LPT interruptstorm

Willem Jan Withagen wjw at withagen.nl
Mon Aug 2 04:59:25 PDT 2004


From: "Ian FREISLICH" <if at hetzner.co.za>
> "Willem Jan Withagen" wrote:
> > Hi,
> >
> > Must be a FAQ, but I did not find anything ...
> >
> > When wanting to print thru /dev/lpt0 the kernel now starts to complain about
> > interruptstorms. Something I can imagine, since printing can generate > 1000
> > ints/sec.
> > Problem is that the current document (500k) is now printed at 100
> > interrupts/sec.
> >
> > That's going to take some time....
> > How do I prevent this from happening?
>
> /etc/sysctl.conf: hw.intr_storm_threshold=2000
>
> OR
>
> /boot/device.hints: hint.ppc.0.flags="0x8"
>
> Make sure your bios is set to ecp/epp for the printer port, or the
> second option will fail.  A couple of people around here have also
> suggested 'lptcontrol -e', but every time I've tried that (even
> with lpd stopped) I get 'lptcontrol: open: Device busy'.  I'm not
> sure what keeps the printer port open other than lpd.

Setting the sysctl worked.
But now watching it with sysstat, I see that the interrupts go up as high as
65.000 ????

But instead of > 40 minutes, it now is printed in 3 secs.

Thanx,
--WjW



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