[plug] What's "too much work at interrupt"?

[Bernd Felsche]

On Tuesday 07 September 2004 20:08, James Devenish wrote:
> In message <200409071948.51026 at death.2.spammers>
>
> on Tue, Sep 07, 2004 at 07:48:51PM +0800, Bernd Felsche wrote:
> > On Tuesday 07 September 2004 14:53, James Devenish wrote:
> > > Driver efficiency; hardware tuning?
> >
> > I doubt it.
> > Athlon 2000 with 512MB of RAM.
>
> So, you're saying that we can assume the CPU is so fast that a bad
> driver would be of no consequence? You hadn't previously described the
> usage conditions, e.g. did you have 50 users copying files over a

System *idle* except for the one scp.

> Thinnet network, or 100 users on a switched gigabit link with encrypted
> tunnels? Obviously, the fact remains that *something's* generating those
> "too much work" Ethernet messages, and they are most often associated
> with busy networks => load on the card, and performance issues with the
> drivers or interrupts, busyness on the server, etc. The eepro100 driver,
> for instance, can flake out completely once it starts generating these
> messages. But I have heard that the Intel driver copes better. This
> implies there is something in the design of the software or the use of
> proprietary hardware features that can circumvent the problem (hence =>
> driver efficiency or hardware tuning). To address the "suddenness" of
> these errors, can you confirm that you've ruled out abnormalities in the
> ambient network activity? (That is, could it be that an external
> abnormality is highlighting a latent problem with the software drivers?)

It used to work without the errors. Just a few days ago.

The system is acting as little more than a router to a firewall on
the NIC, with a dialup modem. OK... it's a local email server but
with one user, on the other NIC, that can be ignored, I'd say.
Besides; the problem shows when there is heavy RX traffic on the
8139. Log files show no errors other than when I'm archiving the
firewall's logs.

8139too driver is quite mature. Little need to "tune" it all of the
sudden. It used to hum along at "better than 100%" a week ago.
Now it's unable to sustain anything liek that; less than 200 kbps.

The reason I was asking was to determine if it's the NIC that's
dead; or the DMA/interrupt chip. If only the NIC; I'll plug another
in the PCI bus. If it's DMA/interrupt, then it's a new motherboard.

-- 
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