Vincent Guittot 10a35e6812 sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity ...

util_est is mainly meant to be a lower-bound for tasks utilization.
That's why task_util_est() returns the actual util_avg when it's higher
than the estimated utilization.

With new invaraince signal and without any special check on samples
collection, if a task is limited because of thermal capping for
example, we could end up overestimating its utilization and thus
perhaps generating an unwanted frequency spike when the capping is
relaxed... and (even worst) it will take some more activations for the
estimated utilization to converge back to the actual utilization.

Since we cannot easily know if there is idle time in a CPU when a task
completes an activation with a utilization higher then the CPU capacity,
we skip the sampling when utilization is higher than CPU's capacity.

Suggested-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: pjt@google.com
Cc: pkondeti@codeaurora.org
Cc: quentin.perret@arm.com
Cc: rjw@rjwysocki.net
Cc: srinivas.pandruvada@linux.intel.com
Cc: thara.gopinath@linaro.org
Link: https://lkml.kernel.org/r/1548257214-13745-4-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2019-02-04 09:13:21 +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/fair: Update scale invariance of PELT

2019-02-04 09:13:21 +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

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-12-26 14:56:10 -08:00

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

jump_label: move 'asm goto' support test to Kconfig

2019-01-06 09:46:51 +09:00

fair.c

sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity

2019-02-04 09:13:21 +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: Fix various typos in comments

2018-12-03 11:55:42 +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: make disabling/enabling easier for vendor kernels

2018-11-30 14:56:14 -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/pelt: Skip updating util_est when utilization is higher than CPU's capacity

2019-02-04 09:13:21 +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/core: Give DCE a fighting chance

2019-01-27 12:29:37 +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