lots of bad checksum on igb

k simon chio1990 at gmail.com
Thu May 22 09:36:27 PDT 2014

   I noticed that Pyun have fixed some bugs about TSO&.CHECKSUM offload 
issues on FreeBSD recently. Does the same issues happend on Dfly ?


于 14-4-18 10:12, k simon 写道:
>    And I found lo0 reported bad checksum too.
> 于 14-4-18 9:38, k simon 写道:
>> Hi,Matthew,
>>    When it report bad checksum, the web pages can not opened. If
>> disabled the HW checksum, then it acts normally. I think it's a real
>> problem and I would take a bce card try again.
>> Simon
>> 于 14-4-18 2:02, Matthew Dillon 写道:
>>> Bad checksums reported by tcpdump are not necessarily actually bad. What
>>> is happening is that the checksum field is not updated when HW checksums
>>> are enabled... the code depends on the HW to tell it if the checksum is
>>> bad or not (on receive), and depends on the HW to generate the checksum
>>> (on transmit).  So the packet in the mbuf which tcpdump is parsing may
>>> not have a filled-in checksum field.
>>> If you are getting actual communications glitches, e.g. pings not
>>> returning, tcp throughput problems, and so forth, then you might have a
>>> real problem.
>>> -Matt

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