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author | Vincent Guittot <vincent.guittot@linaro.org> | 2019-10-22 14:53:15 +0200 |
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committer | Vincent Guittot <vincent.guittot@linaro.org> | 2019-10-22 18:41:05 +0200 |
commit | 5de07d127290c0822309a31bf250c212802f62e8 (patch) | |
tree | a85dfdcb3895e63517a2f5a05df68faa7c4db6e3 /tools | |
parent | 04dfd1bca609c5d1c8b7e073f723e4efb3a38fd0 (diff) |
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>
Diffstat (limited to 'tools')
0 files changed, 0 insertions, 0 deletions