[ofa-general] Re: [PATCH v4 for-2.6.27] IPOIB: add LRO support.

[Eli Cohen]

On Wed, Jul 02, 2008 at 04:24:25PM +0300, Or Gerlitz wrote:
> OK, I understand that to some extent its fine to do what others (BTW its 
> only 4 drivers under drivers/net that use LRO, so the sample size is kind 
> of small) do. I still don't see why 64 makes sense, for example ipoib 
> supports LSO on the xmit side, which means the network stack would submit 
> SKBs whose data size is up to 64K, assuming the common mtu is 2K-epsilon I 
> would use a value of 64K/2K = ~32 for the max_aggr value, why use 64 ?!
>
I don't see a connection to using or not using LSO -- the 64K comes
from the fact that an IP datagram's max length is 64K. And since LRO
involves generating at the receiver a hand made IP datagram, the max
length is 64K. There is a connection to TCP MSS which could be up to
MTU but could be smaller too. I don't see a problem keeping the
current value.