improved TSO interface needed

[Andre Oppermann]

Kip Macy wrote:
>> LSO is MicroSlop's term for TSO :) As usual, they rename it, and
>> next they do something non-standard to er 'differentiate' as the
>> euphemism goes...
>>
>> Kinda what Sun's lawsuit back in the 90s against their Java
>> strategy was all about :)
>>
>> Nevertheless, I don't understand Kip either, when we do TSO there
>> is no evidence on the wire, it still has MTU sized packets.  I fail to
>> see why I should care about some LSO spec, what does it break?
> 
> The stack will send down chains where pkthdr.len > 65536 bytes - I'm
> also seeing it send down mbuf chains of 66 mbufs or more. I don't
> think all cards can handle an arbitrary number of descriptors being
> used for a single packet.

Getting an mbuf chain with pkthdr.len > 65536 is a bug.  Can you describe
the test setup a bit more, eg. which programs do you use to generate the
traffic?  And can you instrument the driver to print the exact size of
the oversized chains?  I'm interested if it is just a few bytes more or
generally overshoots by a larger margin.

-- 
Andre