/usr/share/doc/openvswitch-doc/html/_sources/howto/dpdk.rst.txt is in openvswitch-doc 2.9.0-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 | ..
Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.
Convention for heading levels in Open vSwitch documentation:
======= Heading 0 (reserved for the title in a document)
------- Heading 1
~~~~~~~ Heading 2
+++++++ Heading 3
''''''' Heading 4
Avoid deeper levels because they do not render well.
============================
Using Open vSwitch with DPDK
============================
This document describes how to use Open vSwitch with DPDK datapath.
.. important::
Using the DPDK datapath requires building OVS with DPDK support. Refer to
:doc:`/intro/install/dpdk` for more information.
Ports and Bridges
-----------------
ovs-vsctl can be used to set up bridges and other Open vSwitch features.
Bridges should be created with a ``datapath_type=netdev``::
$ ovs-vsctl add-br br0 -- set bridge br0 datapath_type=netdev
ovs-vsctl can also be used to add DPDK devices. ovs-vswitchd should print the
number of dpdk devices found in the log file::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs=0000:01:00.0
$ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
options:dpdk-devargs=0000:01:00.1
Some NICs (i.e. Mellanox ConnectX-3) have only one PCI address associated
with multiple ports. Using a PCI device like above won't work. Instead, below
usage is suggested::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:01"
$ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:02"
Note: such syntax won't support hotplug. The hotplug is supposed to work with
future DPDK release, v18.05.
After the DPDK ports get added to switch, a polling thread continuously polls
DPDK devices and consumes 100% of the core, as can be checked from ``top`` and
``ps`` commands::
$ top -H
$ ps -eLo pid,psr,comm | grep pmd
Creating bonds of DPDK interfaces is slightly different to creating bonds of
system interfaces. For DPDK, the interface type and devargs must be explicitly
set. For example::
$ ovs-vsctl add-bond br0 dpdkbond p0 p1 \
-- set Interface p0 type=dpdk options:dpdk-devargs=0000:01:00.0 \
-- set Interface p1 type=dpdk options:dpdk-devargs=0000:01:00.1
To stop ovs-vswitchd & delete bridge, run::
$ ovs-appctl -t ovs-vswitchd exit
$ ovs-appctl -t ovsdb-server exit
$ ovs-vsctl del-br br0
PMD Thread Statistics
---------------------
To show current stats::
$ ovs-appctl dpif-netdev/pmd-stats-show
To clear previous stats::
$ ovs-appctl dpif-netdev/pmd-stats-clear
Port/RXQ Assigment to PMD Threads
---------------------------------
To show port/rxq assignment::
$ ovs-appctl dpif-netdev/pmd-rxq-show
To change default rxq assignment to pmd threads, rxqs may be manually pinned to
desired cores using::
$ ovs-vsctl set Interface <iface> \
other_config:pmd-rxq-affinity=<rxq-affinity-list>
where:
- ``<rxq-affinity-list>`` is a CSV list of ``<queue-id>:<core-id>`` values
For example::
$ ovs-vsctl set interface dpdk-p0 options:n_rxq=4 \
other_config:pmd-rxq-affinity="0:3,1:7,3:8"
This will ensure:
- Queue #0 pinned to core 3
- Queue #1 pinned to core 7
- Queue #2 not pinned
- Queue #3 pinned to core 8
After that PMD threads on cores where RX queues was pinned will become
``isolated``. This means that this thread will poll only pinned RX queues.
.. warning::
If there are no ``non-isolated`` PMD threads, ``non-pinned`` RX queues will
not be polled. Also, if provided ``core_id`` is not available (ex. this
``core_id`` not in ``pmd-cpu-mask``), RX queue will not be polled by any PMD
thread.
If pmd-rxq-affinity is not set for rxqs, they will be assigned to pmds (cores)
automatically. The processing cycles that have been stored for each rxq
will be used where known to assign rxqs to pmd based on a round robin of the
sorted rxqs.
For example, in the case where here there are 5 rxqs and 3 cores (e.g. 3,7,8)
available, and the measured usage of core cycles per rxq over the last
interval is seen to be:
- Queue #0: 30%
- Queue #1: 80%
- Queue #3: 60%
- Queue #4: 70%
- Queue #5: 10%
The rxqs will be assigned to cores 3,7,8 in the following order:
Core 3: Q1 (80%) |
Core 7: Q4 (70%) | Q5 (10%)
core 8: Q3 (60%) | Q0 (30%)
To see the current measured usage history of pmd core cycles for each rxq::
$ ovs-appctl dpif-netdev/pmd-rxq-show
.. note::
A history of one minute is recorded and shown for each rxq to allow for
traffic pattern spikes. An rxq's pmd core cycles usage changes due to traffic
pattern or reconfig changes will take one minute before they are fully
reflected in the stats.
Rxq to pmds assignment takes place whenever there are configuration changes
or can be triggered by using::
$ ovs-appctl dpif-netdev/pmd-rxq-rebalance
QoS
---
Assuming you have a vhost-user port transmitting traffic consisting of packets
of size 64 bytes, the following command would limit the egress transmission
rate of the port to ~1,000,000 packets per second::
$ ovs-vsctl set port vhost-user0 qos=@newqos -- \
--id=@newqos create qos type=egress-policer other-config:cir=46000000 \
other-config:cbs=2048`
To examine the QoS configuration of the port, run::
$ ovs-appctl -t ovs-vswitchd qos/show vhost-user0
To clear the QoS configuration from the port and ovsdb, run::
$ ovs-vsctl destroy QoS vhost-user0 -- clear Port vhost-user0 qos
Refer to vswitch.xml for more details on egress-policer.
Rate Limiting
--------------
Here is an example on Ingress Policing usage. Assuming you have a vhost-user
port receiving traffic consisting of packets of size 64 bytes, the following
command would limit the reception rate of the port to ~1,000,000 packets per
second::
$ ovs-vsctl set interface vhost-user0 ingress_policing_rate=368000 \
ingress_policing_burst=1000`
To examine the ingress policer configuration of the port::
$ ovs-vsctl list interface vhost-user0
To clear the ingress policer configuration from the port::
$ ovs-vsctl set interface vhost-user0 ingress_policing_rate=0
Refer to vswitch.xml for more details on ingress-policer.
Flow Control
------------
Flow control can be enabled only on DPDK physical ports. To enable flow control
support at tx side while adding a port, run::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 options:tx-flow-ctrl=true
Similarly, to enable rx flow control, run::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 options:rx-flow-ctrl=true
To enable flow control auto-negotiation, run::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 options:flow-ctrl-autoneg=true
To turn ON the tx flow control at run time for an existing port, run::
$ ovs-vsctl set Interface dpdk-p0 options:tx-flow-ctrl=true
The flow control parameters can be turned off by setting ``false`` to the
respective parameter. To disable the flow control at tx side, run::
$ ovs-vsctl set Interface dpdk-p0 options:tx-flow-ctrl=false
pdump
-----
pdump allows you to listen on DPDK ports and view the traffic that is passing
on them. To use this utility, one must have libpcap installed on the system.
Furthermore, DPDK must be built with ``CONFIG_RTE_LIBRTE_PDUMP=y`` and
``CONFIG_RTE_LIBRTE_PMD_PCAP=y``.
.. warning::
A performance decrease is expected when using a monitoring application like
the DPDK pdump app.
To use pdump, simply launch OVS as usual, then navigate to the ``app/pdump``
directory in DPDK, ``make`` the application and run like so::
$ sudo ./build/app/dpdk-pdump -- \
--pdump port=0,queue=0,rx-dev=/tmp/pkts.pcap \
--server-socket-path=/usr/local/var/run/openvswitch
The above command captures traffic received on queue 0 of port 0 and stores it
in ``/tmp/pkts.pcap``. Other combinations of port numbers, queues numbers and
pcap locations are of course also available to use. For example, to capture all
packets that traverse port 0 in a single pcap file::
$ sudo ./build/app/dpdk-pdump -- \
--pdump 'port=0,queue=*,rx-dev=/tmp/pkts.pcap,tx-dev=/tmp/pkts.pcap' \
--server-socket-path=/usr/local/var/run/openvswitch
``server-socket-path`` must be set to the value of ``ovs_rundir()`` which
typically resolves to ``/usr/local/var/run/openvswitch``.
Many tools are available to view the contents of the pcap file. Once example is
tcpdump. Issue the following command to view the contents of ``pkts.pcap``::
$ tcpdump -r pkts.pcap
More information on the pdump app and its usage can be found in the `DPDK docs
<http://dpdk.org/doc/guides/tools/pdump.html>`__.
Jumbo Frames
------------
By default, DPDK ports are configured with standard Ethernet MTU (1500B). To
enable Jumbo Frames support for a DPDK port, change the Interface's
``mtu_request`` attribute to a sufficiently large value. For example, to add a
DPDK Phy port with MTU of 9000::
$ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 mtu_request=9000
Similarly, to change the MTU of an existing port to 6200::
$ ovs-vsctl set Interface dpdk-p0 mtu_request=6200
Some additional configuration is needed to take advantage of jumbo frames with
vHost ports:
1. *mergeable buffers* must be enabled for vHost ports, as demonstrated in the
QEMU command line snippet below::
-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \
-device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=on
2. Where virtio devices are bound to the Linux kernel driver in a guest
environment (i.e. interfaces are not bound to an in-guest DPDK driver), the
MTU of those logical network interfaces must also be increased to a
sufficiently large value. This avoids segmentation of Jumbo Frames received
in the guest. Note that 'MTU' refers to the length of the IP packet only,
and not that of the entire frame.
To calculate the exact MTU of a standard IPv4 frame, subtract the L2 header
and CRC lengths (i.e. 18B) from the max supported frame size. So, to set
the MTU for a 9018B Jumbo Frame::
$ ip link set eth1 mtu 9000
When Jumbo Frames are enabled, the size of a DPDK port's mbuf segments are
increased, such that a full Jumbo Frame of a specific size may be accommodated
within a single mbuf segment.
Jumbo frame support has been validated against 9728B frames, which is the
largest frame size supported by Fortville NIC using the DPDK i40e driver, but
larger frames and other DPDK NIC drivers may be supported. These cases are
common for use cases involving East-West traffic only.
Rx Checksum Offload
-------------------
By default, DPDK physical ports are enabled with Rx checksum offload.
Rx checksum offload can offer performance improvement only for tunneling
traffic in OVS-DPDK because the checksum validation of tunnel packets is
offloaded to the NIC. Also enabling Rx checksum may slightly reduce the
performance of non-tunnel traffic, specifically for smaller size packet.
.. _extended-statistics:
Extended & Custom Statistics
----------------------------
DPDK Extended Statistics API allows PMD to expose unique set of statistics.
The Extended statistics are implemented and supported only for DPDK physical
and vHost ports. Custom statistics are dynamic set of counters which can
vary depenend on a driver. Those statistics are implemented
for DPDK physical ports and contain all "dropped", "error" and "management"
counters from XSTATS. XSTATS counters list can be found here:
<https://wiki.opnfv.org/display/fastpath/Collectd+Metrics+and+Events>`__.
To enable statistics, you have to enable OpenFlow 1.4 support for OVS.
Configure bridge br0 to support OpenFlow version 1.4::
$ ovs-vsctl set bridge br0 datapath_type=netdev \
protocols=OpenFlow10,OpenFlow11,OpenFlow12,OpenFlow13,OpenFlow14
Check the OVSDB protocols column in the bridge table if OpenFlow 1.4 support
is enabled for OVS::
$ ovsdb-client dump Bridge protocols
Query the port statistics by explicitly specifying -O OpenFlow14 option::
$ ovs-ofctl -O OpenFlow14 dump-ports br0
Note about "Extended Statistics": vHost ports supports only partial
statistics. RX packet size based counter are only supported and
doesn't include TX packet size counters.
.. _port-hotplug:
Port Hotplug
------------
OVS supports port hotplugging, allowing the use of ports that were not bound
to DPDK when vswitchd was started.
In order to attach a port, it has to be bound to DPDK using the
``dpdk_nic_bind.py`` script::
$ $DPDK_DIR/tools/dpdk_nic_bind.py --bind=igb_uio 0000:01:00.0
Then it can be attached to OVS::
$ ovs-vsctl add-port br0 dpdkx -- set Interface dpdkx type=dpdk \
options:dpdk-devargs=0000:01:00.0
Detaching will be performed while processing del-port command::
$ ovs-vsctl del-port dpdkx
Sometimes, the del-port command may not detach the device.
Detaching can be confirmed by the appearance of an INFO log.
For example::
INFO|Device '0000:04:00.1' has been detached
If the log is not seen, then the port can be detached using::
$ ovs-appctl netdev-dpdk/detach 0000:01:00.0
Detaching can be confirmed by console output::
Device '0000:04:00.1' has been detached
.. warning::
Detaching should not be done if a device is known to be non-detachable, as
this may cause the device to behave improperly when added back with
add-port. The Chelsio Terminator adapters which use the cxgbe driver seem
to be an example of this behavior; check the driver documentation if this
is suspected.
This feature does not work with some NICs.
For more information please refer to the `DPDK Port Hotplug Framework
<http://dpdk.org/doc/guides/prog_guide/port_hotplug_framework.html#hotplug>`__.
.. _vdev-support:
Vdev Support
------------
DPDK provides drivers for both physical and virtual devices. Physical DPDK
devices are added to OVS by specifying a valid PCI address in 'dpdk-devargs'.
Virtual DPDK devices which do not have PCI addresses can be added using a
different format for 'dpdk-devargs'.
Typically, the format expected is 'eth_<driver_name><x>' where 'x' is a
unique identifier of your choice for the given port.
For example to add a dpdk port that uses the 'null' DPDK PMD driver::
$ ovs-vsctl add-port br0 null0 -- set Interface null0 type=dpdk \
options:dpdk-devargs=eth_null0
Similarly, to add a dpdk port that uses the 'af_packet' DPDK PMD driver::
$ ovs-vsctl add-port br0 myeth0 -- set Interface myeth0 type=dpdk \
options:dpdk-devargs=eth_af_packet0,iface=eth0
More information on the different types of virtual DPDK PMDs can be found in
the `DPDK documentation
<http://dpdk.org/doc/guides/nics/overview.html>`__.
Note: Not all DPDK virtual PMD drivers have been tested and verified to work.
EMC Insertion Probability
-------------------------
By default 1 in every 100 flows are inserted into the Exact Match Cache (EMC).
It is possible to change this insertion probability by setting the
``emc-insert-inv-prob`` option::
$ ovs-vsctl --no-wait set Open_vSwitch . other_config:emc-insert-inv-prob=N
where:
``N``
is a positive integer representing the inverse probability of insertion ie.
on average 1 in every N packets with a unique flow will generate an EMC
insertion.
If ``N`` is set to 1, an insertion will be performed for every flow. If set to
0, no insertions will be performed and the EMC will effectively be disabled.
With default ``N`` set to 100, higher megaflow hits will occur initially
as observed with pmd stats::
$ ovs-appctl dpif-netdev/pmd-stats-show
For certain traffic profiles with many parallel flows, it's recommended to set
``N`` to '0' to achieve higher forwarding performance.
For more information on the EMC refer to :doc:`/intro/install/dpdk` .
.. _dpdk-ovs-in-guest:
OVS with DPDK Inside VMs
------------------------
Additional configuration is required if you want to run ovs-vswitchd with DPDK
backend inside a QEMU virtual machine. ovs-vswitchd creates separate DPDK TX
queues for each CPU core available. This operation fails inside QEMU virtual
machine because, by default, VirtIO NIC provided to the guest is configured to
support only single TX queue and single RX queue. To change this behavior, you
need to turn on ``mq`` (multiqueue) property of all ``virtio-net-pci`` devices
emulated by QEMU and used by DPDK. You may do it manually (by changing QEMU
command line) or, if you use Libvirt, by adding the following string to
``<interface>`` sections of all network devices used by DPDK::
<driver name='vhost' queues='N'/>
where:
``N``
determines how many queues can be used by the guest.
This requires QEMU >= 2.2.
.. _dpdk-phy-phy:
PHY-PHY
-------
Add a userspace bridge and two ``dpdk`` (PHY) ports::
# Add userspace bridge
$ ovs-vsctl add-br br0 -- set bridge br0 datapath_type=netdev
# Add two dpdk ports
$ ovs-vsctl add-port br0 phy0 -- set Interface phy0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 ofport_request=1
$ ovs-vsctl add-port br0 phy1 -- set Interface phy1 type=dpdk
options:dpdk-devargs=0000:01:00.1 ofport_request=2
Add test flows to forward packets betwen DPDK port 0 and port 1::
# Clear current flows
$ ovs-ofctl del-flows br0
# Add flows between port 1 (phy0) to port 2 (phy1)
$ ovs-ofctl add-flow br0 in_port=1,action=output:2
$ ovs-ofctl add-flow br0 in_port=2,action=output:1
Transmit traffic into either port. You should see it returned via the other.
.. _dpdk-vhost-loopback:
PHY-VM-PHY (vHost Loopback)
---------------------------
Add a userspace bridge, two ``dpdk`` (PHY) ports, and two ``dpdkvhostuser``
ports::
# Add userspace bridge
$ ovs-vsctl add-br br0 -- set bridge br0 datapath_type=netdev
# Add two dpdk ports
$ ovs-vsctl add-port br0 phy0 -- set Interface phy0 type=dpdk \
options:dpdk-devargs=0000:01:00.0 ofport_request=1
$ ovs-vsctl add-port br0 phy1 -- set Interface phy1 type=dpdk
options:dpdk-devargs=0000:01:00.1 ofport_request=2
# Add two dpdkvhostuser ports
$ ovs-vsctl add-port br0 dpdkvhostuser0 \
-- set Interface dpdkvhostuser0 type=dpdkvhostuser ofport_request=3
$ ovs-vsctl add-port br0 dpdkvhostuser1 \
-- set Interface dpdkvhostuser1 type=dpdkvhostuser ofport_request=4
Add test flows to forward packets betwen DPDK devices and VM ports::
# Clear current flows
$ ovs-ofctl del-flows br0
# Add flows
$ ovs-ofctl add-flow br0 in_port=1,action=output:3
$ ovs-ofctl add-flow br0 in_port=3,action=output:1
$ ovs-ofctl add-flow br0 in_port=4,action=output:2
$ ovs-ofctl add-flow br0 in_port=2,action=output:4
# Dump flows
$ ovs-ofctl dump-flows br0
Create a VM using the following configuration:
.. table::
===================== ======== ============
Configuration Values Comments
===================== ======== ============
QEMU version 2.2.0 n/a
QEMU thread affinity core 5 taskset 0x20
Memory 4GB n/a
Cores 2 n/a
Qcow2 image CentOS7 n/a
mrg_rxbuf off n/a
===================== ======== ============
You can do this directly with QEMU via the ``qemu-system-x86_64`` application::
$ export VM_NAME=vhost-vm
$ export GUEST_MEM=3072M
$ export QCOW2_IMAGE=/root/CentOS7_x86_64.qcow2
$ export VHOST_SOCK_DIR=/usr/local/var/run/openvswitch
$ taskset 0x20 qemu-system-x86_64 -name $VM_NAME -cpu host -enable-kvm \
-m $GUEST_MEM -drive file=$QCOW2_IMAGE --nographic -snapshot \
-numa node,memdev=mem -mem-prealloc -smp sockets=1,cores=2 \
-object memory-backend-file,id=mem,size=$GUEST_MEM,mem-path=/dev/hugepages,share=on \
-chardev socket,id=char0,path=$VHOST_SOCK_DIR/dpdkvhostuser0 \
-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \
-device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mrg_rxbuf=off \
-chardev socket,id=char1,path=$VHOST_SOCK_DIR/dpdkvhostuser1 \
-netdev type=vhost-user,id=mynet2,chardev=char1,vhostforce \
-device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2,mrg_rxbuf=off
For a explanation of this command, along with alternative approaches such as
booting the VM via libvirt, refer to :doc:`/topics/dpdk/vhost-user`.
Once the guest is configured and booted, configure DPDK packet forwarding
within the guest. To accomplish this, build the ``testpmd`` application as
described in :ref:`dpdk-testpmd`. Once compiled, run the application::
$ cd $DPDK_DIR/app/test-pmd;
$ ./testpmd -c 0x3 -n 4 --socket-mem 1024 -- \
--burst=64 -i --txqflags=0xf00 --disable-hw-vlan
$ set fwd mac retry
$ start
When you finish testing, bind the vNICs back to kernel::
$ $DPDK_DIR/usertools/dpdk-devbind.py --bind=virtio-pci 0000:00:03.0
$ $DPDK_DIR/usertools/dpdk-devbind.py --bind=virtio-pci 0000:00:04.0
.. note::
Valid PCI IDs must be passed in above example. The PCI IDs can be retrieved
like so::
$ $DPDK_DIR/usertools/dpdk-devbind.py --status
More information on the dpdkvhostuser ports can be found in
:doc:`/topics/dpdk/vhost-user`.
PHY-VM-PHY (vHost Loopback) (Kernel Forwarding)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:ref:`dpdk-vhost-loopback` details steps for PHY-VM-PHY loopback
testcase and packet forwarding using DPDK testpmd application in the Guest VM.
For users wishing to do packet forwarding using kernel stack below, you need to
run the below commands on the guest::
$ ip addr add 1.1.1.2/24 dev eth1
$ ip addr add 1.1.2.2/24 dev eth2
$ ip link set eth1 up
$ ip link set eth2 up
$ systemctl stop firewalld.service
$ systemctl stop iptables.service
$ sysctl -w net.ipv4.ip_forward=1
$ sysctl -w net.ipv4.conf.all.rp_filter=0
$ sysctl -w net.ipv4.conf.eth1.rp_filter=0
$ sysctl -w net.ipv4.conf.eth2.rp_filter=0
$ route add -net 1.1.2.0/24 eth2
$ route add -net 1.1.1.0/24 eth1
$ arp -s 1.1.2.99 DE:AD:BE:EF:CA:FE
$ arp -s 1.1.1.99 DE:AD:BE:EF:CA:EE
PHY-VM-PHY (vHost Multiqueue)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vHost Multiqueue functionality can also be validated using the PHY-VM-PHY
configuration. To begin, follow the steps described in :ref:`dpdk-phy-phy` to
create and initialize the database, start ovs-vswitchd and add ``dpdk``-type
devices to bridge ``br0``. Once complete, follow the below steps:
1. Configure PMD and RXQs.
For example, set the number of dpdk port rx queues to at least 2 The number
of rx queues at vhost-user interface gets automatically configured after
virtio device connection and doesn't need manual configuration::
$ ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=0xc
$ ovs-vsctl set Interface phy0 options:n_rxq=2
$ ovs-vsctl set Interface phy1 options:n_rxq=2
2. Instantiate Guest VM using QEMU cmdline
We must configure with appropriate software versions to ensure this feature
is supported.
.. list-table:: Recommended BIOS Settings
:header-rows: 1
* - Setting
- Value
* - QEMU version
- 2.5.0
* - QEMU thread affinity
- 2 cores (taskset 0x30)
* - Memory
- 4 GB
* - Cores
- 2
* - Distro
- Fedora 22
* - Multiqueue
- Enabled
To do this, instantiate the guest as follows::
$ export VM_NAME=vhost-vm
$ export GUEST_MEM=4096M
$ export QCOW2_IMAGE=/root/Fedora22_x86_64.qcow2
$ export VHOST_SOCK_DIR=/usr/local/var/run/openvswitch
$ taskset 0x30 qemu-system-x86_64 -cpu host -smp 2,cores=2 -m 4096M \
-drive file=$QCOW2_IMAGE --enable-kvm -name $VM_NAME \
-nographic -numa node,memdev=mem -mem-prealloc \
-object memory-backend-file,id=mem,size=$GUEST_MEM,mem-path=/dev/hugepages,share=on \
-chardev socket,id=char1,path=$VHOST_SOCK_DIR/dpdkvhostuser0 \
-netdev type=vhost-user,id=mynet1,chardev=char1,vhostforce,queues=2 \
-device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1,mq=on,vectors=6 \
-chardev socket,id=char2,path=$VHOST_SOCK_DIR/dpdkvhostuser1 \
-netdev type=vhost-user,id=mynet2,chardev=char2,vhostforce,queues=2 \
-device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2,mq=on,vectors=6
.. note::
Queue value above should match the queues configured in OVS, The vector
value should be set to "number of queues x 2 + 2"
3. Configure the guest interface
Assuming there are 2 interfaces in the guest named eth0, eth1 check the
channel configuration and set the number of combined channels to 2 for
virtio devices::
$ ethtool -l eth0
$ ethtool -L eth0 combined 2
$ ethtool -L eth1 combined 2
More information can be found in vHost walkthrough section.
4. Configure kernel packet forwarding
Configure IP and enable interfaces::
$ ip addr add 5.5.5.1/24 dev eth0
$ ip addr add 90.90.90.1/24 dev eth1
$ ip link set eth0 up
$ ip link set eth1 up
Configure IP forwarding and add route entries::
$ sysctl -w net.ipv4.ip_forward=1
$ sysctl -w net.ipv4.conf.all.rp_filter=0
$ sysctl -w net.ipv4.conf.eth0.rp_filter=0
$ sysctl -w net.ipv4.conf.eth1.rp_filter=0
$ ip route add 2.1.1.0/24 dev eth1
$ route add default gw 2.1.1.2 eth1
$ route add default gw 90.90.90.90 eth1
$ arp -s 90.90.90.90 DE:AD:BE:EF:CA:FE
$ arp -s 2.1.1.2 DE:AD:BE:EF:CA:FA
Check traffic on multiple queues::
$ cat /proc/interrupts | grep virtio
|