Errors using span interface on if_bridge(4)

[hiren panchasara]

On Sun, Feb 2, 2014 at 7:32 PM, hiren panchasara
<hiren.panchasara at gmail.com> wrote:
> On Sun, Feb 2, 2014 at 11:19 AM, hiren panchasara
> <hiren.panchasara at gmail.com> wrote:
>> On Sat, Feb 1, 2014 at 5:16 PM, hiren panchasara
>> <hiren.panchasara at gmail.com> wrote:
>>
>>>
>>> -bash-4.2$ sysctl -a | grep mac_stats.checksum_errs
>>> dev.ix.0.mac_stats.checksum_errs: 0
>>> dev.ix.1.mac_stats.checksum_errs: 0
>>> dev.ix.2.mac_stats.checksum_errs: 0
>>> dev.ix.3.mac_stats.checksum_errs: 3371119  <-- most of them fail checksum
>>
>> In ixgbe.c :
>> ixgbe_add_hw_stats() has
>>          SYSCTL_ADD_UQUAD(ctx, stat_list, OID_AUTO, "checksum_errs",
>>                          CTLFLAG_RD, &stats->xec,
>>                          "Checksum Errors");
>>
>> which is updated in ixgbe_update_stats_counters()
>> adapter->stats.xec += IXGBE_READ_REG(hw, IXGBE_XEC);
>>
>> ixgbe_type.h defines
>> #define IXGBE_XEC               0x04120
>>
>> So, this is something that firmware of the card updates? We just read
>> that register from drivers.
>
> ix3 at pci0:66:0:1:        class=0x020000 card=0x7a118086 chip=0x10fb8086
> rev=0x01 hdr=0x00
>     vendor     = 'Intel Corporation'
>     device     = '82599EB 10-Gigabit SFI/SFP+ Network Connection'
>     class      = network
>     subclass   = ethernet
>
> I found following in 82599 controller spec update:
> http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/82599-10-gbe-controller-spec-update.pdf#G2.1474004
> http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/82599-10-gbe-controller-spec-update.pdf#G2.2301787
>
> Thought here I am sending unicast tcp traffic with iperf3.

I tried to use netperf to generate smaller size packets (64 bytes) and
with that I saw only 0.004% packets reporting checksum errors.

$ netperf -H 10.73.149.91 -t TCP_STREAM -- -m 64 -D
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.73.149.91
() port 0 AF_INET : nodelay : histogram : interval : dirty data : demo
Recv       Send     Send
Socket   Socket  Message  Elapsed
Size       Size       Size        Time       Throughput
bytes     bytes      bytes       secs.      10^6bits/sec

 65536  65536     64          10.00       56.92

Anything larger was showing 93% packets with checksum error. (as I've
been reporting in this thread).

cheers,
Hiren