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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 EN** 10/40 Gbps adapters as well as their virtual
35 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
52 ``CONFIG_RTE_BUILD_COMBINE_LIBS`` with ``CONFIG_RTE_BUILD_SHARED_LIB``
53 is not supported and thus the compilation will fail with this configuration.
55 Implementation details
56 ----------------------
58 Most Mellanox ConnectX-3 devices provide two ports but expose a single PCI
59 bus address, thus unlike most drivers, librte_pmd_mlx4 registers itself as a
60 PCI driver that allocates one Ethernet device per detected port.
62 For this reason, one cannot white/blacklist a single port without also
63 white/blacklisting the others on the same device.
65 Besides its dependency on libibverbs (that implies libmlx4 and associated
66 kernel support), librte_pmd_mlx4 relies heavily on system calls for control
67 operations such as querying/updating the MTU and flow control parameters.
69 For security reasons and robustness, this driver only deals with virtual
70 memory addresses. The way resources allocations are handled by the kernel
71 combined with hardware specifications that allow it to handle virtual memory
72 addresses directly ensure that DPDK applications cannot access random
73 physical memory (or memory that does not belong to the current process).
75 This capability allows the PMD to coexist with kernel network interfaces
76 which remain functional, although they stop receiving unicast packets as
77 long as they share the same MAC address.
79 Compiling librte_pmd_mlx4 causes DPDK to be linked against libibverbs.
84 - RSS, also known as RCA, is supported. In this mode the number of
85 configured RX queues must be a power of two.
86 - VLAN filtering is supported.
87 - Link state information is provided.
88 - Promiscuous mode is supported.
89 - All multicast mode is supported.
90 - Multiple MAC addresses (unicast, multicast) can be configured.
91 - Scattered packets are supported for TX and RX.
92 - Inner L3/L4 (IP, TCP and UDP) TX/RX checksum offloading and validation.
93 - Outer L3 (IP) TX/RX checksum offloading and validation for VXLAN frames.
94 - Secondary process TX is supported.
99 - RSS hash key cannot be modified.
100 - RSS RETA cannot be configured
101 - RSS always includes L3 (IPv4/IPv6) and L4 (UDP/TCP). They cannot be
103 - Hardware counters are not implemented (they are software counters).
104 - Secondary process RX is not supported
112 These options can be modified in the ``.config`` file.
114 - ``CONFIG_RTE_LIBRTE_MLX4_PMD`` (default **n**)
116 Toggle compilation of librte_pmd_mlx4 itself.
118 - ``CONFIG_RTE_LIBRTE_MLX4_DEBUG`` (default **n**)
120 Toggle debugging code and stricter compilation flags. Enabling this option
121 adds additional run-time checks and debugging messages at the cost of
124 - ``CONFIG_RTE_LIBRTE_MLX4_SGE_WR_N`` (default **4**)
126 Number of scatter/gather elements (SGEs) per work request (WR). Lowering
127 this number improves performance but also limits the ability to receive
128 scattered packets (packets that do not fit a single mbuf). The default
129 value is a safe tradeoff.
131 - ``CONFIG_RTE_LIBRTE_MLX4_MAX_INLINE`` (default **0**)
133 Amount of data to be inlined during TX operations. Improves latency but
136 - ``CONFIG_RTE_LIBRTE_MLX4_TX_MP_CACHE`` (default **8**)
138 Maximum number of cached memory pools (MPs) per TX queue. Each MP from
139 which buffers are to be transmitted must be associated to memory regions
140 (MRs). This is a slow operation that must be cached.
142 This value is always 1 for RX queues since they use a single MP.
144 - ``CONFIG_RTE_LIBRTE_MLX4_SOFT_COUNTERS`` (default **1**)
146 Toggle software counters. No counters are available if this option is
147 disabled since hardware counters are not supported.
149 Environment variables
150 ~~~~~~~~~~~~~~~~~~~~~
152 - ``MLX4_INLINE_RECV_SIZE``
154 A nonzero value enables inline receive for packets up to that size. May
155 significantly improve performance in some cases but lower it in
156 others. Requires careful testing.
158 Run-time configuration
159 ~~~~~~~~~~~~~~~~~~~~~~
161 - The only constraint when RSS mode is requested is to make sure the number
162 of RX queues is a power of two. This is a hardware requirement.
164 - librte_pmd_mlx4 brings kernel network interfaces up during initialization
165 because it is affected by their state. Forcing them down prevents packets
168 - **ethtool** operations on related kernel interfaces also affect the PMD.
170 Kernel module parameters
171 ~~~~~~~~~~~~~~~~~~~~~~~~
173 The **mlx4_core** kernel module has several parameters that affect the
174 behavior and/or the performance of librte_pmd_mlx4. Some of them are described
177 - **num_vfs** (integer or triplet, optionally prefixed by device address
180 Create the given number of VFs on the specified devices.
182 - **log_num_mgm_entry_size** (integer)
184 Device-managed flow steering (DMFS) is required by DPDK applications. It is
185 enabled by using a negative value, the last four bits of which have a
188 - **-1**: force device-managed flow steering (DMFS).
189 - **-7**: configure optimized steering mode to improve performance with the
190 following limitation: VLAN filtering is not supported with this mode.
191 This is the recommended mode in case VLAN filter is not needed.
196 This driver relies on external libraries and kernel drivers for resources
197 allocations and initialization. The following dependencies are not part of
198 DPDK and must be installed separately:
202 User space verbs framework used by librte_pmd_mlx4. This library provides
203 a generic interface between the kernel and low-level user space drivers
206 It allows slow and privileged operations (context initialization, hardware
207 resources allocations) to be managed by the kernel and fast operations to
208 never leave user space.
212 Low-level user space driver library for Mellanox ConnectX-3 devices,
213 it is automatically loaded by libibverbs.
215 This library basically implements send/receive calls to the hardware
218 - **Kernel modules** (mlnx-ofed-kernel)
220 They provide the kernel-side verbs API and low level device drivers that
221 manage actual hardware initialization and resources sharing with user
224 Unlike most other PMDs, these modules must remain loaded and bound to
227 - mlx4_core: hardware driver managing Mellanox ConnectX-3 devices.
228 - mlx4_en: Ethernet device driver that provides kernel network interfaces.
229 - mlx4_ib: InifiniBand device driver.
230 - ib_uverbs: user space driver for verbs (entry point for libibverbs).
232 - **Firmware update**
234 Mellanox OFED releases include firmware updates for ConnectX-3 adapters.
236 Because each release provides new features, these updates must be applied to
237 match the kernel modules and libraries they come with.
241 Both libraries are BSD and GPL licensed. Linux kernel modules are GPL
244 Currently supported by DPDK:
246 - Mellanox OFED **3.1**.
247 - Firmware version **2.35.5100** and higher.
248 - Supported architectures: **x86_64** and **POWER8**.
250 Getting Mellanox OFED
251 ~~~~~~~~~~~~~~~~~~~~~
253 While these libraries and kernel modules are available on OpenFabrics
254 Alliance's `website <https://www.openfabrics.org/>`_ and provided by package
255 managers on most distributions, this PMD requires Ethernet extensions that
256 may not be supported at the moment (this is a work in progress).
259 <http://www.mellanox.com/page/products_dyn?product_family=26&mtag=linux_sw_drivers>`_
260 includes the necessary support and should be used in the meantime. For DPDK,
261 only libibverbs, libmlx4, mlnx-ofed-kernel packages and firmware updates are
262 required from that distribution.
266 Several versions of Mellanox OFED are available. Installing the version
267 this DPDK release was developed and tested against is strongly
268 recommended. Please check the `prerequisites`_.
273 This section demonstrates how to launch **testpmd** with Mellanox ConnectX-3
274 devices managed by librte_pmd_mlx4.
276 #. Load the kernel modules:
278 .. code-block:: console
280 modprobe -a ib_uverbs mlx4_en mlx4_core mlx4_ib
282 Alternatively if MLNX_OFED is fully installed, the follwoing script can
285 .. code-block:: console
287 /etc/init.d/openibd restart
291 User space I/O kernel modules (uio and igb_uio) are not used and do
292 not have to be loaded.
294 #. Make sure Ethernet interfaces are in working order and linked to kernel
295 verbs. Related sysfs entries should be present:
297 .. code-block:: console
299 ls -d /sys/class/net/*/device/infiniband_verbs/uverbs* | cut -d / -f 5
303 .. code-block:: console
310 #. Optionally, retrieve their PCI bus addresses for whitelisting:
312 .. code-block:: console
315 for intf in eth2 eth3 eth4 eth5;
317 (cd "/sys/class/net/${intf}/device/" && pwd -P);
320 sed -n 's,.*/\(.*\),-w \1,p'
324 .. code-block:: console
333 There are only two distinct PCI bus addresses because the Mellanox
334 ConnectX-3 adapters installed on this system are dual port.
336 #. Request huge pages:
338 .. code-block:: console
340 echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages/nr_hugepages
342 #. Start testpmd with basic parameters:
344 .. code-block:: console
346 testpmd -c 0xff00 -n 4 -w 0000:83:00.0 -w 0000:84:00.0 -- --rxq=2 --txq=2 -i
350 .. code-block:: console
353 EAL: PCI device 0000:83:00.0 on NUMA socket 1
354 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
355 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_0" (VF: false)
356 PMD: librte_pmd_mlx4: 2 port(s) detected
357 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:b7:50
358 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:b7:51
359 EAL: PCI device 0000:84:00.0 on NUMA socket 1
360 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
361 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_1" (VF: false)
362 PMD: librte_pmd_mlx4: 2 port(s) detected
363 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:ba:b0
364 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:ba:b1
365 Interactive-mode selected
366 Configuring Port 0 (socket 0)
367 PMD: librte_pmd_mlx4: 0x867d60: TX queues number update: 0 -> 2
368 PMD: librte_pmd_mlx4: 0x867d60: RX queues number update: 0 -> 2
369 Port 0: 00:02:C9:B5:B7:50
370 Configuring Port 1 (socket 0)
371 PMD: librte_pmd_mlx4: 0x867da0: TX queues number update: 0 -> 2
372 PMD: librte_pmd_mlx4: 0x867da0: RX queues number update: 0 -> 2
373 Port 1: 00:02:C9:B5:B7:51
374 Configuring Port 2 (socket 0)
375 PMD: librte_pmd_mlx4: 0x867de0: TX queues number update: 0 -> 2
376 PMD: librte_pmd_mlx4: 0x867de0: RX queues number update: 0 -> 2
377 Port 2: 00:02:C9:B5:BA:B0
378 Configuring Port 3 (socket 0)
379 PMD: librte_pmd_mlx4: 0x867e20: TX queues number update: 0 -> 2
380 PMD: librte_pmd_mlx4: 0x867e20: RX queues number update: 0 -> 2
381 Port 3: 00:02:C9:B5:BA:B1
382 Checking link statuses...
383 Port 0 Link Up - speed 10000 Mbps - full-duplex
384 Port 1 Link Up - speed 40000 Mbps - full-duplex
385 Port 2 Link Up - speed 10000 Mbps - full-duplex
386 Port 3 Link Up - speed 40000 Mbps - full-duplex