Re: [dpdk-dev] [PATCH v5 0/2] bond: mode 4 support

["Wodkowski, PawelX" <pawelx.wodkowski@intel.com>]

Some information detail about mode mode 4 of link bonding:

This mode is described in IEEE 802.3ad/AX standard described. It is also
described here
https://www.kernel.org/doc/Documentation/networking/bonding.txt.

In this implementation we have an array of mode 4 setting for each slave.
There is also assumption that for every port is one aggregator (it might
be unused if better is found).

Difference in this implementation vs ex Linux implementation:
- this implementation it is not directly based on state machines but current
  state is calculated from actor and partner states (and other things too).

Some implementation details:
- during rx burst every packet Is checked if this is LACP or marker packet.
  If it is LACP frame it is passed to mode 4 logic using slaves rx ring  and 
  removed from rx buffer before it is returned
- in tx burst, packets from mode 4 (if any) are injected into each slave.
- there is a timer running in background to process/produce mode 4 
  frames form rx/to tx functions.

Some requirements for this mode:
- for LACP mode to work rx and tx burst functions must be invoked
  at least in 100ms intervals (testpmd modified to satisfy this requirement)
- provided buffer to rx burst should be at least 2x slave count size. This is
  not needed but might increase performance especially during initial
  handshake.

Please inform me if you need additional information on this.

Pawel