bizarre em + TSO + MSS issue in RELENG_7

Jack Vogel jfvogel at
Sun Nov 18 16:04:26 PST 2007

On Nov 17, 2007 9:44 PM, Pyun YongHyeon <pyunyh at> wrote:
> It seems that em(4) uses EM_TSO_SIZE(64K) to create DMA tag. A packet
> can have 64K payload under TSO so its the mximum size of the mbuf
> chain would be 64K + sizeof(link layer). So I guess the EM_TSO_SIZE
> should be increased to hold sizeof(link layer).
> It had been a long time since I looked into em(4) so I'm not sure.

Hmm, you are right about this Pyun, I think this should be fixed, although
I do not see how that would effect this since Mike's payloads are always
way under this. Still I'll keep this in mind to be changed. Thanks for pointing
it out.


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