Re: weird realtek gigabit ethernet issue

From: Giangiacomo Mariotti
Date: Mon Dec 08 2008 - 02:34:45 EST


On Mon, Dec 8, 2008 at 6:56 AM, Shaya Potter <spotter@xxxxxxxx> wrote:
> [please cc me in any response as not subscribed]
>
> I have an Asus M3A78-EM motherboard with a "Realtek Semiconductor Co.,
> Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)"
> (per lspci)
>
> which is using the r8169 module on ubuntu intrepid (specifically ubuntu
> kernel 2.6.27-9-generic)
>
> kernel reports
>
> RTL8168c/8111c at 0xf88be000, 00:22:15:a1:d2:41, XID 3c4000c0 IRQ 222
>
> well, what's the issue, its going crazy on the dropped packets, even
> when the only thing connected to it is is an ssh session.
>
> namely ifconfig shows
>
> eth0 Link encap:Ethernet HWaddr 00:22:15:a1:d2:41
> inet addr:192.168.0.41 Bcast:192.168.0.255 Mask:255.255.255.0
> inet6 addr: fe80::222:15ff:fea1:d241/64 Scope:Link
> UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> RX packets:499 errors:0 dropped:2867537736 overruns:0 frame:0
> TX packets:538 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:38995 (38.9 KB) TX bytes:87571 (87.5 KB)
> Interrupt:222 Base address:0xe000
>
> and the dropped count keeps on cycling through its entire space rapidly.
>
> it's running in gigabit mode
>
> root@nas:/home/spotter# mii-tool
> eth0: negotiated 1000baseT-FD flow-control, link ok
>
> I have no idea why. never seen anything like this before. been
> wondering what could be doing it.
>
> in investigating the driver
>
> /*
> * The driver does not support incoming fragmented
> * frames. They are seen as a symptom of over-mtu
> * sized frames.
> */
> if (unlikely(rtl8169_fragmented_frame(status))) {
> dev->stats.rx_dropped++;
> dev->stats.rx_length_errors++;
> rtl8169_mark_to_asic(desc, tp->rx_buf_sz);
> continue;
> }
>
> so it would appear to be some issue relating to fragmented frames.
>
> However, based on the amount of packets received, it seems to be very
> strange.
>
> I would have thought maybe it had something to do with jumbo packets,
> but all the machines on the net are using an mtu of 1500 currently.
>
> anyways, any explanation, if its not a bug, would be appreciated.
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Did you try using iproute2 instead of ifconfig? I have the same
problem with ifconfig, but iproute says that there's no problem:
ifconfig :

eth0 Link encap:Ethernet HWaddr 00:1f:d0:ae:41:0e
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:16100 errors:0 dropped:152365729778 overruns:0 frame:0
TX packets:15465 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:15693968 (14.9 MiB) TX bytes:2565833 (2.4 MiB)
Interrupt:245 Base address:0xc000

ip -stats link show eth0 :

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast
state UNKNOWN qlen 1000
link/ether 00:1f:d0:ae:41:0e brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
15677088 16028 0 0 0 0
TX: bytes packets errors dropped carrier collsns
2536480 15384 0 0 0 0



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