Lennert,
It sounds like you are running into a bug we had with NAPI in that
e1000 driver. Robert actually found it. :-) Please try the 5.7.6
driver available from Sourceforge. It has the fixed NAPI code in it.
Let us know if this fixes the problem.
Thanks,
John
On Tue, 1 Mar 2005 14:59:31 +0100, Lennert Buytenhek
<buytenh@xxxxxxxxxxxxxx> wrote:
> Hi all,
>
> I'm seeing some strange issues with an e1000 NIC. I'm flooding it
> with tinygrams from a packet generator and then abruptly stop the
> generator. The last few packets from the burst don't come through
> until after two seconds. Sometimes there are multiple trailing
> bursts, each of them separated by two seconds.
>
> For example: (The low 24 bits of the destination address are set
> to the packet sequence number by the generator.)
>
> 14:44:19.649874 IP 10.10.0.0 > 1.4.10.11: [|tcp]
> 14:44:19.649878 IP 10.10.0.0 > 1.4.10.12: [|tcp]
> 14:44:19.649882 IP 10.10.0.0 > 1.4.10.13: [|tcp]
> 14:44:19.649887 IP 10.10.0.0 > 1.4.10.14: [|tcp]
> 14:44:19.649891 IP 10.10.0.0 > 1.4.10.15: [|tcp]
> 14:44:19.649895 IP 10.10.0.0 > 1.4.10.16: [|tcp]
> 14:44:19.649899 IP 10.10.0.0 > 1.4.10.17: [|tcp]
> 14:44:21.650293 IP 10.10.0.0 > 1.4.10.18: [|tcp] <=== delayed
> 14:44:21.650303 IP 10.10.0.0 > 1.4.10.19: [|tcp]
> 14:44:21.650308 IP 10.10.0.0 > 1.4.10.20: [|tcp]
> 14:44:21.650312 IP 10.10.0.0 > 1.4.10.21: [|tcp]
> 14:44:21.650316 IP 10.10.0.0 > 1.4.10.22: [|tcp]
> 14:44:21.650320 IP 10.10.0.0 > 1.4.10.23: [|tcp]
> 14:44:21.650324 IP 10.10.0.0 > 1.4.10.24: [|tcp]
> 14:44:21.650328 IP 10.10.0.0 > 1.4.10.25: [|tcp]
> 14:44:21.650332 IP 10.10.0.0 > 1.4.10.26: [|tcp]
>
> I wrote the packet generator code myself (ixp2400 platform), but I've
> verified that the packets do leave the generator back-to-back. What's
> also strange is that when these trailing bursts come in, the interface
> statistics counters do not change -- the packets in the trailing bursts
> have already been counted by the time they show up in tcpdump.
>
> Jamal suspects a NAPI 'rotting packet' issue, which doesn't sound all
> that unlikely. (Oh, this is kernel 2.6.10-something with e1000 driver
> version "5.5.4-k2-NAPI".)
>
> Ideas?
>
> cheers,
> Lennert
>
>
--
Cheers,
John
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