+ descriptor. Instead, the packet is included with pointer. This parameter
+ is deprecated and converted directly to ``txq_inline_mpw`` providing full
+ compatibility. Valid only if eMPW feature is engaged.
+
+- ``txq_mpw_en`` parameter [int]
+
+ A nonzero value enables Enhanced Multi-Packet Write (eMPW) for ConnectX-5,
+ ConnectX-6, ConnectX-6 Dx and BlueField. eMPW allows the TX burst function to pack
+ up multiple packets in a single descriptor session in order to save PCI bandwidth
+ and improve performance at the cost of a slightly higher CPU usage. When
+ ``txq_inline_mpw`` is set along with ``txq_mpw_en``, TX burst function copies
+ entire packet data on to TX descriptor instead of including pointer of packet.
+
+ The Enhanced Multi-Packet Write feature is enabled by default if NIC supports
+ it, can be disabled by explicit specifying 0 value for ``txq_mpw_en`` option.
+ Also, if minimal data inlining is requested by non-zero ``txq_inline_min``
+ option or reported by the NIC, the eMPW feature is disengaged.
+
+- ``tx_db_nc`` parameter [int]
+
+ The rdma core library can map doorbell register in two ways, depending on the
+ environment variable "MLX5_SHUT_UP_BF":
+
+ - As regular cached memory (usually with write combining attribute), if the
+ variable is either missing or set to zero.
+ - As non-cached memory, if the variable is present and set to not "0" value.
+
+ The type of mapping may slightly affect the Tx performance, the optimal choice
+ is strongly relied on the host architecture and should be deduced practically.
+
+ If ``tx_db_nc`` is set to zero, the doorbell is forced to be mapped to regular
+ memory (with write combining), the PMD will perform the extra write memory barrier
+ after writing to doorbell, it might increase the needed CPU clocks per packet
+ to send, but latency might be improved.
+
+ If ``tx_db_nc`` is set to one, the doorbell is forced to be mapped to non
+ cached memory, the PMD will not perform the extra write memory barrier
+ after writing to doorbell, on some architectures it might improve the
+ performance.
+
+ If ``tx_db_nc`` is set to two, the doorbell is forced to be mapped to regular
+ memory, the PMD will use heuristics to decide whether write memory barrier
+ should be performed. For bursts with size multiple of recommended one (64 pkts)
+ it is supposed the next burst is coming and no need to issue the extra memory
+ barrier (it is supposed to be issued in the next coming burst, at least after
+ descriptor writing). It might increase latency (on some hosts till next
+ packets transmit) and should be used with care.
+
+ If ``tx_db_nc`` is omitted or set to zero, the preset (if any) environment
+ variable "MLX5_SHUT_UP_BF" value is used. If there is no "MLX5_SHUT_UP_BF",
+ the default ``tx_db_nc`` value is zero for ARM64 hosts and one for others.
+
+- ``tx_pp`` parameter [int]
+
+ If a nonzero value is specified the driver creates all necessary internal
+ objects to provide accurate packet send scheduling on mbuf timestamps.
+ The positive value specifies the scheduling granularity in nanoseconds,
+ the packet send will be accurate up to specified digits. The allowed range is
+ from 500 to 1 million of nanoseconds. The negative value specifies the module
+ of granularity and engages the special test mode the check the schedule rate.
+ By default (if the ``tx_pp`` is not specified) send scheduling on timestamps
+ feature is disabled.
+
+- ``tx_skew`` parameter [int]
+
+ The parameter adjusts the send packet scheduling on timestamps and represents
+ the average delay between beginning of the transmitting descriptor processing
+ by the hardware and appearance of actual packet data on the wire. The value
+ should be provided in nanoseconds and is valid only if ``tx_pp`` parameter is
+ specified. The default value is zero.
+
+- ``tx_vec_en`` parameter [int]
+
+ A nonzero value enables Tx vector on ConnectX-5, ConnectX-6, ConnectX-6 Dx
+ and BlueField NICs if the number of global Tx queues on the port is less than
+ ``txqs_max_vec``. The parameter is deprecated and ignored.
+
+- ``rx_vec_en`` parameter [int]
+
+ A nonzero value enables Rx vector if the port is not configured in
+ multi-segment otherwise this parameter is ignored.
+
+ Enabled by default.
+
+- ``vf_nl_en`` parameter [int]
+
+ A nonzero value enables Netlink requests from the VF to add/remove MAC
+ addresses or/and enable/disable promiscuous/all multicast on the Netdevice.
+ Otherwise the relevant configuration must be run with Linux iproute2 tools.
+ This is a prerequisite to receive this kind of traffic.
+
+ Enabled by default, valid only on VF devices ignored otherwise.
+
+- ``l3_vxlan_en`` parameter [int]
+
+ A nonzero value allows L3 VXLAN and VXLAN-GPE flow creation. To enable
+ L3 VXLAN or VXLAN-GPE, users has to configure firmware and enable this
+ parameter. This is a prerequisite to receive this kind of traffic.
+
+ Disabled by default.
+
+- ``dv_xmeta_en`` parameter [int]
+
+ A nonzero value enables extensive flow metadata support if device is
+ capable and driver supports it. This can enable extensive support of
+ ``MARK`` and ``META`` item of ``rte_flow``. The newly introduced
+ ``SET_TAG`` and ``SET_META`` actions do not depend on ``dv_xmeta_en``.
+
+ There are some possible configurations, depending on parameter value:
+
+ - 0, this is default value, defines the legacy mode, the ``MARK`` and
+ ``META`` related actions and items operate only within NIC Tx and
+ NIC Rx steering domains, no ``MARK`` and ``META`` information crosses
+ the domain boundaries. The ``MARK`` item is 24 bits wide, the ``META``
+ item is 32 bits wide and match supported on egress only.
+
+ - 1, this engages extensive metadata mode, the ``MARK`` and ``META``
+ related actions and items operate within all supported steering domains,
+ including FDB, ``MARK`` and ``META`` information may cross the domain
+ boundaries. The ``MARK`` item is 24 bits wide, the ``META`` item width
+ depends on kernel and firmware configurations and might be 0, 16 or
+ 32 bits. Within NIC Tx domain ``META`` data width is 32 bits for
+ compatibility, the actual width of data transferred to the FDB domain
+ depends on kernel configuration and may be vary. The actual supported
+ width can be retrieved in runtime by series of rte_flow_validate()
+ trials.
+
+ - 2, this engages extensive metadata mode, the ``MARK`` and ``META``
+ related actions and items operate within all supported steering domains,
+ including FDB, ``MARK`` and ``META`` information may cross the domain
+ boundaries. The ``META`` item is 32 bits wide, the ``MARK`` item width
+ depends on kernel and firmware configurations and might be 0, 16 or
+ 24 bits. The actual supported width can be retrieved in runtime by
+ series of rte_flow_validate() trials.
+
+ +------+-----------+-----------+-------------+-------------+
+ | Mode | ``MARK`` | ``META`` | ``META`` Tx | FDB/Through |
+ +======+===========+===========+=============+=============+
+ | 0 | 24 bits | 32 bits | 32 bits | no |
+ +------+-----------+-----------+-------------+-------------+
+ | 1 | 24 bits | vary 0-32 | 32 bits | yes |
+ +------+-----------+-----------+-------------+-------------+
+ | 2 | vary 0-32 | 32 bits | 32 bits | yes |
+ +------+-----------+-----------+-------------+-------------+
+
+ If there is no E-Switch configuration the ``dv_xmeta_en`` parameter is
+ ignored and the device is configured to operate in legacy mode (0).
+
+ Disabled by default (set to 0).
+
+ The Direct Verbs/Rules (engaged with ``dv_flow_en`` = 1) supports all
+ of the extensive metadata features. The legacy Verbs supports FLAG and
+ MARK metadata actions over NIC Rx steering domain only.
+
+- ``dv_flow_en`` parameter [int]
+
+ A nonzero value enables the DV flow steering assuming it is supported
+ by the driver (RDMA Core library version is rdma-core-24.0 or higher).
+
+ Enabled by default if supported.
+
+- ``dv_esw_en`` parameter [int]
+
+ A nonzero value enables E-Switch using Direct Rules.
+
+ Enabled by default if supported.
+
+- ``lacp_by_user`` parameter [int]
+
+ A nonzero value enables the control of LACP traffic by the user application.
+ When a bond exists in the driver, by default it should be managed by the
+ kernel and therefore LACP traffic should be steered to the kernel.
+ If this devarg is set to 1 it will allow the user to manage the bond by
+ itself and not steer LACP traffic to the kernel.
+
+ Disabled by default (set to 0).
+
+- ``mr_ext_memseg_en`` parameter [int]
+
+ A nonzero value enables extending memseg when registering DMA memory. If
+ enabled, the number of entries in MR (Memory Region) lookup table on datapath
+ is minimized and it benefits performance. On the other hand, it worsens memory
+ utilization because registered memory is pinned by kernel driver. Even if a
+ page in the extended chunk is freed, that doesn't become reusable until the
+ entire memory is freed.
+
+ Enabled by default.
+
+- ``representor`` parameter [list]
+
+ This parameter can be used to instantiate DPDK Ethernet devices from
+ existing port (or VF) representors configured on the device.
+
+ It is a standard parameter whose format is described in
+ :ref:`ethernet_device_standard_device_arguments`.
+
+ For instance, to probe port representors 0 through 2::
+
+ representor=[0-2]
+
+- ``max_dump_files_num`` parameter [int]
+
+ The maximum number of files per PMD entity that may be created for debug information.
+ The files will be created in /var/log directory or in current directory.
+
+ set to 128 by default.
+
+- ``lro_timeout_usec`` parameter [int]
+
+ The maximum allowed duration of an LRO session, in micro-seconds.
+ PMD will set the nearest value supported by HW, which is not bigger than
+ the input ``lro_timeout_usec`` value.
+ If this parameter is not specified, by default PMD will set
+ the smallest value supported by HW.
+
+- ``hp_buf_log_sz`` parameter [int]
+
+ The total data buffer size of a hairpin queue (logarithmic form), in bytes.
+ PMD will set the data buffer size to 2 ** ``hp_buf_log_sz``, both for RX & TX.
+ The capacity of the value is specified by the firmware and the initialization
+ will get a failure if it is out of scope.
+ The range of the value is from 11 to 19 right now, and the supported frame
+ size of a single packet for hairpin is from 512B to 128KB. It might change if
+ different firmware release is being used. By using a small value, it could
+ reduce memory consumption but not work with a large frame. If the value is
+ too large, the memory consumption will be high and some potential performance
+ degradation will be introduced.
+ By default, the PMD will set this value to 16, which means that 9KB jumbo
+ frames will be supported.