[dpdk-dev] [PATCH v7 0/3]: Add LRO support to ixgbe PMD

[Vlad Zolotarov <vladz@cloudius-systems.com>]

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 v7:
   - Free not-yet-completed RSC aggregations in rte_eth_dev_stop() flow.
   - Fixed rx_bulk_alloc_allowed and rx_vec_allowed initialization:
      - Don't set them to FALSE in rte_eth_dev_stop() flow - the following
        rte_eth_dev_start() will need them.
      - Reset them to TRUE in rte_eth_dev_configure() and not in a probe() flow.
        This will ensure the proper behaviour if port is re-configured.
   - Reset the sw_ring[].mbuf entry in a bulk allocation case.
     This is needed for ixgbe_rx_queue_release_mbufs().
   - _recv_pkts_lro(): added the missing memory barrier before RDT update in a
     non-bulk allocation case.
   - Don't allow RSC when device is configured in an SR-IOV mode.

New in v6:
   - Fix of the typo in the "bug fixes" series that broke the compilation caused a
     minor change in this follow-up series.  

New in v5:
   - Split the series into "bug fixes" and "all the rest" so that the former could be
     integrated into a 2.0 release.
   - Put the RTE_ETHDEV_HAS_LRO_SUPPORT definition at the beginning of rte_ethdev.h.
   - Removed the "TODO: Remove me" comment near RTE_ETHDEV_HAS_LRO_SUPPORT.

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 (3):
  ixgbe: Cleanups
  ixgbe: Code refactoring
  ixgbe: Add LRO support

 lib/librte_ether/rte_ethdev.h       |   9 +-
 lib/librte_pmd_ixgbe/ixgbe_ethdev.c |  29 +-
 lib/librte_pmd_ixgbe/ixgbe_ethdev.h |   5 +
 lib/librte_pmd_ixgbe/ixgbe_rxtx.c   | 738 ++++++++++++++++++++++++++++++++----
 lib/librte_pmd_ixgbe/ixgbe_rxtx.h   |   6 +
 5 files changed, 710 insertions(+), 77 deletions(-)

-- 
2.1.0