE
 		cfs_rq = cfs_rq_of(se);
 		dequeue_entity(cfs_rq, se, flags);
 
@@ -8070,7 +8175,12 @@ static unsigned long wakeup_gran(struct sched_entity *se)
  *
  */
 static int
+#ifdef CONFIG_SCHED_BORE
+wakeup_preempt_entity_bscale(struct sched_entity *curr,
+                             struct sched_entity *se, bool do_scale)
+#else // CONFIG_SCHED_BORE
 wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
+#endif // CONFIG_SCHED_BORE
 {
 	s64 gran, vdiff = curr->vruntime - se->vruntime;
 
@@ -8078,11 +8188,20 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
 		return -1;
 
 	gran = wakeup_gran(se);
+#ifdef CONFIG_SCHED_BORE
+	if (do_scale) gran = burst_scale(gran, se);
+#endif // CONFIG_SCHED_BORE
 	if (vdiff > gran)
 		return 1;
 
 	return 0;
 }
+#ifdef CONFIG_SCHED_BORE
+static int wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
+{
+	return wakeup_preempt_entity_bscale(curr, se, false);
+}
+#endif // CONFIG_SCHED_BORE
 
 static void set_last_buddy(struct sched_entity *se)
 {
@@ -8430,6 +8549,9 @@ 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
+	reset_burst(se);
+#endif // CONFIG_SCHED_BORE
 
 	/*
 	 * Are we the only task in the tree?
-- 
2.40.0.rc2