linux/kernel/sched
Valentin Schneider b9a7b88316 sched/fair: Skip LLC NOHZ logic for asymmetric systems
The LLC NOHZ condition will become true as soon as >=2 CPUs in a
single LLC domain are busy. On big.LITTLE systems, this translates to
two or more CPUs of a "cluster" (big or LITTLE) being busy.

Issuing a NOHZ kick in these conditions isn't desired for asymmetric
systems, as if the busy CPUs can provide enough compute capacity to
the running tasks, then we can leave the NOHZ CPUs in peace.

Skip the LLC NOHZ condition for asymmetric systems, and rely on
nr_running & capacity checks to trigger NOHZ kicks when the system
actually needs them.

Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dietmar.Eggemann@arm.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: vincent.guittot@linaro.org
Link: https://lkml.kernel.org/r/20190211175946.4961-4-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-03-19 12:06:15 +01:00
..
autogroup.c sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[] 2018-05-05 08:34:42 +02:00
autogroup.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
clock.c sched/clock: Disable interrupts when calling generic_sched_clock_init() 2018-07-30 19:33:35 +02:00
completion.c sched/Documentation: Update wake_up() & co. memory-barrier guarantees 2018-07-17 09:30:34 +02:00
core.c sched/core: Fix buffer overflow in cgroup2 property cpu.max 2019-03-19 12:06:15 +01:00
cpuacct.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpudeadline.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpudeadline.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpufreq_schedutil.c sched/cpufreq: Fix 32-bit math overflow 2019-03-19 12:06:11 +01:00
cpufreq.c sched/cpufreq: Add the SPDX tags 2018-12-11 11:35:25 +01:00
cpupri.c sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cpupri.h sched/headers: Simplify and clean up header usage in the scheduler 2018-03-04 12:39:29 +01:00
cputime.c sched: Fix various typos in comments 2018-12-03 11:55:42 +01:00
deadline.c sched/fair: Update scale invariance of PELT 2019-02-04 09:13:21 +01:00
debug.c sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK 2019-02-04 09:13:21 +01:00
fair.c sched/fair: Skip LLC NOHZ logic for asymmetric systems 2019-03-19 12:06:15 +01:00
features.h sched/fair: Disable LB_BIAS by default 2018-10-02 09:45:01 +02:00
idle.c x86/stackprotector: Remove the call to boot_init_stack_canary() from cpu_startup_entry() 2018-10-22 04:07:24 +02:00
isolation.c sched/fair: Use non-atomic cpumask_{set,clear}_cpu() 2019-02-13 08:34:13 +01:00
loadavg.c sched: loadavg: make calc_load_n() public 2018-10-26 16:26:32 -07:00
Makefile psi: pressure stall information for CPU, memory, and IO 2018-10-26 16:26:32 -07:00
membarrier.c sched/membarrier: synchronize_sched() with synchronize_rcu() 2018-11-27 09:21:43 -08:00
pelt.c sched/fair: Update scale invariance of PELT 2019-02-04 09:13:21 +01:00
pelt.h sched/fair: Update scale invariance of PELT 2019-02-04 09:13:21 +01:00
psi.c psi: fix aggregation idle shut-off 2019-02-01 15:46:23 -08:00
rt.c sched/fair: Update scale invariance of PELT 2019-02-04 09:13:21 +01:00
sched-pelt.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sched.h sched/fair: Simplify post_init_entity_util_avg() by calling it with a task_struct pointer argument 2019-02-11 08:02:14 +01:00
stats.c proc: introduce proc_create_seq{,_data} 2018-05-16 07:23:35 +02:00
stats.h psi: make disabling/enabling easier for vendor kernels 2018-11-30 14:56:14 -08:00
stop_task.c sched: Clean up and harmonize the coding style of the scheduler code base 2018-03-03 15:50:21 +01:00
swait.c kernel/sched/: remove caller signal_pending branch predictions 2019-01-04 13:13:48 -08:00
topology.c sched/topology: Fix percpu data types in struct sd_data & struct s_data 2019-02-11 08:02:15 +01:00
wait_bit.c sched/wait: Improve __var_waitqueue() code generation 2018-03-20 08:23:25 +01:00
wait.c kernel/sched/: remove caller signal_pending branch predictions 2019-01-04 13:13:48 -08:00