linux/kernel
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
..
bpf bpf: Fix syscall's stackmap lookup potential deadlock 2019-01-31 23:18:21 +01:00
cgroup Merge branch 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2018-12-29 10:57:20 -08:00
configs kvm_config: add CONFIG_VIRTIO_MENU 2018-10-24 20:55:56 -04:00
debug kdb: use bool for binary state indicators 2018-12-30 08:31:52 +00:00
dma swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit 2019-01-16 09:59:17 -05:00
events perf/core: Don't WARN() for impossible ring-buffer sizes 2019-02-04 08:45:25 +01:00
gcov
irq genirq/irqdesc: Fix double increment in alloc_descs() 2019-01-18 00:43:09 +01:00
livepatch livepatch: Replace synchronize_sched() with synchronize_rcu() 2018-12-01 12:38:50 -08:00
locking futex: Handle early deadlock return correctly 2019-02-08 13:00:36 +01:00
power mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
printk Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
rcu rcutorture: Don't do busted forward-progress testing 2018-12-01 12:45:42 -08:00
sched sched/fair: Skip LLC NOHZ logic for asymmetric systems 2019-03-19 12:06:15 +01:00
time posix-cpu-timers: Unbreak timer rearming 2019-01-15 16:34:37 +01:00
trace Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-02-08 11:21:54 -08:00
.gitignore
acct.c
async.c
audit.c audit: remove duplicated include from audit.c 2018-12-14 12:09:30 -05:00
audit.h audit: use current whenever possible 2018-11-26 18:41:21 -05:00
audit_fsnotify.c audit: minimize our use of audit_log_format() 2018-11-26 18:40:00 -05:00
audit_tree.c audit: minimize our use of audit_log_format() 2018-11-26 18:40:00 -05:00
audit_watch.c audit: minimize our use of audit_log_format() 2018-11-26 18:40:00 -05:00
auditfilter.c
auditsc.c audit: use current whenever possible 2018-11-26 18:41:21 -05:00
backtracetest.c
bounds.c kbuild: fix kernel/bounds.c 'W=1' warning 2018-10-31 08:54:14 -07:00
capability.c
compat.c make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
configs.c
context_tracking.c
cpu.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-01-30 19:27:00 +01:00
cpu_pm.c
crash_core.c kernel/crash_core.c: print timestamp using time64_t 2018-08-22 10:52:47 -07:00
crash_dump.c
cred.c cred: export get_task_cred(). 2018-12-19 13:52:44 -05:00
delayacct.c delayacct: track delays from thrashing cache pages 2018-10-26 16:26:32 -07:00
dma.c
elfcore.c
exec_domain.c
exit.c kernel/exit.c: release ptraced tasks before zap_pid_ns_processes 2019-02-01 15:46:23 -08:00
extable.c
fail_function.c kernel/fail_function.c: remove meaningless null pointer check before debugfs_remove_recursive 2018-10-31 08:54:12 -07:00
fork.c sched/core: Convert task_struct.stack_refcount to refcount_t 2019-02-04 08:53:56 +01:00
freezer.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
futex.c futex: Handle early deadlock return correctly 2019-02-08 13:00:36 +01:00
groups.c
hung_task.c kernel/hung_task.c: break RCU locks based on jiffies 2019-01-04 13:13:45 -08:00
iomem.c
irq_work.c
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
kallsyms.c kallsyms: reduce size a little on 64-bit 2018-09-10 22:54:33 +09:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt kconfig: warn no new line at end of file 2018-12-15 17:44:35 +09:00
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-01-04 13:13:47 -08:00
kexec.c kexec: add call to LSM hook in original kexec_load syscall 2018-07-16 12:31:57 -07:00
kexec_core.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
kexec_file.c kexec_file: kexec_walk_memblock() only walks a dedicated region at kdump 2018-12-06 14:38:50 +00:00
kexec_internal.h
kmod.c
kprobes.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-12-26 14:45:18 -08:00
ksysfs.c
kthread.c kthread: Do not use TIMER_IRQSAFE 2019-02-28 11:18:38 +01:00
latencytop.c
Makefile kbuild: change filechk to surround the given command with { } 2019-01-06 09:46:51 +09:00
memremap.c mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm 2018-12-28 12:11:52 -08:00
module-internal.h
module.c jump_label: move 'asm goto' support test to Kconfig 2019-01-06 09:46:51 +09:00
module_signing.c modsign: use all trusted keys to verify module signature 2018-11-07 14:41:41 +01:00
notifier.c
nsproxy.c
padata.c padata: clean an indentation issue, remove extraneous space 2018-11-16 14:11:04 +08:00
panic.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
params.c
pid.c Fix failure path in alloc_pid() 2018-12-28 12:42:30 -08:00
pid_namespace.c signal: Use group_send_sig_info to kill all processes in a pid namespace 2018-09-16 16:08:25 +02:00
profile.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
ptrace.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
range.c
reboot.c kernel/reboot.c: export pm_power_off_prepare 2018-09-11 16:13:24 +01:00
relay.c relay: check return of create_buf_file() properly 2019-01-31 14:01:48 +01:00
resource.c kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable 2018-12-28 12:11:49 -08:00
rseq.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
seccomp.c seccomp: fix UAF in user-trap code 2019-01-15 09:43:12 -08:00
signal.c signal: Better detection of synchronous signals 2019-02-07 09:00:36 -06:00
smp.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-01-30 19:27:00 +01:00
smpboot.c
smpboot.h
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-25 11:43:47 -07:00
stackleak.c stackleak: Mark stackleak_track_stack() as notrace 2018-12-05 19:31:44 -08:00
stacktrace.c
stop_machine.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
sys.c kernel/sys.c: Clarify that UNAME26 does not generate unique versions anymore 2019-01-14 10:38:03 +12:00
sys_ni.c y2038: socket: Add compat_sys_recvmmsg_time64 2018-12-18 16:13:04 +01:00
sysctl.c sched/topology: Introduce a sysctl for Energy Aware Scheduling 2019-01-27 12:29:37 +01:00
sysctl_binary.c kernel/sysctl: add panic_print into sysctl 2019-01-04 13:13:47 -08:00
task_work.c
taskstats.c
test_kprobes.c
torture.c torture: Remove unnecessary "ret" variables 2018-12-01 12:45:35 -08:00
tracepoint.c tracing: Replace synchronize_sched() and call_rcu_sched() 2018-11-27 09:21:41 -08:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c umh: add exit routine for UMH process 2019-01-11 18:05:40 -08:00
up.c smp,cpumask: introduce on_each_cpu_cond_mask 2018-10-09 16:51:11 +02:00
user-return-notifier.c
user.c userns: use irqsave variant of refcount_dec_and_lock() 2018-08-22 10:52:47 -07:00
user_namespace.c userns: also map extents in the reverse map to kernel IDs 2018-11-07 23:51:16 -06:00
utsname.c
utsname_sysctl.c sys: don't hold uts_sem while accessing userspace memory 2018-08-11 02:05:53 -05:00
watchdog.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
watchdog_hld.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
workqueue.c psi: fix aggregation idle shut-off 2019-02-01 15:46:23 -08:00
workqueue_internal.h psi: fix aggregation idle shut-off 2019-02-01 15:46:23 -08:00