[PATCH v4 0/5]: Add LRO support to ixgbe PMD

[Vlad Zolotarov <vladz-RmZWMc9puTNJc61us3aD9laTQe2KTcn/@public.gmane.org>]

This series adds the missing flow for enabling the LRO in the ethdev and
adds a support for this feature in the ixgbe PMD. There is a big hope that this
initiative is going to be picked up by some Intel developer that would add the LRO support
to other Intel PMDs. ;)
 
The series starts with some cleanup work in the code the final patch (the actual adding of
the LRO support) is going to touch/use/change. There are still quite a few issues in the ixgbe
PMD code left but they have to be a matter of a different series and I've left a few "TODO"
remarks in the code.
 
The LRO ("RSC" in Intel's context) PMD completion handling code follows the same design as the
corresponding Linux and FreeBSD implementation: pass the aggregation's cluster HEAD buffer to
the NEXTP entry of the software ring till EOP is met.
 
HW configuration follows the corresponding specs: this feature is supported only by x540 and
82599 PF devices.
 
The feature has been tested with seastar TCP stack with the following configuration on Tx side:
   - MTU: 400B
   - 100 concurrent TCP connections.
 
The results were:
   - Without LRO: total throughput: 0.12Gbps, coefficient of variance: 1.41%
   - With LRO:    total throughput: 8.21Gbps, coefficient of variance: 0.59%
 
This is an almost factor 80 improvement.

New in v4:
   - Remove CONFIG_RTE_ETHDEV_LRO_SUPPORT from config/common_linuxapp.
   - Define RTE_ETHDEV_HAS_LRO_SUPPORT in rte_ethdev.h.
   - As a result of "ixgbe: check rxd number to avoid mbuf leak" (352078e8e) Vector Rx
     had to get the same treatment as Rx Bulk Alloc (see PATCH4 for more details).
     
New in v3:
   - ixgbe_rx_alloc_bufs(): Always reset refcnt of the buffers to 1. Otherwise rte_pktmbuf_free()
     won't free them.

New in v2:
   - Removed rte_eth_dev_data.lro_bulk_alloc and added ixgbe_hw.rx_bulk_alloc_allowed
     instead.
   - Unified the rx_pkt_bulk callback setting (a separate new patch).
   - Fixed a few styling and spelling issues.

Vlad Zolotarov (5):
  ixgbe: Cleanups
  ixgbe: Bug fix: Properly configure Rx CRC stripping for x540 devices
  ixgbe: Code refactoring
  ixgbe: Unify the rx_pkt_bulk callback initialization
  ixgbe: Add LRO support

 lib/librte_ether/rte_ethdev.h           |   9 +-
 lib/librte_pmd_ixgbe/ixgbe/ixgbe_type.h |   2 +
 lib/librte_pmd_ixgbe/ixgbe_ethdev.c     |  19 +-
 lib/librte_pmd_ixgbe/ixgbe_ethdev.h     |   5 +
 lib/librte_pmd_ixgbe/ixgbe_rxtx.c       | 886 +++++++++++++++++++++++++++-----
 lib/librte_pmd_ixgbe/ixgbe_rxtx.h       |  28 +-
 6 files changed, 815 insertions(+), 134 deletions(-)

-- 
2.1.0