interrupt storm detected

[Balanga Bar]

Wasn't sure how to check whether the correct PHY indexes were being used
but did notice differences in the boot logs between 11.2 and 12.0


Here's what I got under 11.2:-
Code:

FreeBSD clang version 6.0.0 (tags/RELEASE_600/final 326565) (based on
LLVM 6.0.0)
CPU: Feroceon 88FR131 rev 1 (**unknown 4** core)
  Little-endian DC enabled IC disabled WA disabled DC streaming enabled
  BTB disabled L2 enabled L2 prefetch enabled
  WB enabled LABT branch prediction disabled
  16KB/32B 4-way instruction cache
  16KB/32B 4-way write-back-locking-C data cache
real memory  = 134213632 (127 MB)
avail memory = 121294848 (115 MB)

and with 12.0:-
Code:

FreeBSD clang version 6.0.1 (tags/RELEASE_601/final 335540) (based on
LLVM 6.0.1)
CPU: Feroceon 88FR131 rev 1 (**unknown 4** core)
  Little-endian DC enabled IC enabled WA disabled DC streaming enabled
  BTB disabled L2 enabled L2 prefetch enabled
  WB enabled LABT branch prediction enabled
  16KB/32B 4-way instruction cache
  16KB/32B 4-way write-back-locking-C data cache
real memory  = 0 (0 MB)
avail memory = 120799232 (115 MB)

Could "IC (en/dis)abled" or "LABT branch prediction (en/dis)abled" be
responsible for the interrupt storm?

I've no idea what these terms refer to...



On Wed, Apr 17, 2019 at 6:33 PM Ian Lepore <ian at freebsd.org> wrote:

> On Wed, 2019-04-17 at 19:23 +0100, Balanga Bar wrote:
> > After building FreeBSD 12.0-RELEASE for ARM I managed to boot up my
> > GoFlex
> > Home booting up without getting kernel panics which I did with 11.2,
> > but
> > instead I get a msg every second or so saying:-
> >
> > interrupt storm detected on "intr13:" throttling interrupt source
> >
> > After some experimenting I managed to run vmstat -i which showed:-
> >
> > interrupt                          total       rate
> > irq1: timer0                       27224        201
> > irq12: mge0                         6037         45
> > irq13: mge0                        11003         81
> > irq19: ehci0                        5665         42
> > irq33: uart0                         247          2
> > Total                              50176        371
> >
> >
> > Is there anyting I can do to stop this storm?
> >
> > I tried adding hw.intr_storm_threshold=4000 to /etc/sysctl.conf, but
> > that
> > made no difference.
> >
>
> Check whether the right PHY indexes are being used.  I've seen kirkwood
> systems put the PHYs on 0 & 1, 0 & 4, and 0 & 8.  I've seen interrupt
> storms on mge before.  I'm not positive the PHY numbers and the irq
> storms are related, that's just two random things I remember from the
> past.
>
> -- Ian
>
>