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Re: coverage

To: andrewm@xxxxxxxxxx (Andrew Morton)
Subject: Re: coverage
From: kuznet@xxxxxxxxxxxxx
Date: Sun, 2 Apr 2000 20:18:27 +0400 (MSK DST)
Cc: netdev@xxxxxxxxxxx
In-reply-to: <38E73398.E1727365@xxxxxxxxxx> from "Andrew Morton" at Apr 2, 0 04:13:15 pm
Sender: owner-netdev@xxxxxxxxxxx
Hello!

> How do you guys test things like:
> 
>   - max_interrupt_work exceeded
...
> My approach to the first two was to put a 5 mSec delay in
> boomerang_rx(), decrease max_interrupt_work to 5 and ping flood it.

It is easy. "ping -f" does not create any real load on the network,
it is pure latency test, when there is always only one packet in flight.
Do not use it. Just write simple program, sending small udp packets
without gaps, or use tools sort of netperf. To create extremal load,
it is possible to use pgen tool by Robert Olsson
(ftp://robur.slu.se:/pub/Linux/tmp/), it is a bit out of date,
but easy to update.


>   - Tx stuck, invoke tx_timeout

I think any man working with network has in his table some broken hub,
which generates only collisions. 8) Mmm... what will occur if to plug
crossed pair to two hub slots? Will it simulate broken hub then?
(I did not advise you to do this! 8))

Seriously, you can just to skip some TX ring refilling deliberately
to trigger this condition.

Alexey

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