TCP differences in 7.2 vs 7.1

[David Samms]

Xin LI wrote:
> Hi David,
> 
> David Samms wrote:
>> After upgrading to 7.2 (amd64) some customers complained of very poor
>> bandwidth.  Upon investigation all the effected customers were ATT DSL
>> clients located all over the USA, not in a single city, nor were other
>> ISPs effected.  The server is a Supermicro with  dual (quad core)
>> processors with a single Intel fxp network card on a 100mbit connection.
> 
> Could you please try if this would help:
> 
> 	sysctl net.inet.tcp.tso=0
> 
> Cheers,
> - --
> Xin LI <delphij at delphij.net>	http://www.delphij.net/
> FreeBSD - The Power to Serve!

Xin LI,

Thank you for your help.

Setting sysctl net.inet.tcp.tso=0 resolved the issue completely.   What 
does sysctl net.inet.tcp.tso=0 do?  Where can I read more about the 
option?  I captured tcpdumps of a single file transfer to 7.1, 7.2 and 
7.2 with sysctl net.inet.tcp.tso=0, but they are to large to attach to 
this list.  Let me know if you are interested in viewing the dump files.

Thanks again for your assistance!