=====================
The MLX5 poll mode driver library (**librte_pmd_mlx5**) provides support for
-**Mellanox ConnectX-4 EN** and **Mellanox ConnectX-4 Lx EN** families of
+**Mellanox ConnectX-4** and **Mellanox ConnectX-4 Lx** families of
10/25/40/50/100 Gb/s adapters as well as their virtual functions (VF) in
SR-IOV context.
be enabled manually by setting ``CONFIG_RTE_LIBRTE_MLX5_PMD=y`` and
recompiling DPDK.
-.. warning::
-
- ``CONFIG_RTE_BUILD_COMBINE_LIBS`` with ``CONFIG_RTE_BUILD_SHARED_LIB``
- is not supported and thus the compilation will fail with this configuration.
-
Implementation details
----------------------
Enabling librte_pmd_mlx5 causes DPDK applications to be linked against
libibverbs.
+Features
+--------
+
+- Multiple TX and RX queues.
+- Support for scattered TX and RX frames.
+- IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of queues.
+- Several RSS hash keys, one for each flow type.
+- Configurable RETA table.
+- Support for multiple MAC addresses.
+- VLAN filtering.
+- RX VLAN stripping.
+- TX VLAN insertion.
+- RX CRC stripping configuration.
+- Promiscuous mode.
+- Multicast promiscuous mode.
+- Hardware checksum offloads.
+- Flow director (RTE_FDIR_MODE_PERFECT, RTE_FDIR_MODE_PERFECT_MAC_VLAN and
+ RTE_ETH_FDIR_REJECT).
+- Secondary process TX is supported.
+- KVM and VMware ESX SR-IOV modes are supported.
+- RSS hash result is supported.
+
+Limitations
+-----------
+
+- Inner RSS for VXLAN frames is not supported yet.
+- Port statistics through software counters only.
+- Hardware checksum offloads for VXLAN inner header are not supported yet.
+- Secondary process RX is not supported.
+
Configuration
-------------
adds additional run-time checks and debugging messages at the cost of
lower performance.
-- ``CONFIG_RTE_LIBRTE_MLX5_SGE_WR_N`` (default **4**)
-
- Number of scatter/gather elements (SGEs) per work request (WR). Lowering
- this number improves performance but also limits the ability to receive
- scattered packets (packets that do not fit a single mbuf). The default
- value is a safe tradeoff.
-
-- ``CONFIG_RTE_LIBRTE_MLX5_MAX_INLINE`` (default **0**)
-
- Amount of data to be inlined during TX operations. Improves latency but
- lowers throughput.
-
- ``CONFIG_RTE_LIBRTE_MLX5_TX_MP_CACHE`` (default **8**)
Maximum number of cached memory pools (MPs) per TX queue. Each MP from
This value is always 1 for RX queues since they use a single MP.
+Environment variables
+~~~~~~~~~~~~~~~~~~~~~
+
+- ``MLX5_PMD_ENABLE_PADDING``
+
+ Enables HW packet padding in PCI bus transactions.
+
+ When packet size is cache aligned and CRC stripping is enabled, 4 fewer
+ bytes are written to the PCI bus. Enabling padding makes such packets
+ aligned again.
+
+ In cases where PCI bandwidth is the bottleneck, padding can improve
+ performance by 10%.
+
+ This is disabled by default since this can also decrease performance for
+ unaligned packet sizes.
+
Run-time configuration
~~~~~~~~~~~~~~~~~~~~~~
- **ethtool** operations on related kernel interfaces also affect the PMD.
+- ``rxq_cqe_comp_en`` parameter [int]
+
+ A nonzero value enables the compression of CQE on RX side. This feature
+ allows to save PCI bandwidth and improve performance at the cost of a
+ slightly higher CPU usage. Enabled by default.
+
+ Supported on:
+
+ - x86_64 with ConnectX4 and ConnectX4 LX
+ - Power8 with ConnectX4 LX
+
+- ``txq_inline`` parameter [int]
+
+ Amount of data to be inlined during TX operations. Improves latency.
+ Can improve PPS performance when PCI back pressure is detected and may be
+ useful for scenarios involving heavy traffic on many queues.
+
+ It is not enabled by default (set to 0) since the additional software
+ logic necessary to handle this mode can lower performance when back
+ pressure is not expected.
+
+- ``txqs_min_inline`` parameter [int]
+
+ Enable inline send only when the number of TX queues is greater or equal
+ to this value.
+
+ This option should be used in combination with ``txq_inline`` above.
+
+- ``txq_mpw_en`` parameter [int]
+
+ A nonzero value enables multi-packet send. This feature allows the TX
+ burst function to pack up to five packets in two descriptors in order to
+ save PCI bandwidth and improve performance at the cost of a slightly
+ higher CPU usage.
+
+ It is currently only supported on the ConnectX-4 Lx family of adapters.
+ Enabled by default.
+
Prerequisites
-------------
Both libraries are BSD and GPL licensed. Linux kernel modules are GPL
licensed.
+Currently supported by DPDK:
+
+- Mellanox OFED **3.4-1.0.0.0**.
+
+- firmware version:
+
+ - ConnectX-4: **12.17.1010**
+ - ConnectX-4 Lx: **14.17.1010**
+
Getting Mellanox OFED
~~~~~~~~~~~~~~~~~~~~~
this DPDK release was developed and tested against is strongly
recommended. Please check the `prerequisites`_.
+Notes for testpmd
+-----------------
+
+Compared to librte_pmd_mlx4 that implements a single RSS configuration per
+port, librte_pmd_mlx5 supports per-protocol RSS configuration.
+
+Since ``testpmd`` defaults to IP RSS mode and there is currently no
+command-line parameter to enable additional protocols (UDP and TCP as well
+as IP), the following commands must be entered from its CLI to get the same
+behavior as librte_pmd_mlx4:
+
+.. code-block:: console
+
+ > port stop all
+ > port config all rss all
+ > port start all
+
Usage example
-------------
modprobe -a ib_uverbs mlx5_core mlx5_ib
+ Alternatively if MLNX_OFED is fully installed, the following script can
+ be run:
+
+ .. code-block:: console
+
+ /etc/init.d/openibd restart
+
.. note::
User space I/O kernel modules (uio and igb_uio) are not used and do
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