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Diffstat (limited to 'doc/guides/nics/virtio.rst')
| -rw-r--r-- | doc/guides/nics/virtio.rst | 40 |
1 files changed, 37 insertions, 3 deletions
diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst index ca09cd20..7c099fb7 100644 --- a/doc/guides/nics/virtio.rst +++ b/doc/guides/nics/virtio.rst @@ -201,7 +201,7 @@ The packet transmission flow is: Virtio PMD Rx/Tx Callbacks -------------------------- -Virtio driver has 3 Rx callbacks and 2 Tx callbacks. +Virtio driver has 4 Rx callbacks and 3 Tx callbacks. Rx callbacks: @@ -215,6 +215,9 @@ Rx callbacks: Vector version without mergeable Rx buffer support, also fixes the available ring indexes and uses vector instructions to optimize performance. +#. ``virtio_recv_mergeable_pkts_inorder``: + In-order version with mergeable Rx buffer support. + Tx callbacks: #. ``virtio_xmit_pkts``: @@ -223,6 +226,8 @@ Tx callbacks: #. ``virtio_xmit_pkts_simple``: Vector version fixes the available ring indexes to optimize performance. +#. ``virtio_xmit_pkts_inorder``: + In-order version. By default, the non-vector callbacks are used: @@ -234,7 +239,7 @@ By default, the non-vector callbacks are used: Vector callbacks will be used when: -* ``txq_flags`` is set to ``VIRTIO_SIMPLE_FLAGS`` (0xF01), which implies: +* ``txmode.offloads`` is set to ``0x0``, which implies: * Single segment is specified. @@ -252,8 +257,14 @@ The corresponding callbacks are: Example of using the vector version of the virtio poll mode driver in ``testpmd``:: - testpmd -l 0-2 -n 4 -- -i --txqflags=0xF01 --rxq=1 --txq=1 --nb-cores=1 + testpmd -l 0-2 -n 4 -- -i --tx-offloads=0x0 --rxq=1 --txq=1 --nb-cores=1 + +In-order callbacks only work on simulated virtio user vdev. + +* For Rx: If mergeable Rx buffers is enabled and in-order is enabled then + ``virtio_xmit_pkts_inorder`` is used. +* For Tx: If in-order is enabled then ``virtio_xmit_pkts_inorder`` is used. Interrupt mode -------------- @@ -318,3 +329,26 @@ Here we use l3fwd-power as an example to show how to get started. $ l3fwd-power -l 0-1 -- -p 1 -P --config="(0,0,1)" \ --no-numa --parse-ptype + + +Virtio PMD arguments +-------------------- + +The user can specify below argument in devargs. + +#. ``vdpa``: + + A virtio device could also be driven by vDPA (vhost data path acceleration) + driver, and works as a HW vhost backend. This argument is used to specify + a virtio device needs to work in vDPA mode. + (Default: 0 (disabled)) + +#. ``mrg_rxbuf``: + + It is used to enable virtio device mergeable Rx buffer feature. + (Default: 1 (enabled)) + +#. ``in_order``: + + It is used to enable virtio device in-order feature. + (Default: 1 (enabled)) |