Re: weird realtek gigabit ethernet issue

[Shaya Potter <spotter@yucs.org>]

Giangiacomo Mariotti wrote:
> On Mon, Dec 8, 2008 at 6:56 AM, Shaya Potter <spotter@yucs.org> 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

perhaps, it also show me no dropped packets, but that would indicate a
bug in /proc/net/dev.

root@nas:~# cat /proc/net/dev ; sleep 1; cat /proc/net/dev
Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes
   packets errs drop fifo colls carrier compressed
    lo:    6544      87    0    0    0     0          0         0
6544      87    0    0    0     0       0          0
  eth0:3088491699 2376860    0 672445284    0     0          0         0
1288945906 1663182    0    0    0     0       0          0
Inter-|   Receive                                                |  Transmit
 face |bytes    packets errs drop fifo frame compressed multicast|bytes
   packets errs drop fifo colls carrier compressed
    lo:    6544      87    0    0    0     0          0         0
6544      87    0    0    0     0       0          0
  eth0:3088491983 2376864    0 802845154    0     0          0         0
1288948788 1663188    0    0    0     0       0          0