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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: "Jan Alexander Steffens (heftig)" <jan.steffens@gmail.com>
Date: Mon, 27 Jan 2020 18:28:13 +0100
Subject: [PATCH] ZEN: INTERACTIVE: Tune CFS for interactivity
5.7:
Take "sysctl_sched_nr_migrate" tune from early XanMod builds of 128. As
of 5.7, XanMod uses 256 but that may affect applications that require
timely response to IRQs.
5.15:
Per comment [1] on our ZEN INTERACTIVE commit, reducing the cost of
migration causes the system less responsive under high load. Most
likely the combination of reduced migration cost + the higher number of
tasks that can be migrated at once contributes to this.
To better handle this situation, restore the mainline migration cost
value and also reduce the max number of tasks that can be migrated in
batch from 128 to 64.
If this doesn't help, we'll restore the reduced migration cost and keep
total number of tasks that can be migrated at once to 32.
[1] https://github.com/zen-kernel/zen-kernel/commit/be5ba234ca0a5aabe74bfc7e1f636f085bd3823c#commitcomment-63159674
---
init/Kconfig | 8 ++++++++
kernel/sched/core.c | 4 +++-
kernel/sched/fair.c | 23 +++++++++++++++++++++++
3 files changed, 34 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index bf583d6054804b213f3d6a484403ee3197b8760b..7c832dd05941a231ad1c7dbbeeb914811d540591 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -126,6 +126,14 @@ config ZEN_INTERACTIVE
Background-reclaim hugepages...: no -> yes
MG-LRU minimum cache TTL.......: 0 -> 1000 ms
+ --- CFS CPU Scheduler ----------------------------------
+
+ Scheduling latency.............: 6 -> 4 ms
+ Minimal granularity............: 0.75 -> 0.4 ms
+ Wakeup granularity.............: 1 -> 0.5 ms
+ Bandwidth slice size...........: 5 -> 3 ms
+ Task rebalancing threshold.....: 32 -> 64
+
config BROKEN
bool
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d58c0389eb23c9fb8f87afc73b2bc7c5a0cd4439..9987bb069ef0f4aca573f38fa7a9a5b35d29f3fb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -139,7 +139,9 @@ __read_mostly int sysctl_resched_latency_warn_once = 1;
* Number of tasks to iterate in a single balance run.
* Limited because this is done with IRQs disabled.
*/
-#ifdef CONFIG_PREEMPT_RT
+#ifdef CONFIG_ZEN_INTERACTIVE
+const_debug unsigned int sysctl_sched_nr_migrate = 64;
+#elif defined(CONFIG_PREEMPT_RT)
const_debug unsigned int sysctl_sched_nr_migrate = 8;
#else
const_debug unsigned int sysctl_sched_nr_migrate = 32;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a68482d66535588d0b8dd9b0738482fda17f2fb6..416cfec3cd0b7981cefb0c620e6cbaeaa553d200 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -67,8 +67,13 @@
*
* (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
*/
+#ifdef CONFIG_ZEN_INTERACTIVE
+unsigned int sysctl_sched_latency = 4000000ULL;
+static unsigned int normalized_sysctl_sched_latency = 4000000ULL;
+#else
unsigned int sysctl_sched_latency = 6000000ULL;
static unsigned int normalized_sysctl_sched_latency = 6000000ULL;
+#endif
/*
* The initial- and re-scaling of tunables is configurable
@@ -88,8 +93,13 @@ unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
*
* (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
*/
+#ifdef CONFIG_ZEN_INTERACTIVE
+unsigned int sysctl_sched_min_granularity = 400000ULL;
+static unsigned int normalized_sysctl_sched_min_granularity = 400000ULL;
+#else
unsigned int sysctl_sched_min_granularity = 750000ULL;
static unsigned int normalized_sysctl_sched_min_granularity = 750000ULL;
+#endif
/*
* Minimal preemption granularity for CPU-bound SCHED_IDLE tasks.
@@ -102,7 +112,11 @@ unsigned int sysctl_sched_idle_min_granularity = 750000ULL;
/*
* This value is kept at sysctl_sched_latency/sysctl_sched_min_granularity
*/
+#ifdef CONFIG_ZEN_INTERACTIVE
+static unsigned int sched_nr_latency = 10;
+#else
static unsigned int sched_nr_latency = 8;
+#endif
/*
* After fork, child runs first. If set to 0 (default) then
@@ -119,8 +133,13 @@ unsigned int sysctl_sched_child_runs_first __read_mostly;
*
* (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
*/
+#ifdef CONFIG_ZEN_INTERACTIVE
+unsigned int sysctl_sched_wakeup_granularity = 500000UL;
+static unsigned int normalized_sysctl_sched_wakeup_granularity = 500000UL;
+#else
unsigned int sysctl_sched_wakeup_granularity = 1000000UL;
static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
+#endif
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
@@ -173,8 +192,12 @@ int __weak arch_asym_cpu_priority(int cpu)
*
* (default: 5 msec, units: microseconds)
*/
+#ifdef CONFIG_ZEN_INTERACTIVE
+unsigned int sysctl_sched_cfs_bandwidth_slice = 3000UL;
+#else
unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
#endif
+#endif
static inline void update_load_add(struct load_weight *lw, unsigned long inc)
{
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