Re: [2.2.9] performance problem on 100MBit network

Rogier Wolff (R.E.Wolff@BitWizard.nl)
Thu, 27 May 1999 15:11:08 +0200 (MEST)

David S. Miller wrote:
> Date: Sat, 22 May 1999 16:08:30 +0200
> From: Jochen Heuer <jogi@planetzork.ping.de>
>
> Sometimes I get ping times of up to 20 seconds(!) while normaly
> ping times are ~0.3ms. If this happens I have to reboot either my
> server or my client.
>
> What can I do to debug this if it happens again?
>
> Let me guess, you see this behavior on systems where DHCP is running
> in some way? And it happens about when a client rebinds, and the
> machine in question is going ARP crazy if you watch it on the network
> with tcpdump?

Another possibility is that he has an RTL8139 card in the machine.
There is an obscure bug in that driver that causes the card to get
a certain "backlog". One packet is transmitted for every packet
received.

If that's the case, Jochen will see that if he starts a parallel ping
to the same machine on a different xterm, the ping-times will drop to
10s.

I haven't had time to debug this yet. (and stupid me, the machine has
gone into production :-( )

> Did I guess right?

Did I guess right?

Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
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