Re: [PATCH 3/4] sched: introduce synchronized idle injection

Peter Zijlstra
2015-11-23T18:07:16Z

On Mon, Nov 23, 2015 at 05:56:44PM +0000, Javi Merino wrote:
> I've tested this series on Juno (2xCortex-A57 4xCortex-A53). If you
> idle inject for 50% of the time, when I run 6 busy loops the scheduler
> sometimes keeps two of them in the same cpu while the another cpu is
> completely idle. Without idle injection the scheduler does the
> sensible thing: put one busy loop in each CPU. I'm running systemd
> and this only happens with CONFIG_SCHED_AUTOGROUP=y. If I unset
> CONFIG_SCHED_AUTOGROUP, the tasks are spread across all cpus as usual.

That's not a plus for this patch though; but a bug report against
AUTOGROUP/cgroup muck, right?