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31 MLX4 poll mode driver library
32 =============================
34 The MLX4 poll mode driver library (**librte_pmd_mlx4**) implements support
35 for **Mellanox ConnectX-3** and **Mellanox ConnectX-3 Pro** 10/40 Gbps adapters
36 as well as their virtual functions (VF) in SR-IOV context.
38 Information and documentation about this family of adapters can be found on
39 the `Mellanox website <http://www.mellanox.com>`_. Help is also provided by
40 the `Mellanox community <http://community.mellanox.com/welcome>`_.
42 There is also a `section dedicated to this poll mode driver
43 <http://www.mellanox.com/page/products_dyn?product_family=209&mtag=pmd_for_dpdk>`_.
47 Due to external dependencies, this driver is disabled by default. It must
48 be enabled manually by setting ``CONFIG_RTE_LIBRTE_MLX4_PMD=y`` and
51 Implementation details
52 ----------------------
54 Most Mellanox ConnectX-3 devices provide two ports but expose a single PCI
55 bus address, thus unlike most drivers, librte_pmd_mlx4 registers itself as a
56 PCI driver that allocates one Ethernet device per detected port.
58 For this reason, one cannot white/blacklist a single port without also
59 white/blacklisting the others on the same device.
61 Besides its dependency on libibverbs (that implies libmlx4 and associated
62 kernel support), librte_pmd_mlx4 relies heavily on system calls for control
63 operations such as querying/updating the MTU and flow control parameters.
65 For security reasons and robustness, this driver only deals with virtual
66 memory addresses. The way resources allocations are handled by the kernel
67 combined with hardware specifications that allow it to handle virtual memory
68 addresses directly ensure that DPDK applications cannot access random
69 physical memory (or memory that does not belong to the current process).
71 This capability allows the PMD to coexist with kernel network interfaces
72 which remain functional, although they stop receiving unicast packets as
73 long as they share the same MAC address.
75 Compiling librte_pmd_mlx4 causes DPDK to be linked against libibverbs.
80 - Multi arch support: x86_64 and POWER8.
81 - RSS, also known as RCA, is supported. In this mode the number of
82 configured RX queues must be a power of two.
83 - VLAN filtering is supported.
84 - Link state information is provided.
85 - Promiscuous mode is supported.
86 - All multicast mode is supported.
87 - Multiple MAC addresses (unicast, multicast) can be configured.
88 - Scattered packets are supported for TX and RX.
89 - Inner L3/L4 (IP, TCP and UDP) TX/RX checksum offloading and validation.
90 - Outer L3 (IP) TX/RX checksum offloading and validation for VXLAN frames.
91 - Secondary process TX is supported.
97 - RSS hash key cannot be modified.
98 - RSS RETA cannot be configured
99 - RSS always includes L3 (IPv4/IPv6) and L4 (UDP/TCP). They cannot be
101 - Hardware counters are not implemented (they are software counters).
102 - Secondary process RX is not supported.
110 These options can be modified in the ``.config`` file.
112 - ``CONFIG_RTE_LIBRTE_MLX4_PMD`` (default **n**)
114 Toggle compilation of librte_pmd_mlx4 itself.
116 - ``CONFIG_RTE_LIBRTE_MLX4_DEBUG`` (default **n**)
118 Toggle debugging code and stricter compilation flags. Enabling this option
119 adds additional run-time checks and debugging messages at the cost of
122 - ``CONFIG_RTE_LIBRTE_MLX4_DEBUG_BROKEN_VERBS`` (default **n**)
124 Mellanox OFED versions earlier than 4.2 may return false errors from
125 Verbs object destruction APIs after the device is plugged out.
126 Enabling this option replaces assertion checks that cause the program
127 to abort with harmless debugging messages as a workaround.
128 Relevant only when CONFIG_RTE_LIBRTE_MLX4_DEBUG is enabled.
130 - ``CONFIG_RTE_LIBRTE_MLX4_SGE_WR_N`` (default **4**)
132 Number of scatter/gather elements (SGEs) per work request (WR). Lowering
133 this number improves performance but also limits the ability to receive
134 scattered packets (packets that do not fit a single mbuf). The default
135 value is a safe tradeoff.
137 - ``CONFIG_RTE_LIBRTE_MLX4_MAX_INLINE`` (default **0**)
139 Amount of data to be inlined during TX operations. Improves latency but
142 - ``CONFIG_RTE_LIBRTE_MLX4_TX_MP_CACHE`` (default **8**)
144 Maximum number of cached memory pools (MPs) per TX queue. Each MP from
145 which buffers are to be transmitted must be associated to memory regions
146 (MRs). This is a slow operation that must be cached.
148 This value is always 1 for RX queues since they use a single MP.
150 - ``CONFIG_RTE_LIBRTE_MLX4_SOFT_COUNTERS`` (default **1**)
152 Toggle software counters. No counters are available if this option is
153 disabled since hardware counters are not supported.
155 Environment variables
156 ~~~~~~~~~~~~~~~~~~~~~
158 - ``MLX4_INLINE_RECV_SIZE``
160 A nonzero value enables inline receive for packets up to that size. May
161 significantly improve performance in some cases but lower it in
162 others. Requires careful testing.
164 Run-time configuration
165 ~~~~~~~~~~~~~~~~~~~~~~
167 - The only constraint when RSS mode is requested is to make sure the number
168 of RX queues is a power of two. This is a hardware requirement.
170 - librte_pmd_mlx4 brings kernel network interfaces up during initialization
171 because it is affected by their state. Forcing them down prevents packets
174 - **ethtool** operations on related kernel interfaces also affect the PMD.
176 - ``port`` parameter [int]
178 This parameter provides a physical port to probe and can be specified multiple
179 times for additional ports. All ports are probed by default if left
182 Kernel module parameters
183 ~~~~~~~~~~~~~~~~~~~~~~~~
185 The **mlx4_core** kernel module has several parameters that affect the
186 behavior and/or the performance of librte_pmd_mlx4. Some of them are described
189 - **num_vfs** (integer or triplet, optionally prefixed by device address
192 Create the given number of VFs on the specified devices.
194 - **log_num_mgm_entry_size** (integer)
196 Device-managed flow steering (DMFS) is required by DPDK applications. It is
197 enabled by using a negative value, the last four bits of which have a
200 - **-1**: force device-managed flow steering (DMFS).
201 - **-7**: configure optimized steering mode to improve performance with the
202 following limitation: VLAN filtering is not supported with this mode.
203 This is the recommended mode in case VLAN filter is not needed.
208 This driver relies on external libraries and kernel drivers for resources
209 allocations and initialization. The following dependencies are not part of
210 DPDK and must be installed separately:
214 User space verbs framework used by librte_pmd_mlx4. This library provides
215 a generic interface between the kernel and low-level user space drivers
218 It allows slow and privileged operations (context initialization, hardware
219 resources allocations) to be managed by the kernel and fast operations to
220 never leave user space.
224 Low-level user space driver library for Mellanox ConnectX-3 devices,
225 it is automatically loaded by libibverbs.
227 This library basically implements send/receive calls to the hardware
230 - **Kernel modules** (mlnx-ofed-kernel)
232 They provide the kernel-side verbs API and low level device drivers that
233 manage actual hardware initialization and resources sharing with user
236 Unlike most other PMDs, these modules must remain loaded and bound to
239 - mlx4_core: hardware driver managing Mellanox ConnectX-3 devices.
240 - mlx4_en: Ethernet device driver that provides kernel network interfaces.
241 - mlx4_ib: InifiniBand device driver.
242 - ib_uverbs: user space driver for verbs (entry point for libibverbs).
244 - **Firmware update**
246 Mellanox OFED releases include firmware updates for ConnectX-3 adapters.
248 Because each release provides new features, these updates must be applied to
249 match the kernel modules and libraries they come with.
253 Both libraries are BSD and GPL licensed. Linux kernel modules are GPL
256 Currently supported by DPDK:
258 - Mellanox OFED **4.1**.
259 - Firmware version **2.36.5000** and above.
261 Getting Mellanox OFED
262 ~~~~~~~~~~~~~~~~~~~~~
264 While these libraries and kernel modules are available on OpenFabrics
265 Alliance's `website <https://www.openfabrics.org/>`_ and provided by package
266 managers on most distributions, this PMD requires Ethernet extensions that
267 may not be supported at the moment (this is a work in progress).
270 <http://www.mellanox.com/page/products_dyn?product_family=26&mtag=linux_sw_drivers>`_
271 includes the necessary support and should be used in the meantime. For DPDK,
272 only libibverbs, libmlx4, mlnx-ofed-kernel packages and firmware updates are
273 required from that distribution.
277 Several versions of Mellanox OFED are available. Installing the version
278 this DPDK release was developed and tested against is strongly
279 recommended. Please check the `prerequisites`_.
284 * Mellanox(R) ConnectX(R)-3 Pro 40G MCX354A-FCC_Ax (2*40G)
289 1. Download latest Mellanox OFED. For more info check the `prerequisites`_.
291 2. Install the required libraries and kernel modules either by installing
292 only the required set, or by installing the entire Mellanox OFED:
296 .. code-block:: console
300 For SR-IOV hypervisors use:
302 .. code-block:: console
304 ./mlnxofedinstall --enable-sriov -hypervisor
306 For SR-IOV virtual machine use:
308 .. code-block:: console
310 ./mlnxofedinstall --guest
312 3. Verify the firmware is the correct one:
314 .. code-block:: console
318 4. Set all ports links to Ethernet, follow instructions on the screen:
320 .. code-block:: console
324 Or in the manual way:
326 .. code-block:: console
328 PCI=<NIC PCI address>
329 echo eth > "/sys/bus/pci/devices/$PCI/mlx4_port0"
330 echo eth > "/sys/bus/pci/devices/$PCI/mlx4_port1"
332 5. In case of bare metal or hypervisor, configure optimized steering mode
333 by adding the following line to ``/etc/modprobe.d/mlx4_core.conf``:
335 .. code-block:: console
337 options mlx4_core log_num_mgm_entry_size=-7
341 If VLAN filtering is used, set log_num_mgm_entry_size=-1.
342 Performance degradation can occur on this case.
344 6. Restart the driver:
346 .. code-block:: console
348 /etc/init.d/openibd restart
352 .. code-block:: console
354 service openibd restart
356 7. Compile DPDK and you are ready to go. See instructions on
357 :ref:`Development Kit Build System <Development_Kit_Build_System>`
362 1. Verify the optimized steering mode is configured:
364 .. code-block:: console
366 cat /sys/module/mlx4_core/parameters/log_num_mgm_entry_size
368 2. Use environment variable MLX4_INLINE_RECV_SIZE=64 to get maximum
369 performance for 64B messages.
371 3. Use the CPU near local NUMA node to which the PCIe adapter is connected,
372 for better performance. For VMs, verify that the right CPU
373 and NUMA node are pinned according to the above. Run:
375 .. code-block:: console
379 to identify the NUMA node to which the PCIe adapter is connected.
381 4. If more than one adapter is used, and root complex capabilities allow
382 to put both adapters on the same NUMA node without PCI bandwidth degradation,
383 it is recommended to locate both adapters on the same NUMA node.
384 This in order to forward packets from one to the other without
385 NUMA performance penalty.
387 5. Disable pause frames:
389 .. code-block:: console
391 ethtool -A <netdev> rx off tx off
393 6. Verify IO non-posted prefetch is disabled by default. This can be checked
394 via the BIOS configuration. Please contact you server provider for more
395 information about the settings.
399 On some machines, depends on the machine integrator, it is beneficial
400 to set the PCI max read request parameter to 1K. This can be
401 done in the following way:
403 To query the read request size use:
405 .. code-block:: console
407 setpci -s <NIC PCI address> 68.w
409 If the output is different than 3XXX, set it by:
411 .. code-block:: console
413 setpci -s <NIC PCI address> 68.w=3XXX
415 The XXX can be different on different systems. Make sure to configure
416 according to the setpci output.
421 This section demonstrates how to launch **testpmd** with Mellanox ConnectX-3
422 devices managed by librte_pmd_mlx4.
424 #. Load the kernel modules:
426 .. code-block:: console
428 modprobe -a ib_uverbs mlx4_en mlx4_core mlx4_ib
430 Alternatively if MLNX_OFED is fully installed, the following script can
433 .. code-block:: console
435 /etc/init.d/openibd restart
439 User space I/O kernel modules (uio and igb_uio) are not used and do
440 not have to be loaded.
442 #. Make sure Ethernet interfaces are in working order and linked to kernel
443 verbs. Related sysfs entries should be present:
445 .. code-block:: console
447 ls -d /sys/class/net/*/device/infiniband_verbs/uverbs* | cut -d / -f 5
451 .. code-block:: console
458 #. Optionally, retrieve their PCI bus addresses for whitelisting:
460 .. code-block:: console
463 for intf in eth2 eth3 eth4 eth5;
465 (cd "/sys/class/net/${intf}/device/" && pwd -P);
468 sed -n 's,.*/\(.*\),-w \1,p'
472 .. code-block:: console
481 There are only two distinct PCI bus addresses because the Mellanox
482 ConnectX-3 adapters installed on this system are dual port.
484 #. Request huge pages:
486 .. code-block:: console
488 echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages/nr_hugepages
490 #. Start testpmd with basic parameters:
492 .. code-block:: console
494 testpmd -l 8-15 -n 4 -w 0000:83:00.0 -w 0000:84:00.0 -- --rxq=2 --txq=2 -i
498 .. code-block:: console
501 EAL: PCI device 0000:83:00.0 on NUMA socket 1
502 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
503 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_0" (VF: false)
504 PMD: librte_pmd_mlx4: 2 port(s) detected
505 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:b7:50
506 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:b7:51
507 EAL: PCI device 0000:84:00.0 on NUMA socket 1
508 EAL: probe driver: 15b3:1007 librte_pmd_mlx4
509 PMD: librte_pmd_mlx4: PCI information matches, using device "mlx4_1" (VF: false)
510 PMD: librte_pmd_mlx4: 2 port(s) detected
511 PMD: librte_pmd_mlx4: port 1 MAC address is 00:02:c9:b5:ba:b0
512 PMD: librte_pmd_mlx4: port 2 MAC address is 00:02:c9:b5:ba:b1
513 Interactive-mode selected
514 Configuring Port 0 (socket 0)
515 PMD: librte_pmd_mlx4: 0x867d60: TX queues number update: 0 -> 2
516 PMD: librte_pmd_mlx4: 0x867d60: RX queues number update: 0 -> 2
517 Port 0: 00:02:C9:B5:B7:50
518 Configuring Port 1 (socket 0)
519 PMD: librte_pmd_mlx4: 0x867da0: TX queues number update: 0 -> 2
520 PMD: librte_pmd_mlx4: 0x867da0: RX queues number update: 0 -> 2
521 Port 1: 00:02:C9:B5:B7:51
522 Configuring Port 2 (socket 0)
523 PMD: librte_pmd_mlx4: 0x867de0: TX queues number update: 0 -> 2
524 PMD: librte_pmd_mlx4: 0x867de0: RX queues number update: 0 -> 2
525 Port 2: 00:02:C9:B5:BA:B0
526 Configuring Port 3 (socket 0)
527 PMD: librte_pmd_mlx4: 0x867e20: TX queues number update: 0 -> 2
528 PMD: librte_pmd_mlx4: 0x867e20: RX queues number update: 0 -> 2
529 Port 3: 00:02:C9:B5:BA:B1
530 Checking link statuses...
531 Port 0 Link Up - speed 10000 Mbps - full-duplex
532 Port 1 Link Up - speed 40000 Mbps - full-duplex
533 Port 2 Link Up - speed 10000 Mbps - full-duplex
534 Port 3 Link Up - speed 40000 Mbps - full-duplex