[dpdk-dev] [PATCH v2 00/17] ixgbe/mbuf: add TSO support

[Olivier Matz <olivier.matz@6wind.com>]

This series add TSO support in ixgbe DPDK driver. This is the second
version of the series. The first version (RFC) was posted 10 days ago
and discussed on the list [1]. The list of changes is provided at the
end of this cover letter.

Also, as discussed previously on the list [2], one problem is that there
is not enough room in rte_mbuf today to store the required information
to implement this feature:
  - a new ol_flag
  - the MSS
  - the L4 header len

A solution would be to increase the size of the mbuf to 2 cache lines
but it could have a bad impact on performance. This series proposes some
rework to drastically reduce the size of the rte_mbuf structures before
implementing the TSO, avoiding to change the mbuf size to 128 bytes.

After the rework of mbuf structures, the size of rte_mbuf structure is
reduced by 9 bytes. The implementation of TSO requires to double the
size of ol_flags (16 to 32 bits) and to double the size of offload
information in order to add the mss and the l4 header length (32 to 64
bits). At the end of the whole series, sizeof(rte_mbuf) is still 64
bytes and 4 bytes are available for future use.

This rework causes a lot of modifications in the mbuf structure,
implying some changes in the applications that directly use the mbuf
structure fields instead of using the API functions (sometimes there is
no function). In my opinion, it's the proper moment for this evolution
as the 1.7.0 window is open.

About TSO, the new fields in mbuf try to be generic enough to apply to
other hardware in the future. To delegate the TCP segmentation to the
hardware, the user has to:

  - set the PKT_TX_TCP_SEG flag in mbuf->ol_flags (this flag implies
    PKT_TX_IP_CKSUM and PKT_TX_TCP_CKSUM)
  - fill the mbuf->hw_offload information: l2_len, l3_len, l4_len, mss
  - calculate the pseudo header checksum and set it in the TCP header,
    as required when doing hardware TCP checksum offload
  - set the IP checksum to 0

Compilation of DPDK and examples is tested for the following
targets: x86_64-*-linuxapp-gcc, i686-*-linuxapp-gcc, x86_64-*-bsdapp-gcc

The mbuf rework series is validated with autotests:

  cd dpdk.org/
  make install T=x86_64-default-linuxapp-gcc
  cd x86_64-default-linuxapp-gcc/
  modprobe uio
  insmod kmod/igb_uio.ko
  python ../tools/igb_uio_bind.py -b igb_uio 0000:02:00.0
  echo 0 > /proc/sys/kernel/randomize_va_space
  echo 1000 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
  echo 1000 > /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages
  mount -t hugetlbfs none /mnt/huge
  make test

TSO is validated with IPv4 and IPv6 with testpmd (see the commit log of
patch "ixgbe: support TCP segmentation offload" for details).

The performance non-regression has been tested with 6WINDGate fast path,
and with test-pmd [3].

[1] http://dpdk.org/ml/archives/dev/2014-May/002322.html
[2] http://dpdk.org/ml/archives/dev/2013-October/thread.html#572
[3] http://dpdk.org/ml/archives/dev/2014-May/002516.html


Changes included in v2:
- rebase on head, resolve conflicts in 3 test-pmd engines
- add more comments in rte_mbuf.h about how to use TSO
- ixgbe: advertise the TSO feature
- ixgbe: small optimization, move some tso code in the if (tx_ol_req)
- split "mbuf: replace data pointer by an offset" (cosmetics vs functional)
- split "ixgbe/mbuf: add TSO support" (ixgbe vs generic changes)
- modifications of external PMDs (memnic, virtio, vmxnet3)
- I did not add the new checksum flags PKT_RX_L4_CKSUM_GOOD and
  PKT_RX_IP_CKSUM_GOOD as proposed on the list. The patch is ready but
  I don't think it should be included in this series.

Olivier Matz (17):
 dpdk             igb/ixgbe: fix IP checksum calculation
 dpdk             mbuf: rename RTE_MBUF_SCATTER_GATHER into
 dpdk             mbuf: remove rte_ctrlmbuf
 dpdk             mbuf: remove the rte_pktmbuf structure
 dpdk             mbuf: merge physaddr and buf_len in a bitfield
 dpdk             mbuf: cosmetic changes in rte_mbuf structure
 dpdk             mbuf: replace data pointer by an offset
 dpdk             mbuf: add functions to get the name of an ol_flag
 dpdk             mbuf: change ol_flags to 32 bits
 dpdk             mbuf: rename vlan_macip_len in hw_offload and increase
 dpdk             testpmd: modify source address to validate checksum
 dpdk             mbuf: generic support of TCP segmentation offload
 dpdk             ixgbe: support TCP segmentation offload
 virtio-net-pmd   pmd: adapt to new rte_mbuf structure
 vmxnet3-usermap  pmd: remove support of old dpdk versions
 vmxnet3-usermap  pmd: adapt to new rte_mbuf structure
 memnic           pmd: adapt to new rte_mbuf structure

Diffstat:
 dpdk.org/app/test-pmd/cmdline.c                                        |   60 -
 dpdk.org/app/test-pmd/config.c                                         |   18
 dpdk.org/app/test-pmd/csumonly.c                                       |   56
 dpdk.org/app/test-pmd/flowgen.c                                        |   26
 dpdk.org/app/test-pmd/icmpecho.c                                       |    6
 dpdk.org/app/test-pmd/ieee1588fwd.c                                    |    6
 dpdk.org/app/test-pmd/macfwd-retry.c                                   |    4
 dpdk.org/app/test-pmd/macfwd.c                                         |   16
 dpdk.org/app/test-pmd/macswap.c                                        |   16
 dpdk.org/app/test-pmd/rxonly.c                                         |   53
 dpdk.org/app/test-pmd/testpmd.c                                        |   14
 dpdk.org/app/test-pmd/testpmd.h                                        |   15
 dpdk.org/app/test-pmd/txonly.c                                         |   59 -
 dpdk.org/app/test/commands.c                                           |    2
 dpdk.org/app/test/test_mbuf.c                                          |  106 -
 dpdk.org/app/test/test_sched.c                                         |    4
 dpdk.org/config/defconfig_i686-default-linuxapp-gcc                    |    2
 dpdk.org/config/defconfig_i686-default-linuxapp-icc                    |    2
 dpdk.org/config/defconfig_x86_64-default-bsdapp-gcc                    |    2
 dpdk.org/config/defconfig_x86_64-default-linuxapp-gcc                  |    2
 dpdk.org/config/defconfig_x86_64-default-linuxapp-icc                  |    2
 dpdk.org/doc/doxy-api.conf                                             |    2
 dpdk.org/examples/dpdk_qat/crypto.c                                    |   22
 dpdk.org/examples/dpdk_qat/main.c                                      |    2
 dpdk.org/examples/exception_path/main.c                                |   13
 dpdk.org/examples/ip_reassembly/ipv4_rsmbl.h                           |   30
 dpdk.org/examples/ip_reassembly/main.c                                 |   10
 dpdk.org/examples/ipv4_frag/Makefile                                   |    4
 dpdk.org/examples/ipv4_frag/main.c                                     |    4
 dpdk.org/examples/ipv4_frag/rte_ipv4_frag.h                            |   42
 dpdk.org/examples/ipv4_multicast/Makefile                              |    4
 dpdk.org/examples/ipv4_multicast/main.c                                |   16
 dpdk.org/examples/l3fwd-power/main.c                                   |    2
 dpdk.org/examples/l3fwd-vf/main.c                                      |    2
 dpdk.org/examples/l3fwd/main.c                                         |   10
 dpdk.org/examples/load_balancer/runtime.c                              |    2
 dpdk.org/examples/multi_process/client_server_mp/mp_client/client.c    |    2
 dpdk.org/examples/quota_watermark/qw/main.c                            |    4
 dpdk.org/examples/vhost/main.c                                         |   43
 dpdk.org/examples/vhost_xen/main.c                                     |   24
 dpdk.org/lib/librte_eal/bsdapp/eal/include/exec-env/rte_kni_common.h   |    2
 dpdk.org/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h |    2
 dpdk.org/lib/librte_mbuf/rte_mbuf.c                                    |  105 -
 dpdk.org/lib/librte_mbuf/rte_mbuf.h                                    |  580 ++++------
 dpdk.org/lib/librte_pmd_e1000/em_rxtx.c                                |  163 +-
 dpdk.org/lib/librte_pmd_e1000/igb_rxtx.c                               |  212 +--
 dpdk.org/lib/librte_pmd_ixgbe/ixgbe_ethdev.c                           |    3
 dpdk.org/lib/librte_pmd_ixgbe/ixgbe_rxtx.c                             |  419 ++++---
 dpdk.org/lib/librte_pmd_ixgbe/ixgbe_rxtx.h                             |   10
 dpdk.org/lib/librte_pmd_pcap/rte_eth_pcap.c                            |   14
 dpdk.org/lib/librte_pmd_virtio/virtio_rxtx.c                           |   20
 dpdk.org/lib/librte_pmd_virtio/virtqueue.h                             |   11
 dpdk.org/lib/librte_pmd_vmxnet3/vmxnet3_rxtx.c                         |   37
 dpdk.org/lib/librte_pmd_xenvirt/rte_eth_xenvirt.c                      |   14
 dpdk.org/lib/librte_pmd_xenvirt/virtqueue.h                            |    4
 dpdk.org/lib/librte_sched/rte_sched.c                                  |   14
 dpdk.org/lib/librte_sched/rte_sched.h                                  |   10
 memnic/pmd/pmd_memnic.c                                                |   14
 vmxnet3-usermap/pmd/vmxnet3.c                                          |  119 --
 virtio-net-pmd/virtio_user.c                                           |   44
 60 files changed, 1217 insertions(+), 1289 deletions(-)


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1.9.2