mlx5.rst revision 97f17497
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29
30MLX5 poll mode driver
31=====================
32
33The MLX5 poll mode driver library (**librte_pmd_mlx5**) provides support for
34**Mellanox ConnectX-4** and **Mellanox ConnectX-4 Lx** families of
3510/25/40/50/100 Gb/s adapters as well as their virtual functions (VF) in
36SR-IOV context.
37
38Information and documentation about these adapters can be found on the
39`Mellanox website <http://www.mellanox.com>`__. Help is also provided by the
40`Mellanox community <http://community.mellanox.com/welcome>`__.
41
42There 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>`__.
44
45.. note::
46
47   Due to external dependencies, this driver is disabled by default. It must
48   be enabled manually by setting ``CONFIG_RTE_LIBRTE_MLX5_PMD=y`` and
49   recompiling DPDK.
50
51Implementation details
52----------------------
53
54Besides its dependency on libibverbs (that implies libmlx5 and associated
55kernel support), librte_pmd_mlx5 relies heavily on system calls for control
56operations such as querying/updating the MTU and flow control parameters.
57
58For security reasons and robustness, this driver only deals with virtual
59memory addresses. The way resources allocations are handled by the kernel
60combined with hardware specifications that allow it to handle virtual memory
61addresses directly ensure that DPDK applications cannot access random
62physical memory (or memory that does not belong to the current process).
63
64This capability allows the PMD to coexist with kernel network interfaces
65which remain functional, although they stop receiving unicast packets as
66long as they share the same MAC address.
67
68Enabling librte_pmd_mlx5 causes DPDK applications to be linked against
69libibverbs.
70
71Features
72--------
73
74- Multiple TX and RX queues.
75- Support for scattered TX and RX frames.
76- IPv4, IPv6, TCPv4, TCPv6, UDPv4 and UDPv6 RSS on any number of queues.
77- Several RSS hash keys, one for each flow type.
78- Configurable RETA table.
79- Support for multiple MAC addresses.
80- VLAN filtering.
81- RX VLAN stripping.
82- TX VLAN insertion.
83- RX CRC stripping configuration.
84- Promiscuous mode.
85- Multicast promiscuous mode.
86- Hardware checksum offloads.
87- Flow director (RTE_FDIR_MODE_PERFECT and RTE_FDIR_MODE_PERFECT_MAC_VLAN).
88- Secondary process TX is supported.
89
90Limitations
91-----------
92
93- KVM and VMware ESX SR-IOV modes are not supported yet.
94- Inner RSS for VXLAN frames is not supported yet.
95- Port statistics through software counters only.
96- Hardware checksum offloads for VXLAN inner header are not supported yet.
97- Secondary process RX is not supported.
98
99Configuration
100-------------
101
102Compilation options
103~~~~~~~~~~~~~~~~~~~
104
105These options can be modified in the ``.config`` file.
106
107- ``CONFIG_RTE_LIBRTE_MLX5_PMD`` (default **n**)
108
109  Toggle compilation of librte_pmd_mlx5 itself.
110
111- ``CONFIG_RTE_LIBRTE_MLX5_DEBUG`` (default **n**)
112
113  Toggle debugging code and stricter compilation flags. Enabling this option
114  adds additional run-time checks and debugging messages at the cost of
115  lower performance.
116
117- ``CONFIG_RTE_LIBRTE_MLX5_SGE_WR_N`` (default **4**)
118
119  Number of scatter/gather elements (SGEs) per work request (WR). Lowering
120  this number improves performance but also limits the ability to receive
121  scattered packets (packets that do not fit a single mbuf). The default
122  value is a safe tradeoff.
123
124- ``CONFIG_RTE_LIBRTE_MLX5_MAX_INLINE`` (default **0**)
125
126  Amount of data to be inlined during TX operations. Improves latency.
127  Can improve PPS performance when PCI backpressure is detected and may be
128  useful for scenarios involving heavy traffic on many queues.
129
130  Since the additional software logic necessary to handle this mode can
131  lower performance when there is no backpressure, it is not enabled by
132  default.
133
134- ``CONFIG_RTE_LIBRTE_MLX5_TX_MP_CACHE`` (default **8**)
135
136  Maximum number of cached memory pools (MPs) per TX queue. Each MP from
137  which buffers are to be transmitted must be associated to memory regions
138  (MRs). This is a slow operation that must be cached.
139
140  This value is always 1 for RX queues since they use a single MP.
141
142Environment variables
143~~~~~~~~~~~~~~~~~~~~~
144
145- ``MLX5_ENABLE_CQE_COMPRESSION``
146
147  A nonzero value lets ConnectX-4 return smaller completion entries to
148  improve performance when PCI backpressure is detected. It is most useful
149  for scenarios involving heavy traffic on many queues.
150
151  Since the additional software logic necessary to handle this mode can
152  lower performance when there is no backpressure, it is not enabled by
153  default.
154
155- ``MLX5_PMD_ENABLE_PADDING``
156
157  Enables HW packet padding in PCI bus transactions.
158
159  When packet size is cache aligned and CRC stripping is enabled, 4 fewer
160  bytes are written to the PCI bus. Enabling padding makes such packets
161  aligned again.
162
163  In cases where PCI bandwidth is the bottleneck, padding can improve
164  performance by 10%.
165
166  This is disabled by default since this can also decrease performance for
167  unaligned packet sizes.
168
169Run-time configuration
170~~~~~~~~~~~~~~~~~~~~~~
171
172- librte_pmd_mlx5 brings kernel network interfaces up during initialization
173  because it is affected by their state. Forcing them down prevents packets
174  reception.
175
176- **ethtool** operations on related kernel interfaces also affect the PMD.
177
178Prerequisites
179-------------
180
181This driver relies on external libraries and kernel drivers for resources
182allocations and initialization. The following dependencies are not part of
183DPDK and must be installed separately:
184
185- **libibverbs**
186
187  User space Verbs framework used by librte_pmd_mlx5. This library provides
188  a generic interface between the kernel and low-level user space drivers
189  such as libmlx5.
190
191  It allows slow and privileged operations (context initialization, hardware
192  resources allocations) to be managed by the kernel and fast operations to
193  never leave user space.
194
195- **libmlx5**
196
197  Low-level user space driver library for Mellanox ConnectX-4 devices,
198  it is automatically loaded by libibverbs.
199
200  This library basically implements send/receive calls to the hardware
201  queues.
202
203- **Kernel modules** (mlnx-ofed-kernel)
204
205  They provide the kernel-side Verbs API and low level device drivers that
206  manage actual hardware initialization and resources sharing with user
207  space processes.
208
209  Unlike most other PMDs, these modules must remain loaded and bound to
210  their devices:
211
212  - mlx5_core: hardware driver managing Mellanox ConnectX-4 devices and
213    related Ethernet kernel network devices.
214  - mlx5_ib: InifiniBand device driver.
215  - ib_uverbs: user space driver for Verbs (entry point for libibverbs).
216
217- **Firmware update**
218
219  Mellanox OFED releases include firmware updates for ConnectX-4 adapters.
220
221  Because each release provides new features, these updates must be applied to
222  match the kernel modules and libraries they come with.
223
224.. note::
225
226   Both libraries are BSD and GPL licensed. Linux kernel modules are GPL
227   licensed.
228
229Currently supported by DPDK:
230
231- Mellanox OFED **3.1-1.0.3**, **3.1-1.5.7.1** or **3.2-2.0.0.0** depending
232  on usage.
233
234    The following features are supported with version **3.1-1.5.7.1** and
235    above only:
236
237    - IPv6, UPDv6, TCPv6 RSS.
238    - RX checksum offloads.
239    - IBM POWER8.
240
241    The following features are supported with version **3.2-2.0.0.0** and
242    above only:
243
244    - Flow director.
245    - RX VLAN stripping.
246    - TX VLAN insertion.
247    - RX CRC stripping configuration.
248
249- Minimum firmware version:
250
251  With MLNX_OFED **3.1-1.0.3**:
252
253  - ConnectX-4: **12.12.1240**
254  - ConnectX-4 Lx: **14.12.1100**
255
256  With MLNX_OFED **3.1-1.5.7.1**:
257
258  - ConnectX-4: **12.13.0144**
259  - ConnectX-4 Lx: **14.13.0144**
260
261  With MLNX_OFED **3.2-2.0.0.0**:
262
263  - ConnectX-4: **12.14.2036**
264  - ConnectX-4 Lx: **14.14.2036**
265
266Getting Mellanox OFED
267~~~~~~~~~~~~~~~~~~~~~
268
269While these libraries and kernel modules are available on OpenFabrics
270Alliance's `website <https://www.openfabrics.org/>`__ and provided by package
271managers on most distributions, this PMD requires Ethernet extensions that
272may not be supported at the moment (this is a work in progress).
273
274`Mellanox OFED
275<http://www.mellanox.com/page/products_dyn?product_family=26&mtag=linux>`__
276includes the necessary support and should be used in the meantime. For DPDK,
277only libibverbs, libmlx5, mlnx-ofed-kernel packages and firmware updates are
278required from that distribution.
279
280.. note::
281
282   Several versions of Mellanox OFED are available. Installing the version
283   this DPDK release was developed and tested against is strongly
284   recommended. Please check the `prerequisites`_.
285
286Notes for testpmd
287-----------------
288
289Compared to librte_pmd_mlx4 that implements a single RSS configuration per
290port, librte_pmd_mlx5 supports per-protocol RSS configuration.
291
292Since ``testpmd`` defaults to IP RSS mode and there is currently no
293command-line parameter to enable additional protocols (UDP and TCP as well
294as IP), the following commands must be entered from its CLI to get the same
295behavior as librte_pmd_mlx4:
296
297.. code-block:: console
298
299   > port stop all
300   > port config all rss all
301   > port start all
302
303Usage example
304-------------
305
306This section demonstrates how to launch **testpmd** with Mellanox ConnectX-4
307devices managed by librte_pmd_mlx5.
308
309#. Load the kernel modules:
310
311   .. code-block:: console
312
313      modprobe -a ib_uverbs mlx5_core mlx5_ib
314
315   Alternatively if MLNX_OFED is fully installed, the following script can
316   be run:
317
318   .. code-block:: console
319
320      /etc/init.d/openibd restart
321
322   .. note::
323
324      User space I/O kernel modules (uio and igb_uio) are not used and do
325      not have to be loaded.
326
327#. Make sure Ethernet interfaces are in working order and linked to kernel
328   verbs. Related sysfs entries should be present:
329
330   .. code-block:: console
331
332      ls -d /sys/class/net/*/device/infiniband_verbs/uverbs* | cut -d / -f 5
333
334   Example output:
335
336   .. code-block:: console
337
338      eth30
339      eth31
340      eth32
341      eth33
342
343#. Optionally, retrieve their PCI bus addresses for whitelisting:
344
345   .. code-block:: console
346
347      {
348          for intf in eth2 eth3 eth4 eth5;
349          do
350              (cd "/sys/class/net/${intf}/device/" && pwd -P);
351          done;
352      } |
353      sed -n 's,.*/\(.*\),-w \1,p'
354
355   Example output:
356
357   .. code-block:: console
358
359      -w 0000:05:00.1
360      -w 0000:06:00.0
361      -w 0000:06:00.1
362      -w 0000:05:00.0
363
364#. Request huge pages:
365
366   .. code-block:: console
367
368      echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages/nr_hugepages
369
370#. Start testpmd with basic parameters:
371
372   .. code-block:: console
373
374      testpmd -c 0xff00 -n 4 -w 05:00.0 -w 05:00.1 -w 06:00.0 -w 06:00.1 -- --rxq=2 --txq=2 -i
375
376   Example output:
377
378   .. code-block:: console
379
380      [...]
381      EAL: PCI device 0000:05:00.0 on NUMA socket 0
382      EAL:   probe driver: 15b3:1013 librte_pmd_mlx5
383      PMD: librte_pmd_mlx5: PCI information matches, using device "mlx5_0" (VF: false)
384      PMD: librte_pmd_mlx5: 1 port(s) detected
385      PMD: librte_pmd_mlx5: port 1 MAC address is e4:1d:2d:e7:0c:fe
386      EAL: PCI device 0000:05:00.1 on NUMA socket 0
387      EAL:   probe driver: 15b3:1013 librte_pmd_mlx5
388      PMD: librte_pmd_mlx5: PCI information matches, using device "mlx5_1" (VF: false)
389      PMD: librte_pmd_mlx5: 1 port(s) detected
390      PMD: librte_pmd_mlx5: port 1 MAC address is e4:1d:2d:e7:0c:ff
391      EAL: PCI device 0000:06:00.0 on NUMA socket 0
392      EAL:   probe driver: 15b3:1013 librte_pmd_mlx5
393      PMD: librte_pmd_mlx5: PCI information matches, using device "mlx5_2" (VF: false)
394      PMD: librte_pmd_mlx5: 1 port(s) detected
395      PMD: librte_pmd_mlx5: port 1 MAC address is e4:1d:2d:e7:0c:fa
396      EAL: PCI device 0000:06:00.1 on NUMA socket 0
397      EAL:   probe driver: 15b3:1013 librte_pmd_mlx5
398      PMD: librte_pmd_mlx5: PCI information matches, using device "mlx5_3" (VF: false)
399      PMD: librte_pmd_mlx5: 1 port(s) detected
400      PMD: librte_pmd_mlx5: port 1 MAC address is e4:1d:2d:e7:0c:fb
401      Interactive-mode selected
402      Configuring Port 0 (socket 0)
403      PMD: librte_pmd_mlx5: 0x8cba80: TX queues number update: 0 -> 2
404      PMD: librte_pmd_mlx5: 0x8cba80: RX queues number update: 0 -> 2
405      Port 0: E4:1D:2D:E7:0C:FE
406      Configuring Port 1 (socket 0)
407      PMD: librte_pmd_mlx5: 0x8ccac8: TX queues number update: 0 -> 2
408      PMD: librte_pmd_mlx5: 0x8ccac8: RX queues number update: 0 -> 2
409      Port 1: E4:1D:2D:E7:0C:FF
410      Configuring Port 2 (socket 0)
411      PMD: librte_pmd_mlx5: 0x8cdb10: TX queues number update: 0 -> 2
412      PMD: librte_pmd_mlx5: 0x8cdb10: RX queues number update: 0 -> 2
413      Port 2: E4:1D:2D:E7:0C:FA
414      Configuring Port 3 (socket 0)
415      PMD: librte_pmd_mlx5: 0x8ceb58: TX queues number update: 0 -> 2
416      PMD: librte_pmd_mlx5: 0x8ceb58: RX queues number update: 0 -> 2
417      Port 3: E4:1D:2D:E7:0C:FB
418      Checking link statuses...
419      Port 0 Link Up - speed 40000 Mbps - full-duplex
420      Port 1 Link Up - speed 40000 Mbps - full-duplex
421      Port 2 Link Up - speed 10000 Mbps - full-duplex
422      Port 3 Link Up - speed 10000 Mbps - full-duplex
423      Done
424      testpmd>
425