105 lines
3.6 KiB
Diff
105 lines
3.6 KiB
Diff
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From 44a6d7ca11b601b34724dc41e086576499a096bd Mon Sep 17 00:00:00 2001
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From: "Jan Alexander Steffens (heftig)" <heftig@archlinux.org>
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Date: Tue, 31 Oct 2023 19:03:10 +0100
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Subject: ZEN: INTERACTIVE: Tune EEVDF for interactivity
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5.7:
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Take "sysctl_sched_nr_migrate" tune from early XanMod builds of 128. As
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of 5.7, XanMod uses 256 but that may affect applications that require
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timely response to IRQs.
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5.15:
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Per [a comment][1] on our ZEN INTERACTIVE commit, reducing the cost of
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migration causes the system less responsive under high load. Most
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likely the combination of reduced migration cost + the higher number of
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tasks that can be migrated at once contributes to this.
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To better handle this situation, restore the mainline migration cost
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value and also reduce the max number of tasks that can be migrated in
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batch from 128 to 64.
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If this doesn't help, we'll restore the reduced migration cost and keep
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total number of tasks that can be migrated at once to 32.
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[1]: https://github.com/zen-kernel/zen-kernel/commit/be5ba234ca0a5aabe74bfc7e1f636f085bd3823c#commitcomment-63159674
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6.6:
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Port the tuning to EEVDF, which removed a couple of settings.
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6.7:
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Instead of increasing the number of tasks that migrate at once, migrate
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the amount acceptable for PREEMPT_RT, but reduce the cost so migrations
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occur more often.
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This should make CFS/EEVDF behave more like out-of-tree schedulers that
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aggressively use idle cores to reduce latency, but without the jank
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caused by rebalancing too many tasks at once.
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---
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init/Kconfig | 7 +++++++
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kernel/sched/fair.c | 13 +++++++++++++
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kernel/sched/sched.h | 2 +-
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3 files changed, 21 insertions(+), 1 deletion(-)
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--- a/init/Kconfig
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+++ b/init/Kconfig
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@@ -150,6 +150,13 @@ config ZEN_INTERACTIVE
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Background-reclaim hugepages...: no -> yes
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MG-LRU minimum cache TTL.......: 0 -> 1000 ms
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+ --- EEVDF CPU Scheduler --------------------------------
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+
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+ Minimal granularity............: 0.75 -> 0.4 ms
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+ Migration cost.................: 0.5 -> 0.25 ms
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+ Bandwidth slice size...........: 5 -> 3 ms
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+ Task rebalancing threshold.....: 32 -> 8
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+
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config BROKEN
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bool
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--- a/kernel/sched/fair.c
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+++ b/kernel/sched/fair.c
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@@ -73,10 +73,19 @@ unsigned int sysctl_sched_tunable_scalin
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*
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* (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds)
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*/
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+#ifdef CONFIG_ZEN_INTERACTIVE
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+unsigned int sysctl_sched_base_slice = 400000ULL;
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+static unsigned int normalized_sysctl_sched_base_slice = 400000ULL;
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+#else
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unsigned int sysctl_sched_base_slice = 750000ULL;
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static unsigned int normalized_sysctl_sched_base_slice = 750000ULL;
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+#endif
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+#ifdef CONFIG_ZEN_INTERACTIVE
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+const_debug unsigned int sysctl_sched_migration_cost = 250000UL;
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+#else
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const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
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+#endif
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static int __init setup_sched_thermal_decay_shift(char *str)
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{
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@@ -121,8 +130,12 @@ int __weak arch_asym_cpu_priority(int cp
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*
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* (default: 5 msec, units: microseconds)
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*/
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+#ifdef CONFIG_ZEN_INTERACTIVE
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+static unsigned int sysctl_sched_cfs_bandwidth_slice = 3000UL;
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+#else
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static unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
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#endif
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+#endif
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#ifdef CONFIG_NUMA_BALANCING
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/* Restrict the NUMA promotion throughput (MB/s) for each target node. */
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--- a/kernel/sched/sched.h
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+++ b/kernel/sched/sched.h
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@@ -2591,7 +2591,7 @@ extern void deactivate_task(struct rq *r
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extern void wakeup_preempt(struct rq *rq, struct task_struct *p, int flags);
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-#ifdef CONFIG_PREEMPT_RT
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+#if defined(CONFIG_PREEMPT_RT) || defined(CONFIG_ZEN_INTERACTIVE)
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# define SCHED_NR_MIGRATE_BREAK 8
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#else
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# define SCHED_NR_MIGRATE_BREAK 32
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