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Re: Chained vs. shared EtherNEC interrupts - was: Re: [SOLVED] Re: ARAnyM VMs with Debian hanging at 100% CPU usage

Hi Michael,

On Mon, Jul 30, 2012 at 1:09 AM, Michael Schmitz <schmitzmic@gmail.com> wrote:
> Looks like it sort of works - but now I'm stuck at the very same point
> that got me
> to playing tricks with shared interrupts in the first place: the
> interrupt watchdog
> kicks in and disables the eip_interrupt handler.


> The good news: sharing the timer interrupt with other devices (USB
> function on NetUSBee) is trival.
> And the EtherNEC still functions even after its interrupts have been
> disabled - how that works is a
> bit of a mystery to me, but who am I to argue with serendipity?
> Latency mushrooms to 50ms, and
> data rate drops from 70k/sec to 20k/sec but it's still alive.

My initial guess was that the transmit code also checks for received
packets somewhere, but I can't seem to find this in the code. Oh well...

> Geert - can we do anything other than using noirqdebug = 1 to ensure
> this doesn't impact on network
> performance?

Hmm, so we do need IRQF_SHARED inside an #ifdef.
If we can't convince Paul, that'll mean another 8390 driver. Sigh...



Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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