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| author | Peter Zijlstra <peterz@infradead.org> | 2024-10-04 14:46:58 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-11-05 12:55:38 +0100 |
| commit | 7c70cb94d29cd325fabe4a818c18613e3b9919a1 (patch) | |
| tree | 2c4d6b58f7e284778060e2aff70db2b87d7a977c /kernel/sched/debug.c | |
| parent | 26baa1f1c4bdc34b8d698c1900b407d863ad0e69 (diff) | |
| download | linux-7c70cb94d29cd325fabe4a818c18613e3b9919a1.tar.gz linux-7c70cb94d29cd325fabe4a818c18613e3b9919a1.tar.bz2 linux-7c70cb94d29cd325fabe4a818c18613e3b9919a1.zip | |
sched: Add Lazy preemption model
Change fair to use resched_curr_lazy(), which, when the lazy
preemption model is selected, will set TIF_NEED_RESCHED_LAZY.
This LAZY bit will be promoted to the full NEED_RESCHED bit on tick.
As such, the average delay between setting LAZY and actually
rescheduling will be TICK_NSEC/2.
In short, Lazy preemption will delay preemption for fair class but
will function as Full preemption for all the other classes, most
notably the realtime (RR/FIFO/DEADLINE) classes.
The goal is to bridge the performance gap with Voluntary, such that we
might eventually remove that option entirely.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org
Diffstat (limited to 'kernel/sched/debug.c')
| -rw-r--r-- | kernel/sched/debug.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index f4035c7a0fa1..44a49f90b05f 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -245,11 +245,12 @@ static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf, static int sched_dynamic_show(struct seq_file *m, void *v) { static const char * preempt_modes[] = { - "none", "voluntary", "full" + "none", "voluntary", "full", "lazy", }; + int j = ARRAY_SIZE(preempt_modes) - !IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY); int i; - for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) { + for (i = 0; i < j; i++) { if (preempt_dynamic_mode == i) seq_puts(m, "("); seq_puts(m, preempt_modes[i]); |