On Tue, 24 Nov 2015 11:09:56 +0100 Peter Zijlstra <pet...@infradead.org> wrote:
> On Tue, Nov 24, 2015 at 09:12:40AM +0000, Javi Merino wrote: > > On Mon, Nov 23, 2015 at 07:07:06PM +0100, Peter Zijlstra wrote: > > > 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? > > > > The bug only happens when you apply this series and you set the > > system to idle inject 50% of the time. SCHED_AUTOGROUP is already > > part of the kernel and behaves properly with the kernel as is. I > > think that this patch should not introduce new bugs. > > Ah, then I misunderstood your email, agreed. First of all, thanks for testing. Just trying to reproduce this. So let me understand your set up. - 8 cores in total? - you first set 50% idle - then launch 6 busy loops How often you see this happen? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/