sched/fair: fix rework of find_idlest_group()sched-rework-load_balance-v4

The task, for which the scheduler looks for the idlest group of CPUs, must
be discounted from all statistics in order to get a fair comparison
between groups. This includes utilization, load, nr_running and idle_cpus.

Such unfairness can be easily highlighted with the unixbench execl 1 task.
This test continuously call execve() and the scheduler looks for the idlest
group/CPU on which it should place the task. Because the task runs on the
local group/CPU, the latter seems already busy even if there is nothing
else running on it. As a result, the scheduler will always select another
group/CPU than the local one.

Fixes: 57abff067a08 ("sched/fair: Rework find_idlest_group()")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

0 files changed, 0 insertions, 0 deletions