TSO and FreeBSD vs Linux

[Julian Elischer]

On 8/14/13 3:23 PM, Lawrence Stewart wrote:
> On 08/14/13 16:33, Julian Elischer wrote:
>
>>> They switched to using an initial window of 10 segments some time ago.
>>> FreeBSD starts with 3 or more recently, 10 if you're running recent
>>> 9-STABLE or 10-CURRENT.
>> I tried setting initial values as shown:
>>    net.inet.tcp.local_slowstart_flightsize: 10
>>    net.inet.tcp.slowstart_flightsize: 10
>> it didn't seem to make too much difference but I will redo the test.
> Assuming this is still FreeBSD 8.0 as you mentioned out-of-band,
> changing those variables without disabling rfc3390 will have no effect.
>
> I think (check the driver code in question as I'm not sure) that if you
> "ifconfig <if> lro" and the driver has hardware support or has been made
> aware of our software implementation, it should DTRT.

so I ran on 9.2-beta ( a week or two old) and it had similar problems..
only worse.. 9.2 actually sends multiple packets when is doesn't need to..
     http://people.freebsd.org/~julian/fbsd9.png

>
> Cheers,
> Lawrence
>
>