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* [PATCH 00/16] sched: Clean-ups and asymmetric cpu capacity support
@ 2016-05-23 10:58 Morten Rasmussen
  2016-05-23 10:58 ` [PATCH 01/16] sched: Fix power to capacity renaming in comment Morten Rasmussen
                   ` (15 more replies)
  0 siblings, 16 replies; 61+ messages in thread
From: Morten Rasmussen @ 2016-05-23 10:58 UTC (permalink / raw)
  To: peterz, mingo
  Cc: dietmar.eggemann, yuyang.du, vincent.guittot, mgalbraith,
	linux-kernel, Morten Rasmussen

Hi,

The scheduler is currently not doing much to help performance on systems with
asymmetric compute capacities (read ARM big.LITTLE). This series improves the
situation with a few tweaks mainly to the task wake-up path that considers
compute capacity at wake-up and not just whether a cpu is idle for these
systems. This gives us consistent, and potentially higher, throughput in
partially utilized scenarious. SMP behaviour and performance should be
unaffected.

Test 0:
	for i in `seq 1 10`; \
	       do sysbench --test=cpu --max-time=3 --num-threads=1 run; \
	       done \
	| awk '{if ($4=="events:") {print $5; sum +=$5; runs +=1}} \
	       END {print "Average events: " sum/runs}'

Target: ARM TC2 (2xA15+3xA7)

	(Higher is better)
tip:	Average events: 150.2
patch:	Average events: 217.9

Test 1:
	perf stat --null --repeat 10 -- \
	perf bench sched messaging -g 50 -l 5000

Target: Intel IVB-EP (2*10*2)

tip:	4.831538935 seconds time elapsed ( +-  1.58% )
patch:	4.839951382 seconds time elapsed ( +-  1.01% )

Target: ARM TC2 A7-only (3xA7) (-l 1000)

tip:	61.406552538 seconds time elapsed ( +-  0.12% )
patch:	61.589263159 seconds time elapsed ( +-  0.22% )

Active migration of tasks away from small capacity cpus isn't addressed
in this set although it is necessary for consistent throughput in other
scenarios on asymmetric cpu capacity systems.

Patch   1-4: Generic fixes and clean-ups.
Patch  5-13: Improve capacity awareness.
Patch 14-16: Arch features for arm to enable asymmetric capacity support.

Dietmar Eggemann (1):
  sched: Store maximum per-cpu capacity in root domain

Morten Rasmussen (15):
  sched: Fix power to capacity renaming in comment
  sched/fair: Consistent use of prev_cpu in wakeup path
  sched/fair: Disregard idle task wakee_flips in wake_wide
  sched/fair: Optimize find_idlest_cpu() when there is no choice
  sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag
  sched: Disable WAKE_AFFINE for asymmetric configurations
  sched: Make SD_BALANCE_WAKE a topology flag
  sched/fair: Let asymmetric cpu configurations balance at wake-up
  sched/fair: Compute task/cpu utilization at wake-up more correctly
  sched/fair: Consider spare capacity in find_idlest_group()
  sched: Add per-cpu max capacity to sched_group_capacity
  sched/fair: Avoid pulling tasks from non-overloaded higher capacity
    groups
  arm: Set SD_ASYM_CPUCAPACITY for big.LITTLE platforms
  arm: Set SD_BALANCE_WAKE flag for asymmetric capacity systems
  arm: Update arch_scale_cpu_capacity() to reflect change to define

 arch/arm/include/asm/topology.h |   5 +
 arch/arm/kernel/topology.c      |  25 ++++-
 include/linux/sched.h           |   3 +-
 kernel/sched/core.c             |  25 ++++-
 kernel/sched/fair.c             | 217 ++++++++++++++++++++++++++++++++++++----
 kernel/sched/sched.h            |   5 +-
 6 files changed, 250 insertions(+), 30 deletions(-)

-- 
1.9.1

^ permalink raw reply	[flat|nested] 61+ messages in thread

end of thread, other threads:[~2016-06-08 14:36 UTC | newest]

Thread overview: 61+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-05-23 10:58 [PATCH 00/16] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen
2016-05-23 10:58 ` [PATCH 01/16] sched: Fix power to capacity renaming in comment Morten Rasmussen
2016-05-23 10:58 ` [PATCH 02/16] sched/fair: Consistent use of prev_cpu in wakeup path Morten Rasmussen
2016-06-01 19:49   ` Peter Zijlstra
2016-05-23 10:58 ` [PATCH 03/16] sched/fair: Disregard idle task wakee_flips in wake_wide Morten Rasmussen
2016-05-23 11:12   ` Mike Galbraith
2016-05-23 12:00     ` Morten Rasmussen
2016-05-23 13:00       ` Mike Galbraith
2016-05-23 14:10         ` Morten Rasmussen
2016-05-23 15:42           ` Mike Galbraith
2016-05-23 23:17             ` Yuyang Du
2016-05-23 23:04       ` Yuyang Du
2016-06-01 19:57       ` Peter Zijlstra
2016-06-02  8:05         ` Peter Zijlstra
2016-06-07 12:08           ` Morten Rasmussen
2016-05-23 10:58 ` [PATCH 04/16] sched/fair: Optimize find_idlest_cpu() when there is no choice Morten Rasmussen
2016-05-24  6:29   ` Mike Galbraith
2016-05-24  8:05     ` Morten Rasmussen
2016-05-24  8:12       ` Mike Galbraith
2016-06-01 19:59   ` Peter Zijlstra
2016-06-07 14:25     ` Morten Rasmussen
2016-05-23 10:58 ` [PATCH 05/16] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Morten Rasmussen
2016-05-23 10:58 ` [PATCH 06/16] sched: Disable WAKE_AFFINE for asymmetric configurations Morten Rasmussen
2016-05-24  9:10   ` Vincent Guittot
2016-05-24 10:29     ` Morten Rasmussen
2016-05-24 12:12       ` Vincent Guittot
2016-05-24 13:16         ` Morten Rasmussen
2016-05-24 13:27           ` Vincent Guittot
2016-05-24 13:36             ` Morten Rasmussen
2016-05-24 13:52               ` Vincent Guittot
2016-05-24 15:02                 ` Morten Rasmussen
2016-05-24 15:53                   ` Vincent Guittot
2016-05-25  9:12                     ` Morten Rasmussen
2016-05-26  6:45                       ` Vincent Guittot
2016-06-07 16:50                         ` Morten Rasmussen
2016-05-23 10:58 ` [PATCH 07/16] sched: Make SD_BALANCE_WAKE a topology flag Morten Rasmussen
2016-05-24 23:52   ` Yuyang Du
2016-05-25  9:27     ` Morten Rasmussen
2016-06-01 20:18   ` Peter Zijlstra
2016-06-08  8:45     ` Morten Rasmussen
2016-05-23 10:58 ` [PATCH 08/16] sched: Store maximum per-cpu capacity in root domain Morten Rasmussen
2016-05-23 10:58 ` [PATCH 09/16] sched/fair: Let asymmetric cpu configurations balance at wake-up Morten Rasmussen
2016-05-24  0:04   ` Yuyang Du
2016-05-24  8:10     ` Morten Rasmussen
2016-05-24  7:03   ` Mike Galbraith
2016-05-24  7:15     ` Mike Galbraith
2016-05-25  6:57   ` Wanpeng Li
2016-05-25  9:49     ` Morten Rasmussen
2016-05-25 10:29       ` Wanpeng Li
2016-05-25 10:54         ` Morten Rasmussen
2016-05-25 11:18           ` Wanpeng Li
2016-06-02 14:21   ` Peter Zijlstra
2016-06-08 11:29     ` Morten Rasmussen
2016-06-08 14:36       ` Peter Zijlstra
2016-05-23 10:58 ` [PATCH 10/16] sched/fair: Compute task/cpu utilization at wake-up more correctly Morten Rasmussen
2016-05-23 10:58 ` [PATCH 11/16] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen
2016-05-23 10:58 ` [PATCH 12/16] sched: Add per-cpu max capacity to sched_group_capacity Morten Rasmussen
2016-05-23 10:58 ` [PATCH 13/16] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen
2016-05-23 10:58 ` [PATCH 14/16] arm: Set SD_ASYM_CPUCAPACITY for big.LITTLE platforms Morten Rasmussen
2016-05-23 10:58 ` [PATCH 15/16] arm: Set SD_BALANCE_WAKE flag for asymmetric capacity systems Morten Rasmussen
2016-05-23 10:58 ` [PATCH 16/16] arm: Update arch_scale_cpu_capacity() to reflect change to define Morten Rasmussen

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