[PATCH v3 0/3] sched/fair: some fixes for asym_packing

From: Vincent Guittot
Date: Thu Dec 20 2018 - 02:55:54 EST

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 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(-)