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3e8c6c9aac
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Vincent Donnefort 3e8c6c9aac sched/fair: Remove task_util from effective utilization in feec() 
The energy estimation in find_energy_efficient_cpu() (feec()) relies on
the computation of the effective utilization for each CPU of a perf domain
(PD). This effective utilization is then used as an estimation of the busy
time for this pd. The function effective_cpu_util() which gives this value,
scales the utilization relative to IRQ pressure on the CPU to take into
account that the IRQ time is hidden from the task clock. The IRQ scaling is
as follow:

   effective_cpu_util = irq + (cpu_cap - irq)/cpu_cap * util

Where util is the sum of CFS/RT/DL utilization, cpu_cap the capacity of
the CPU and irq the IRQ avg time.

If now we take as an example a task placement which doesn't raise the OPP
on the candidate CPU, we can write the energy delta as:

  delta = OPPcost/cpu_cap * (effective_cpu_util(cpu_util + task_util) -
                             effective_cpu_util(cpu_util))
        = OPPcost/cpu_cap * (cpu_cap - irq)/cpu_cap * task_util

We end-up with an energy delta depending on the IRQ avg time, which is a
problem: first the time spent on IRQs by a CPU has no effect on the
additional energy that would be consumed by a task. Second, we don't want
to favour a CPU with a higher IRQ avg time value.

Nonetheless, we need to take the IRQ avg time into account. If a task
placement raises the PD's frequency, it will increase the energy cost for
the entire time where the CPU is busy. A solution is to only use
effective_cpu_util() with the CPU contribution part. The task contribution
is added separately and scaled according to prev_cpu's IRQ time.

No change for the FREQUENCY_UTIL component of the energy estimation. We
still want to get the actual frequency that would be selected after the
task placement.

Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://lkml.kernel.org/r/20220621090414.433602-7-vdonnefort@google.com
2022-06-28 09:17:47 +02:00
..
bpf bpf: Fix calling global functions from BPF_PROG_TYPE_EXT programs 2022-06-07 10:41:20 -07:00
cgroup Merge branch 'for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2022-05-25 11:47:25 -07:00
configs x86/configs: Add x86 debugging Kconfig fragment plus docs 2022-04-06 19:56:29 +02:00
debug Modules updates for v5.19-rc1 2022-05-26 17:13:43 -07:00
dma swiotlb: fix setting ->force_bounce 2022-06-02 07:17:59 +02:00
entry * Fix syzkaller NULL pointer dereference 2022-06-08 09:16:31 -07:00
events Two small perf updates: 2022-06-05 10:40:31 -07:00
futex drm for 5.19-rc1 2022-05-25 16:18:27 -07:00
gcov gcov: Remove compiler version check 2021-12-02 17:25:21 +09:00
irq Updates for interrupt core and drivers: 2022-05-23 16:58:49 -07:00
kcsan linux-kselftest-kunit-5.19-rc1 2022-05-25 11:32:53 -07:00
livepatch Livepatching changes for 5.19 2022-06-02 08:55:01 -07:00
locking sysctl changes for v5.19-rc1 2022-05-26 16:57:20 -07:00
module module: Fix prefix for module.sig_enforce module param 2022-06-02 12:44:33 -07:00
power cxl for 5.19 2022-05-27 21:24:19 -07:00
printk Revert "printk: wake up all waiters" 2022-05-27 13:04:46 +02:00
rcu sysctl changes for v5.19-rc1 2022-05-26 16:57:20 -07:00
sched sched/fair: Remove task_util from effective utilization in feec() 2022-06-28 09:17:47 +02:00
time While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
trace Networking fixes for 5.19-rc2, including fixes from bpf and netfilter. 2022-06-09 12:06:52 -07:00
.gitignore
acct.c kernel/acct: move acct sysctls to its own file 2022-04-06 13:43:44 -07:00
async.c Revert "module, async: async_synchronize_full() on module init iff async is used" 2022-02-03 11:20:34 -08:00
audit_fsnotify.c fsnotify: make allow_dups a property of the group 2022-04-25 14:37:18 +02:00
audit_tree.c audit: use fsnotify group lock helpers 2022-04-25 14:37:28 +02:00
audit_watch.c fsnotify: pass flags argument to fsnotify_alloc_group() 2022-04-25 14:37:12 +02:00
audit.c audit: improve audit queue handling when "audit=1" on cmdline 2022-01-25 13:22:51 -05:00
audit.h audit: log AUDIT_TIME_* records only from rules 2022-02-22 13:51:40 -05:00
auditfilter.c audit/stable-5.17 PR 20220110 2022-01-11 13:08:21 -08:00
auditsc.c audit,io_uring,io-wq: call __audit_uring_exit for dummy contexts 2022-05-17 15:03:36 -04:00
backtracetest.c
bounds.c
capability.c xfs: don't generate selinux audit messages for capability testing 2022-03-09 10:32:06 -08:00
cfi.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c Intel Trust Domain Extensions 2022-05-23 17:51:12 -07:00
crash_core.c Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
crash_dump.c
cred.c x86: Mark __invalid_creds() __noreturn 2022-03-15 10:32:44 +01:00
delayacct.c delayacct: track delays from write-protect copy 2022-06-01 15:55:25 -07:00
dma.c
exec_domain.c
exit.c ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
extable.c lkdtm: Really write into kernel text in WRITE_KERN 2022-02-16 23:25:12 +11:00
fail_function.c
fork.c This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
freezer.c
gen_kheaders.sh kheaders: Have cpio unconditionally replace files 2022-05-08 03:16:59 +09:00
groups.c
hung_task.c Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
iomem.c
irq_work.c irq_work: use kasan_record_aux_stack_noalloc() record callstack 2022-04-15 14:49:55 -07:00
jump_label.c
kallsyms.c ftrace: Add ftrace_lookup_symbols function 2022-05-10 14:42:06 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels" 2022-03-31 10:36:55 +02:00
kcov.c kcov: update pos before writing pc in trace function 2022-05-25 13:05:42 -07:00
kexec_core.c Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
kexec_elf.c
kexec_file.c RISC-V Patches for the 5.19 Merge Window, Part 1 2022-05-31 14:10:54 -07:00
kexec_internal.h
kexec.c
kheaders.c
kmod.c
kprobes.c tracing updates for 5.19: 2022-05-29 10:31:36 -07:00
ksysfs.c kernel/ksysfs.c: use helper macro __ATTR_RW 2022-03-23 19:00:33 -07:00
kthread.c kthread: unexport kthread_blkcg 2022-05-02 14:06:20 -06:00
latencytop.c latencytop: move sysctl to its own file 2022-04-21 11:40:59 -07:00
Makefile kernel: add platform_has() infrastructure 2022-06-06 08:06:00 +02:00
module_signature.c
notifier.c notifier: Add blocking/atomic_notifier_chain_register_unique_prio() 2022-05-19 19:30:30 +02:00
nsproxy.c
padata.c padata: replace cpumask_weight with cpumask_empty in padata.c 2022-01-31 11:21:46 +11:00
panic.c sysctl changes for v5.19-rc1 2022-05-26 16:57:20 -07:00
params.c kobject: remove kset from struct kset_uevent_ops callbacks 2021-12-28 11:26:18 +01:00
pid_namespace.c kernel: pid_namespace: use NULL instead of using plain integer as pointer 2022-04-29 14:38:00 -07:00
pid.c
platform-feature.c kernel: add platform_has() infrastructure 2022-06-06 08:06:00 +02:00
profile.c exit: Remove profile_handoff_task 2022-01-08 12:43:57 -06:00
ptrace.c While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
range.c
reboot.c kernel/reboot: Fix powering off using a non-syscall code paths 2022-06-07 19:42:31 +02:00
regset.c
relay.c relay: remove redundant assignment to pointer buf 2022-05-12 20:38:37 -07:00
resource_kunit.c
resource.c kernel/resource: fix kfree() of bootmem memory again 2022-03-23 19:00:35 -07:00
rseq.c rseq: Remove broken uapi field layout on 32-bit little endian 2022-02-02 13:11:34 +01:00
scftorture.c scftorture: Fix distribution of short handler delays 2022-04-11 17:07:29 -07:00
scs.c kasan, vmalloc: only tag normal vmalloc allocations 2022-03-24 19:06:48 -07:00
seccomp.c seccomp: Add wait_killable semantic to seccomp user notifier 2022-05-03 14:11:58 -07:00
signal.c While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
smp.c Scheduler changes in this cycle were: 2022-05-24 11:11:13 -07:00
smpboot.c cpu/hotplug: Allow the CPU in CPU_UP_PREPARE state to be brought up again. 2022-04-12 14:13:01 +02:00
smpboot.h
softirq.c smp: Make softirq handling RT safe in flush_smp_call_function_queue() 2022-05-01 10:03:43 +02:00
stackleak.c stackleak: add on/off stack variants 2022-05-08 01:33:09 -07:00
stacktrace.c uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
static_call_inline.c static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
static_call.c static_call: Don't make __static_call_return0 static 2022-04-05 09:59:38 +02:00
stop_machine.c Scheduler changes in this cycle were: 2022-05-24 11:11:13 -07:00
sys_ni.c mm/mempolicy: wire up syscall set_mempolicy_home_node 2022-01-15 16:30:30 +02:00
sys.c arm64/sme: Implement vector length configuration prctl()s 2022-04-22 18:50:54 +01:00
sysctl-test.c
sysctl.c sysctl changes for v5.19-rc1 2022-05-26 16:57:20 -07:00
task_work.c task_work: allow TWA_SIGNAL without a rescheduling IPI 2022-04-30 08:39:32 -06:00
taskstats.c kernel: make taskstats available from all net namespaces 2022-04-29 14:38:03 -07:00
torture.c torture: Wake up kthreads after storing task_struct pointer 2022-02-01 17:24:39 -08:00
tracepoint.c
tsacct.c taskstats: version 12 with thread group and exe info 2022-04-29 14:38:03 -07:00
ucount.c ucounts: Handle wrapping in is_ucounts_overlimit 2022-02-17 09:11:57 -06:00
uid16.c
uid16.h
umh.c kthread: Don't allocate kthread_struct for init and umh 2022-05-06 14:49:44 -05:00
up.c
user_namespace.c ucounts: Fix systemd LimitNPROC with private users regression 2022-02-25 10:40:14 -06:00
user-return-notifier.c
user.c
usermode_driver.c blob_to_mnt(): kern_unmount() is needed to undo kern_mount() 2022-05-19 23:25:47 -04:00
utsname_sysctl.c
utsname.c
watch_queue.c watch_queue: Free the page array when watch_queue is dismantled 2022-04-02 10:37:39 -07:00
watchdog_hld.c printk: add functions to prefer direct printing 2022-04-22 21:30:58 +02:00
watchdog.c Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
workqueue_internal.h
workqueue.c workqueue: Wrap flush_workqueue() using a macro 2022-06-07 07:07:14 -10:00