[v4,0/3] sched/fair: some fixes for asym_packing

Message ID 1547747049-6320-1-git-send-email-vincent.guittot@linaro.org
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  • sched/fair: some fixes for asym_packing
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Vincent Guittot Jan. 17, 2019, 5:44 p.m.
During the review of misfit task patchset, Morten and Valentin raised some
problems with the use of SD_ASYM_PACKING flag on asymmetric system like
hikey960 arm64 big/LITTLE platform. The study of the use cases has shown
some problems that can happen for every systems that use the flag.

The 3 patches fixes the problems raised for lmbench and the rt-app UC that
creates 2 tasks that start as small tasks and then become suddenly always
running tasks. (I can provide the rt-app json if needed)

Changes since v3:
- simplify imbalance computation 

Changes since v2:
- include other active balance reasons
- set imbalance to avg_load as suggested by Valentin

Changes since v1:
- rebase on tip/sched/core
- changes asym_active_balance() as suggested by Peter

Vincent Guittot (3):
  sched/fair: fix rounding issue for asym packing
  sched/fair: trigger asym_packing during idle load balance
  sched/fair: fix unnecessary increase of balance interval

 kernel/sched/fair.c | 44 ++++++++++++++++++++++++++++----------------
 1 file changed, 28 insertions(+), 16 deletions(-)