mirror_ubuntu-kernels/kernel/sched
Vincent Guittot 9c0b4bb7f6 sched/cpufreq: Rework schedutil governor performance estimation
The current method to take into account uclamp hints when estimating the
target frequency can end in a situation where the selected target
frequency is finally higher than uclamp hints, whereas there are no real
needs. Such cases mainly happen because we are currently mixing the
traditional scheduler utilization signal with the uclamp performance
hints. By adding these 2 metrics, we loose an important information when
it comes to select the target frequency, and we have to make some
assumptions which can't fit all cases.

Rework the interface between the scheduler and schedutil governor in order
to propagate all information down to the cpufreq governor.

effective_cpu_util() interface changes and now returns the actual
utilization of the CPU with 2 optional inputs:

- The minimum performance for this CPU; typically the capacity to handle
  the deadline task and the interrupt pressure. But also uclamp_min
  request when available.

- The maximum targeting performance for this CPU which reflects the
  maximum level that we would like to not exceed. By default it will be
  the CPU capacity but can be reduced because of some performance hints
  set with uclamp. The value can be lower than actual utilization and/or
  min performance level.

A new sugov_effective_cpu_perf() interface is also available to compute
the final performance level that is targeted for the CPU, after applying
some cpufreq headroom and taking into account all inputs.

With these 2 functions, schedutil is now able to decide when it must go
above uclamp hints. It now also has a generic way to get the min
performance level.

The dependency between energy model and cpufreq governor and its headroom
policy doesn't exist anymore.

eenv_pd_max_util() asks schedutil for the targeted performance after
applying the impact of the waking task.

[ mingo: Refined the changelog & C comments. ]

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20231122133904.446032-2-vincent.guittot@linaro.org
2023-11-23 11:32:01 +01:00
..
autogroup.c sched/all: Change all BUG_ON() instances in the scheduler to WARN_ON_ONCE() 2022-08-12 11:25:10 +02:00
autogroup.h sched/headers: Add header guard to kernel/sched/stats.h and kernel/sched/autogroup.h 2022-02-23 08:22:00 +01:00
build_policy.c sched: Fix missing prototype warnings 2022-05-01 10:03:43 +02:00
build_utility.c sched/headers: Remove duplicate header inclusions 2023-10-03 21:27:55 +02:00
clock.c Locking changes for v6.5: 2023-06-27 14:14:30 -07:00
completion.c sched: add a few helpers to wake up tasks on the current cpu 2023-07-17 16:08:08 -07:00
core_sched.c sched: Rename task_running() to task_on_cpu() 2022-09-07 21:53:47 +02:00
core.c sched/cpufreq: Rework schedutil governor performance estimation 2023-11-23 11:32:01 +01:00
cpuacct.c Merge branch 'sched/fast-headers' into sched/core 2022-03-15 09:05:05 +01:00
cpudeadline.c sched/topology: Consolidate and clean up access to a CPU's max compute capacity 2023-10-09 12:59:48 +02:00
cpudeadline.h
cpufreq_schedutil.c sched/cpufreq: Rework schedutil governor performance estimation 2023-11-23 11:32:01 +01:00
cpufreq.c sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
cpupri.c sched/rt: Fix live lock between select_fallback_rq() and RT push 2023-09-28 22:58:13 +02:00
cpupri.h sched/cpupri: Add CPUPRI_HIGHER 2020-10-29 11:00:30 +01:00
cputime.c cputime: remove cputime_to_nsecs fallback 2022-12-27 12:52:17 +01:00
deadline.c sched/deadline: Introduce deadline servers 2023-11-15 09:57:51 +01:00
debug.c sched/eevdf: Sort the rbtree by virtual deadline 2023-11-15 09:57:47 +01:00
fair.c sched/cpufreq: Rework schedutil governor performance estimation 2023-11-23 11:32:01 +01:00
features.h sched/fair: Remove SIS_PROP 2023-10-24 10:38:44 +02:00
idle.c sched/cpuidle: Comment about timers requirements VS idle handler 2023-11-15 09:57:51 +01:00
isolation.c sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
loadavg.c sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
Makefile sched/headers: Introduce kernel/sched/build_policy.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
membarrier.c sched/membarrier: Introduce MEMBARRIER_CMD_GET_REGISTRATIONS 2023-01-07 11:29:29 +01:00
pelt.c sched: Make PELT acronym definition searchable 2023-10-13 09:56:30 +02:00
pelt.h sched/fair: Decay task PELT values during wakeup migration 2022-06-28 09:17:46 +02:00
psi.c sched/psi: Update poll => rtpoll in relevant comments 2023-10-16 13:42:49 +02:00
rt.c sched: Unify runtime accounting across classes 2023-11-15 09:57:48 +01:00
sched-pelt.h sched/fair: Fix "runnable_avg_yN_inv" not used warnings 2019-06-17 12:15:58 +02:00
sched.h sched/cpufreq: Rework schedutil governor performance estimation 2023-11-23 11:32:01 +01:00
smp.h sched, smp: Trace smp callback causing an IPI 2023-03-24 11:01:29 +01:00
stats.c sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c files there 2022-02-23 10:58:33 +01:00
stats.h sched/psi: Use task->psi_flags to clear in CPU migration 2022-10-30 10:12:15 +01:00
stop_task.c sched: Unify runtime accounting across classes 2023-11-15 09:57:48 +01:00
swait.c sched: add a few helpers to wake up tasks on the current cpu 2023-07-17 16:08:08 -07:00
topology.c sched/fair: Scan cluster before scanning LLC in wake-up path 2023-10-24 10:38:43 +02:00
wait_bit.c wait_on_bit: add an acquire memory barrier 2022-08-26 09:30:25 -07:00
wait.c sched: remove wait bookmarks 2023-10-18 14:34:18 -07:00