Re: Rx overruns with e1000 card

From: Mark Huth (
Date: Tue Jul 29 2003 - 16:12:40 EST

Rx overruns are generally caused by the inability of the device to get
sufficient bus bandwidth to offload the data. The bandwidth of a 66MHz
32-bit PCI bus is just barely adequate to serve a single full-duplex GE.
 Add a couple of bridges, a little congestion, some contention from
other devices, and you might see this problem, especially if you are
trying to poll the device at the same time, since that causes further
contention/disruption to the data flow on the PCI bus. Since both
devices are on the same PCI bus, the two controllers interfer with each
other, as well.

What percentage of packets are getting the overruns?

Mark Huth

Shilpi Agarwal wrote:

>I am running a Pentium 4 machine 2.53 Ghz machine with 1Ghz RAM. Kernel is 2.4.18.
>I am running it in Polling mode. The problem is i am having some occasional
>packet loss due to receive overruns as shown by e1000 statistics at the packet
>rate above 10000 (64 bytes) ...
>Can any one please help me why i am getting this error?? The pci settings for
>the NIC is ..the machine has anpther onboard NIC.
>01:00.0 Ethernet controller: Intel Corp. 82544GC Gigabit Ethernet Controller (re
>v 02)
> Subsystem: Intel Corp. PRO/1000 T Desktop Adapter
> Flags: bus master, 66Mhz, medium devsel, latency 252, IRQ 11
> Memory at ff8e0000 (32-bit, non-prefetchable) [size=128K]
> Memory at ff8c0000 (32-bit, non-prefetchable) [size=128K]
> I/O ports at dc00 [size=32]
> Expansion ROM at ff8a0000 [disabled] [size=128K]
> Capabilities: [dc] Power Management version 2
> Capabilities: [e4] PCI-X non-bridge device.
> Capabilities: [f0] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable
>01:08.0 Ethernet controller: Intel Corp.: Unknown device 1039 (rev 81)
> Subsystem: Intel Corp.: Unknown device 300e
> Flags: bus master, medium devsel, latency 32, IRQ 11
> Memory at ff89f000 (32-bit, non-prefetchable) [size=4K]
> I/O ports at d880 [size=64]
> Capabilities: [dc] Power Management version 2
>Shilpi Agarwal
>Graduate Student
>Dept of Electrical Engineering
>University of Wisconsin
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