enic.rst revision 32e04ea0
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29
30ENIC Poll Mode Driver
31=====================
32
33ENIC PMD is the DPDK poll-mode driver for the Cisco System Inc. VIC Ethernet
34NICs. These adapters are also referred to as vNICs below. If you are running
35or would like to run DPDK software applications on Cisco UCS servers using
36Cisco VIC adapters the following documentation is relevant.
37
38How to obtain ENIC PMD integrated DPDK
39--------------------------------------
40
41ENIC PMD support is integrated into the DPDK suite. dpdk-<version>.tar.gz
42should be downloaded from http://dpdk.org
43
44
45Configuration information
46-------------------------
47
48- **DPDK Configuration Parameters**
49
50  The following configuration options are available for the ENIC PMD:
51
52  - **CONFIG_RTE_LIBRTE_ENIC_PMD** (default y): Enables or disables inclusion
53    of the ENIC PMD driver in the DPDK compilation.
54
55  - **CONFIG_RTE_LIBRTE_ENIC_DEBUG** (default n): Enables or disables debug
56    logging within the ENIC PMD driver.
57
58- **vNIC Configuration Parameters**
59
60  - **Number of Queues**
61
62    The maximum number of receive queues (RQs), work queues (WQs) and
63    completion queues (CQs) are configurable on a per vNIC basis
64    through the Cisco UCS Manager (CIMC or UCSM).
65
66    These values should be configured as follows:
67
68    - The number of WQs should be greater or equal to the value of the
69      expected nb_tx_q parameter in the call to the
70      rte_eth_dev_configure()
71
72    - The number of RQs configured in the vNIC should be greater or
73      equal to *twice* the value of the expected nb_rx_q parameter in
74      the call to rte_eth_dev_configure().  With the addition of rx
75      scatter, a pair of RQs on the vnic is needed for each receive
76      queue used by DPDK, even if rx scatter is not being used.
77      Having a vNIC with only 1 RQ is not a valid configuration, and
78      will fail with an error message.
79
80    - The number of CQs should set so that there is one CQ for each
81      WQ, and one CQ for each pair of RQs.
82
83    For example: If the application requires 3 Rx queues, and 3 Tx
84    queues, the vNIC should be configured to have at least 3 WQs, 6
85    RQs (3 pairs), and 6 CQs (3 for use by WQs + 3 for use by the 3
86    pairs of RQs).
87
88  - **Size of Queues**
89
90    Likewise, the number of receive and transmit descriptors are configurable on
91    a per vNIC bases via the UCS Manager and should be greater than or equal to
92    the nb_rx_desc and   nb_tx_desc parameters expected to be used in the calls
93    to rte_eth_rx_queue_setup() and rte_eth_tx_queue_setup() respectively.
94    An application requesting more than the set size will be limited to that
95    size.
96
97    Unless there is a lack of resources due to creating many vNICs, it
98    is recommended that the WQ and RQ sizes be set to the maximum.  This
99    gives the application the greatest amount of flexibility in its
100    queue configuration.
101
102    - *Note*: Since the introduction of rx scatter, for performance
103      reasons, this PMD uses two RQs on the vNIC per receive queue in
104      DPDK.  One RQ holds descriptors for the start of a packet the
105      second RQ holds the descriptors for the rest of the fragments of
106      a packet.  This means that the nb_rx_desc parameter to
107      rte_eth_rx_queue_setup() can be a greater than 4096.  The exact
108      amount will depend on the size of the mbufs being used for
109      receives, and the MTU size.
110
111      For example: If the mbuf size is 2048, and the MTU is 9000, then
112      receiving a full size packet will take 5 descriptors, 1 from the
113      start of packet queue, and 4 from the second queue.  Assuming
114      that the RQ size was set to the maximum of 4096, then the
115      application can specify up to 1024 + 4096 as the nb_rx_desc
116      parameter to rte_eth_rx_queue_setup().
117
118  - **Interrupts**
119
120    Only one interrupt per vNIC interface should be configured in the UCS
121    manager regardless of the number receive/transmit queues. The ENIC PMD
122    uses this interrupt to   get information about errors in the fast path.
123
124Limitations
125-----------
126
127- **VLAN 0 Priority Tagging**
128
129  If a vNIC is configured in TRUNK mode by the UCS manager, the adapter will
130  priority tag egress packets according to 802.1Q if they were not already
131  VLAN tagged by software. If the adapter is connected to a properly configured
132  switch, there will be no unexpected behavior.
133
134  In test setups where an Ethernet port of a Cisco adapter in TRUNK mode is
135  connected point-to-point to another adapter port or connected though a router
136  instead of a switch, all ingress packets will be VLAN tagged. Programs such
137  as l3fwd which do not account for VLAN tags in packets will misbehave. The
138  solution is to enable VLAN stripping on ingress. The follow code fragment is
139  example of how to accomplish this:
140
141.. code-block:: console
142
143     vlan_offload = rte_eth_dev_get_vlan_offload(port);
144     vlan_offload |= ETH_VLAN_STRIP_OFFLOAD;
145     rte_eth_dev_set_vlan_offload(port, vlan_offload);
146
147How to build the suite?
148-----------------------
149The build instructions for the DPDK suite should be followed. By default
150the ENIC PMD library will be built into the DPDK library.
151
152For configuring and using UIO and VFIO frameworks, please refer the
153documentation that comes with DPDK suite.
154
155Supported Cisco VIC adapters
156----------------------------
157
158ENIC PMD supports all recent generations of Cisco VIC adapters including:
159
160- VIC 1280
161- VIC 1240
162- VIC 1225
163- VIC 1285
164- VIC 1225T
165- VIC 1227
166- VIC 1227T
167- VIC 1380
168- VIC 1340
169- VIC 1385
170- VIC 1387
171
172- Flow director features are not supported on generation 1 Cisco VIC adapters
173   (M81KR and P81E)
174
175Supported Operating Systems
176---------------------------
177Any Linux distribution fulfilling the conditions described in Dependencies
178section of DPDK documentation.
179
180Supported features
181------------------
182- Unicast, multicast and broadcast transmission and reception
183- Receive queue polling
184- Port Hardware Statistics
185- Hardware VLAN acceleration
186- IP checksum offload
187- Receive side VLAN stripping
188- Multiple receive and transmit queues
189- Flow Director ADD, UPDATE, DELETE, STATS operation support for IPV4 5-TUPLE
190  flows
191- Promiscuous mode
192- Setting RX VLAN (supported via UCSM/CIMC only)
193- VLAN filtering (supported via UCSM/CIMC only)
194- Execution of application by unprivileged system users
195- IPV4, IPV6 and TCP RSS hashing
196- Scattered Rx
197- MTU update
198
199Known bugs and Unsupported features in this release
200---------------------------------------------------
201- Signature or flex byte based flow direction
202- Drop feature of flow direction
203- VLAN based flow direction
204- non-IPV4 flow direction
205- Setting of extended VLAN
206- UDP RSS hashing
207- MTU update only works if Scattered Rx mode is disabled
208
209Prerequisites
210-------------
211- Prepare the system as recommended by DPDK suite.  This includes environment
212  variables, hugepages configuration, tool-chains and configuration
213- Insert vfio-pci kernel module using the command 'modprobe vfio-pci' if the
214  user wants to use VFIO framework
215- Insert uio kernel module using the command 'modprobe uio' if the user wants
216  to use UIO framework
217- DPDK suite should be configured based on the user's decision to use VFIO or
218  UIO framework
219- If the vNIC device(s) to be used is bound to the kernel mode Ethernet driver
220  (enic), use 'ifconfig' to bring the interface down. The dpdk-devbind.py tool
221  can then be used to unbind the device's bus id from the enic kernel mode
222  driver.
223- Bind the intended vNIC to vfio-pci in case the user wants ENIC PMD to use
224  VFIO framework using dpdk-devbind.py.
225- Bind the intended vNIC to igb_uio in case the user wants ENIC PMD to use
226  UIO framework using dpdk-devbind.py.
227
228At this point the system should be ready to run DPDK applications. Once the
229application runs to completion, the vNIC can be detached from vfio-pci or
230igb_uio if necessary.
231
232Root privilege is required to bind and unbind vNICs to/from VFIO/UIO.
233VFIO framework helps an unprivileged user to run the applications.
234For an unprivileged user to run the applications on DPDK and ENIC PMD,
235it may be necessary to increase the maximum locked memory of the user.
236The following command could be used to do this.
237
238.. code-block:: console
239
240    sudo sh -c "ulimit -l <value in Kilo Bytes>"
241
242The value depends on the memory configuration of the application, DPDK and
243PMD.  Typically, the limit has to be raised to higher than 2GB.
244e.g., 2621440
245
246The compilation of any unused drivers can be disabled using the
247configuration file in config/ directory (e.g., config/common_linuxapp).
248This would help in bringing down the time taken for building the
249libraries and the initialization time of the application.
250
251Additional Reference
252--------------------
253- http://www.cisco.com/c/en/us/products/servers-unified-computing
254
255Contact Information
256-------------------
257Any questions or bugs should be reported to DPDK community and to the ENIC PMD
258maintainers:
259
260- John Daley <johndale@cisco.com>
261- Nelson Escobar <neescoba@cisco.com>
262