[lkml]   [2020]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting
On Thu, Jul 30, 2020 at 09:23:44AM +0200, Kurt Kanzenbach wrote:
> Hi Vladimir,
> On Wed Jul 29 2020, Vladimir Oltean wrote:
> > For more context, here is my original report of the issue:
> >
> >
> > Just like you, I could not reproduce the RCU stalls and system hang on a
> > 5.6-rt kernel, just on mainline and derivatives, using the plain
> > defconfig.
> >
> > The issue is not specific to Layerscape or i.MX8, but rather I was able
> > to see the same behavior on Marvell Armada 37xx as well as Qualcomm
> > MSM8976.
> >
> > So, while of course I agree that disabling IRQ time accounting for arm64
> > isn't a real solution, it isn't by far an exaggerated proposal either.
> > Nonetheless, the patch is just a RFC and should be treated as such. We
> > are at a loss when it comes to debugging this any further and we would
> > appreciate some pointers.
> Yeah, sure. I'll try to reproduce this issue first. So it triggers with:
> * arm64
> * mainline, not -rt kernel
> * opened serial console
> * irq accounting enabled
> Anything else?
> Thanks,
> Kurt

Thanks for giving a helping hand, Kurt. The defconfig should be enough.
In the interest of full disclosure, the only arm64 device on which we
didn't reproduce this was the 16-core LX2160A. But we did reproduce on
that with maxcpus=1 though. And also on msm8976 with all 8 cores booted.
Just mentioning this in case you're testing on a 16-core system, you
might want to reduce the number a bit.


 \ /
  Last update: 2020-07-30 10:23    [W:0.080 / U:8.896 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site