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30 MLX4 poll mode driver library
31 =============================
33 The MLX4 poll mode driver library (**librte_pmd_mlx4**) implements support
34 for **Mellanox ConnectX-3** and **Mellanox ConnectX-3 Pro** 10/40 Gbps adapters
35 as well as their virtual functions (VF) in SR-IOV context.
37 Information and documentation about this family of adapters can be found on
38 the `Mellanox website <http://www.mellanox.com>`_. Help is also provided by
39 the `Mellanox community <http://community.mellanox.com/welcome>`_.
41 There is also a `section dedicated to this poll mode driver
42 <http://www.mellanox.com/page/products_dyn?product_family=209&mtag=pmd_for_dpdk>`_.
46 Due to external dependencies, this driver is disabled by default. It must
47 be enabled manually by setting ``CONFIG_RTE_LIBRTE_MLX4_PMD=y`` and
50 Implementation details
51 ----------------------
53 Most Mellanox ConnectX-3 devices provide two ports but expose a single PCI
54 bus address, thus unlike most drivers, librte_pmd_mlx4 registers itself as a
55 PCI driver that allocates one Ethernet device per detected port.
57 For this reason, one cannot white/blacklist a single port without also
58 white/blacklisting the others on the same device.
60 Besides its dependency on libibverbs (that implies libmlx4 and associated
61 kernel support), librte_pmd_mlx4 relies heavily on system calls for control
62 operations such as querying/updating the MTU and flow control parameters.
64 For security reasons and robustness, this driver only deals with virtual
65 memory addresses. The way resources allocations are handled by the kernel
66 combined with hardware specifications that allow it to handle virtual memory
67 addresses directly ensure that DPDK applications cannot access random
68 physical memory (or memory that does not belong to the current process).
70 This capability allows the PMD to coexist with kernel network interfaces
71 which remain functional, although they stop receiving unicast packets as
72 long as they share the same MAC address.
74 Compiling librte_pmd_mlx4 causes DPDK to be linked against libibverbs.
79 - RSS, also known as RCA, is supported. In this mode the number of
80 configured RX queues must be a power of two.
81 - VLAN filtering is supported.
82 - Link state information is provided.
83 - Promiscuous mode is supported.
84 - All multicast mode is supported.
85 - Multiple MAC addresses (unicast, multicast) can be configured.
86 - Scattered packets are supported for TX and RX.
87 - Inner L3/L4 (IP, TCP and UDP) TX/RX checksum offloading and validation.
88 - Outer L3 (IP) TX/RX checksum offloading and validation for VXLAN frames.
89 - Secondary process TX is supported.
94 - RSS hash key cannot be modified.
95 - RSS RETA cannot be configured
96 - RSS always includes L3 (IPv4/IPv6) and L4 (UDP/TCP). They cannot be
98 - Hardware counters are not implemented (they are software counters).
99 - Secondary process RX is not supported.
107 These options can be modified in the ``.config`` file.
109 - ``CONFIG_RTE_LIBRTE_MLX4_PMD`` (default **n**)
111 Toggle compilation of librte_pmd_mlx4 itself.
113 - ``CONFIG_RTE_LIBRTE_MLX4_DEBUG`` (default **n**)
115 Toggle debugging code and stricter compilation flags. Enabling this option
116 adds additional run-time checks and debugging messages at the cost of
119 - ``CONFIG_RTE_LIBRTE_MLX4_SGE_WR_N`` (default **4**)
121 Number of scatter/gather elements (SGEs) per work request (WR). Lowering
122 this number improves performance but also limits the ability to receive
123 scattered packets (packets that do not fit a single mbuf). The default
124 value is a safe tradeoff.
126 - ``CONFIG_RTE_LIBRTE_MLX4_MAX_INLINE`` (default **0**)
128 Amount of data to be inlined during TX operations. Improves latency but
131 - ``CONFIG_RTE_LIBRTE_MLX4_TX_MP_CACHE`` (default **8**)
133 Maximum number of cached memory pools (MPs) per TX queue. Each MP from
134 which buffers are to be transmitted must be associated to memory regions
135 (MRs). This is a slow operation that must be cached.
137 This value is always 1 for RX queues since they use a single MP.
139 - ``CONFIG_RTE_LIBRTE_MLX4_SOFT_COUNTERS`` (default **1**)
141 Toggle software counters. No counters are available if this option is
142 disabled since hardware counters are not supported.
144 Environment variables
145 ~~~~~~~~~~~~~~~~~~~~~
147 - ``MLX4_INLINE_RECV_SIZE``
149 A nonzero value enables inline receive for packets up to that size. May
150 significantly improve performance in some cases but lower it in
151 others. Requires careful testing.
153 Run-time configuration
154 ~~~~~~~~~~~~~~~~~~~~~~
156 - The only constraint when RSS mode is requested is to make sure the number
157 of RX queues is a power of two. This is a hardware requirement.
159 - librte_pmd_mlx4 brings kernel network interfaces up during initialization
160 because it is affected by their state. Forcing them down prevents packets
163 - **ethtool** operations on related kernel interfaces also affect the PMD.
165 Kernel module parameters
166 ~~~~~~~~~~~~~~~~~~~~~~~~
168 The **mlx4_core** kernel module has several parameters that affect the
169 behavior and/or the performance of librte_pmd_mlx4. Some of them are described
172 - **num_vfs** (integer or triplet, optionally prefixed by device address
175 Create the given number of VFs on the specified devices.
177 - **log_num_mgm_entry_size** (integer)
179 Device-managed flow steering (DMFS) is required by DPDK applications. It is
180 enabled by using a negative value, the last four bits of which have a
183 - **-1**: force device-managed flow steering (DMFS).
184 - **-7**: configure optimized steering mode to improve performance with the
185 following limitation: VLAN filtering is not supported with this mode.
186 This is the recommended mode in case VLAN filter is not needed.
191 This driver relies on external libraries and kernel drivers for resources
192 allocations and initialization. The following dependencies are not part of
193 DPDK and must be installed separately:
197 User space verbs framework used by librte_pmd_mlx4. This library provides
198 a generic interface between the kernel and low-level user space drivers
201 It allows slow and privileged operations (context initialization, hardware
202 resources allocations) to be managed by the kernel and fast operations to
203 never leave user space.
207 Low-level user space driver library for Mellanox ConnectX-3 devices,
208 it is automatically loaded by libibverbs.
210 This library basically implements send/receive calls to the hardware
213 - **Kernel modules** (mlnx-ofed-kernel)
215 They provide the kernel-side verbs API and low level device drivers that
216 manage actual hardware initialization and resources sharing with user
219 Unlike most other PMDs, these modules must remain loaded and bound to
222 - mlx4_core: hardware driver managing Mellanox ConnectX-3 devices.
223 - mlx4_en: Ethernet device driver that provides kernel network interfaces.
224 - mlx4_ib: InifiniBand device driver.
225 - ib_uverbs: user space driver for verbs (entry point for libibverbs).
227 - **Firmware update**
229 Mellanox OFED releases include firmware updates for ConnectX-3 adapters.
231 Because each release provides new features, these updates must be applied to
232 match the kernel modules and libraries they come with.
236 Both libraries are BSD and GPL licensed. Linux kernel modules are GPL
239 Currently supported by DPDK:
241 - Mellanox OFED **3.1**.
242 - Firmware version **2.35.5100** and higher.
243 - Supported architectures: **x86_64** and **POWER8**.
245 Getting Mellanox OFED
246 ~~~~~~~~~~~~~~~~~~~~~
248 While these libraries and kernel modules are available on OpenFabrics
249 Alliance's `website <https://www.openfabrics.org/>`_ and provided by package
250 managers on most distributions, this PMD requires Ethernet extensions that
251 may not be supported at the moment (this is a work in progress).
254 <http://www.mellanox.com/page/products_dyn?product_family=26&mtag=linux_sw_drivers>`_
255 includes the necessary support and should be used in the meantime. For DPDK,
256 only libibverbs, libmlx4, mlnx-ofed-kernel packages and firmware updates are
257 required from that distribution.
261 Several versions of Mellanox OFED are available. Installing the version
262 this DPDK release was developed and tested against is strongly
263 recommended. Please check the `prerequisites`_.
268 This section demonstrates how to launch **testpmd** with Mellanox ConnectX-3
269 devices managed by librte_pmd_mlx4.
271 #. Load the kernel modules:
273 .. code-block:: console
275 modprobe -a ib_uverbs mlx4_en mlx4_core mlx4_ib
277 Alternatively if MLNX_OFED is fully installed, the following script can
280 .. code-block:: console
282 /etc/init.d/openibd restart
286 User space I/O kernel modules (uio and igb_uio) are not used and do
287 not have to be loaded.
289 #. Make sure Ethernet interfaces are in working order and linked to kernel
290 verbs. Related sysfs entries should be present:
292 .. code-block:: console
294 ls -d /sys/class/net/*/device/infiniband_verbs/uverbs* | cut -d / -f 5
298 .. code-block:: console
305 #. Optionally, retrieve their PCI bus addresses for whitelisting:
307 .. code-block:: console
310 for intf in eth2 eth3 eth4 eth5;
312 (cd "/sys/class/net/${intf}/device/" && pwd -P);
315 sed -n 's,.*/\(.*\),-w \1,p'
319 .. code-block:: console
328 There are only two distinct PCI bus addresses because the Mellanox
329 ConnectX-3 adapters installed on this system are dual port.
331 #. Request huge pages:
333 .. code-block:: console
335 echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages/nr_hugepages
337 #. Start testpmd with basic parameters:
339 .. code-block:: console
341 testpmd -c 0xff00 -n 4 -w 0000:83:00.0 -w 0000:84:00.0 -- --rxq=2 --txq=2 -i
345 .. code-block:: console
348 EAL: PCI device 0000:83:00.0 on NUMA socket 1
349 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
350 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_0" (VF: false)
351 PMD: librte_pmd_mlx4: 2 port(s) detected
352 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:b7:50
353 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:b7:51
354 EAL: PCI device 0000:84:00.0 on NUMA socket 1
355 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
356 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_1" (VF: false)
357 PMD: librte_pmd_mlx4: 2 port(s) detected
358 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:ba:b0
359 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:ba:b1
360 Interactive-mode selected
361 Configuring Port 0 (socket 0)
362 PMD: librte_pmd_mlx4: 0x867d60: TX queues number update: 0 -> 2
363 PMD: librte_pmd_mlx4: 0x867d60: RX queues number update: 0 -> 2
364 Port 0: 00:02:C9:B5:B7:50
365 Configuring Port 1 (socket 0)
366 PMD: librte_pmd_mlx4: 0x867da0: TX queues number update: 0 -> 2
367 PMD: librte_pmd_mlx4: 0x867da0: RX queues number update: 0 -> 2
368 Port 1: 00:02:C9:B5:B7:51
369 Configuring Port 2 (socket 0)
370 PMD: librte_pmd_mlx4: 0x867de0: TX queues number update: 0 -> 2
371 PMD: librte_pmd_mlx4: 0x867de0: RX queues number update: 0 -> 2
372 Port 2: 00:02:C9:B5:BA:B0
373 Configuring Port 3 (socket 0)
374 PMD: librte_pmd_mlx4: 0x867e20: TX queues number update: 0 -> 2
375 PMD: librte_pmd_mlx4: 0x867e20: RX queues number update: 0 -> 2
376 Port 3: 00:02:C9:B5:BA:B1
377 Checking link statuses...
378 Port 0 Link Up - speed 10000 Mbps - full-duplex
379 Port 1 Link Up - speed 40000 Mbps - full-duplex
380 Port 2 Link Up - speed 10000 Mbps - full-duplex
381 Port 3 Link Up - speed 40000 Mbps - full-duplex