[dpdk-dev] [PATCH RFC 11/11] ixgbe/mbuf: add TSO support

Thomas Monjalon thomas.monjalon at 6wind.com
Mon May 19 14:32:59 CEST 2014


Hi,

I'll try so sum it up this interesting discussion about checksum API for TSO.

We know at least 2 checksum methods:
- the standard one
- the special one for ixgbe TSO
In Linux ixgbe, checksum is redone in the driver for TSO case.

We want to compute checksum in the application/stack in order to prevent 
driver from modifying packet data, that could cause cache miss.
But the application cannot always know which checksum method to use because it 
doesn't have to know which driver will process the packet.
So we have to choose which checksum method can be done in the application 
without driver processing. It's not an easy choice.

It seems simpler and reasonnable to choose the standard pseudo-header checksum 
method as it is done in Linux.
Having a stable and generic API is something important we must target.

Thanks
-- 
Thomas


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