From db713def08c043acdc63a9ce1989cc86c3ba13a4 Mon Sep 17 00:00:00 2001
From: Masahito S <firelzrd@gmail.com>
Date: Tue, 18 Apr 2023 02:02:43 +0900
Subject: [PATCH] constgran v2 for cachy sched: Make latency / granularity
 constant tunable_scaling = 1 (logarithmic) -> 0 (constant) latency_ns =
 variable 6-24ms -> constant 12.8ms min_granularity_ns = variable 0.75-3ms ->
 constant 1.6ms wakeup_granularity_ns = variable 1-4ms -> constant 9.6ms

---
 kernel/sched/fair.c | 51 +++++++++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 86a988c83..2667d5cee 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -67,15 +67,17 @@
  * (to see the precise effective timeslice length of your workload,
  *  run vmstat and monitor the context-switches (cs) field)
  *
- * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
+ * (BORE default: 12.8ms constant, units: nanoseconds)
+ * (CFS  default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
  */
-#ifdef CONFIG_CACHY
-unsigned int sysctl_sched_latency			= 3000000ULL;
-static unsigned int normalized_sysctl_sched_latency	= 3000000ULL;
-#else
+#ifdef CONFIG_SCHED_BORE
+unsigned int sysctl_sched_latency			= 12800000ULL;
+static unsigned int normalized_sysctl_sched_latency	= 12800000ULL;
+#else // CONFIG_SCHED_BORE
 unsigned int sysctl_sched_latency			= 6000000ULL;
 static unsigned int normalized_sysctl_sched_latency	= 6000000ULL;
-#endif
+#endif // CONFIG_SCHED_BORE
+
 /*
  * The initial- and re-scaling of tunables is configurable
  *
@@ -85,22 +87,28 @@ static unsigned int normalized_sysctl_sched_latency	= 6000000ULL;
  *   SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
  *   SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
  *
- * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ * (BORE default SCHED_TUNABLESCALING_NONE = *1 constant)
+ * (CFS  default SCHED_TUNABLESCALING_LOG  = *(1+ilog(ncpus))
  */
+#ifdef CONFIG_SCHED_BORE
+unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
+#else // CONFIG_SCHED_BORE
 unsigned int sysctl_sched_tunable_scaling = SCHED_TUNABLESCALING_LOG;
+#endif // CONFIG_SCHED_BORE
 
 /*
  * Minimal preemption granularity for CPU-bound tasks:
  *
- * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ * (BORE default: 1.6 msec constant, units: nanoseconds)
+ * (CFS  default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
  */
-#ifdef CONFIG_CACHY
-unsigned int sysctl_sched_min_granularity			= 400000ULL;
-static unsigned int normalized_sysctl_sched_min_granularity	= 400000ULL;
-#else
+#ifdef CONFIG_SCHED_BORE
+unsigned int sysctl_sched_min_granularity			= 1600000ULL;
+static unsigned int normalized_sysctl_sched_min_granularity	= 1600000ULL;
+#else // CONFIG_SCHED_BORE
 unsigned int sysctl_sched_min_granularity			= 750000ULL;
 static unsigned int normalized_sysctl_sched_min_granularity	= 750000ULL;
-#endif
+#endif // CONFIG_SCHED_BORE
 
 /*
  * Minimal preemption granularity for CPU-bound SCHED_IDLE tasks.
@@ -128,15 +136,16 @@ unsigned int sysctl_sched_child_runs_first __read_mostly;
  * and reduces their over-scheduling. Synchronous workloads will still
  * have immediate wakeup/sleep latencies.
  *
- * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
+ * (BORE default: 9.6 msec constant, units: nanoseconds)
+ * (CFS  default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
  */
-#ifdef CONFIG_CACHY
-unsigned int sysctl_sched_wakeup_granularity			= 500000UL;
-static unsigned int normalized_sysctl_sched_wakeup_granularity	= 500000UL;
-#else
+#ifdef CONFIG_SCHED_BORE
+unsigned int sysctl_sched_wakeup_granularity			= 9600000UL;
+static unsigned int normalized_sysctl_sched_wakeup_granularity	= 9600000UL;
+#else // CONFIG_SCHED_BORE
 unsigned int sysctl_sched_wakeup_granularity			= 1000000UL;
 static unsigned int normalized_sysctl_sched_wakeup_granularity	= 1000000UL;
-#endif
+#endif // CONFIG_SCHED_BORE
 
 const_debug unsigned int sysctl_sched_migration_cost	= 500000UL;
 
@@ -189,12 +198,8 @@ int __weak arch_asym_cpu_priority(int cpu)
  *
  * (default: 5 msec, units: microseconds)
  */
-#ifdef CONFIG_CACHY
-static unsigned int sysctl_sched_cfs_bandwidth_slice		= 3000UL;
-#else
 static unsigned int sysctl_sched_cfs_bandwidth_slice		= 5000UL;
 #endif
-#endif
 
 #ifdef CONFIG_NUMA_BALANCING
 /* Restrict the NUMA promotion throughput (MB/s) for each target node. */
-- 
2.25.1