Building and Installing:
------------------------
-Required: DPDK 2.2
+Required: DPDK 16.04, libnuma
Optional (if building with vhost-cuse): `fuse`, `fuse-devel` (`libfuse-dev`
on Debian/Ubuntu)
1. Set `$DPDK_DIR`
```
- export DPDK_DIR=/usr/src/dpdk-2.2
+ export DPDK_DIR=/usr/src/dpdk-16.04
cd $DPDK_DIR
```
- 2. Update `config/common_linuxapp` so that DPDK generate single lib file.
- (modification also required for IVSHMEM build)
-
- `CONFIG_RTE_BUILD_COMBINE_LIBS=y`
-
- Then run `make install` to build and install the library.
+ 2. Then run `make install` to build and install the library.
For default install without IVSHMEM:
- `make install T=x86_64-native-linuxapp-gcc`
+ `make install T=x86_64-native-linuxapp-gcc DESTDIR=install`
To include IVSHMEM (shared memory):
- `make install T=x86_64-ivshmem-linuxapp-gcc`
+ `make install T=x86_64-ivshmem-linuxapp-gcc DESTDIR=install`
For further details refer to http://dpdk.org/
5. Start vswitchd:
- DPDK configuration arguments can be passed to vswitchd via `--dpdk`
- argument. This needs to be first argument passed to vswitchd process.
- dpdk arg -c is ignored by ovs-dpdk, but it is a required parameter
- for dpdk initialization.
+ DPDK configuration arguments can be passed to vswitchd via Open_vSwitch
+ other_config column. The recognized configuration options are listed.
+ Defaults will be provided for all values not explicitly set.
+
+ * dpdk-init
+ Specifies whether OVS should initialize and support DPDK ports. This is
+ a boolean, and defaults to false.
+
+ * dpdk-lcore-mask
+ Specifies the CPU cores on which dpdk lcore threads should be spawned.
+ The DPDK lcore threads are used for DPDK library tasks, such as
+ library internal message processing, logging, etc. Value should be in
+ the form of a hex string (so '0x123') similar to the 'taskset' mask
+ input.
+ If not specified, the value will be determined by choosing the lowest
+ CPU core from initial cpu affinity list. Otherwise, the value will be
+ passed directly to the DPDK library.
+ For performance reasons, it is best to set this to a single core on
+ the system, rather than allow lcore threads to float.
+
+ * dpdk-alloc-mem
+ This sets the total memory to preallocate from hugepages regardless of
+ processor socket. It is recommended to use dpdk-socket-mem instead.
+
+ * dpdk-socket-mem
+ Comma separated list of memory to pre-allocate from hugepages on specific
+ sockets.
+
+ * dpdk-hugepage-dir
+ Directory where hugetlbfs is mounted
+
+ * dpdk-extra
+ Extra arguments to provide to DPDK EAL, as previously specified on the
+ command line. Do not pass '--no-huge' to the system in this way. Support
+ for running the system without hugepages is nonexistent.
+
+ * cuse-dev-name
+ Option to set the vhost_cuse character device name.
+
+ * vhost-sock-dir
+ Option to set the path to the vhost_user unix socket files.
+
+ NOTE: Changing any of these options requires restarting the ovs-vswitchd
+ application.
+
+ Open vSwitch can be started as normal. DPDK will be initialized as long
+ as the dpdk-init option has been set to 'true'.
+
```
export DB_SOCK=/usr/local/var/run/openvswitch/db.sock
- ovs-vswitchd --dpdk -c 0x1 -n 4 -- unix:$DB_SOCK --pidfile --detach
+ ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=true
+ ovs-vswitchd unix:$DB_SOCK --pidfile --detach
```
If allocated more than one GB hugepage (as for IVSHMEM), set amount and
use NUMA node 0 memory:
```
- ovs-vswitchd --dpdk -c 0x1 -n 4 --socket-mem 1024,0 \
- -- unix:$DB_SOCK --pidfile --detach
+ ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-socket-mem="1024,0"
+ ovs-vswitchd unix:$DB_SOCK --pidfile --detach
```
6. Add bridge & ports
./ovs-ofctl add-flow br0 in_port=2,action=output:1
```
-Performance Tuning:
--------------------
+8. QoS usage example
- 1. PMD affinitization
+ 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:
- A poll mode driver (pmd) thread handles the I/O of all DPDK
- interfaces assigned to it. A pmd thread will busy loop through
- the assigned port/rxq's polling for packets, switch the packets
- and send to a tx port if required. Typically, it is found that
- a pmd thread is CPU bound, meaning that the greater the CPU
- occupancy the pmd thread can get, the better the performance. To
- that end, it is good practice to ensure that a pmd thread has as
- many cycles on a core available to it as possible. This can be
- achieved by affinitizing the pmd thread with a core that has no
- other workload. See section 7 below for a description of how to
- isolate cores for this purpose also.
+ `ovs-vsctl set port vhost-user0 qos=@newqos -- --id=@newqos create qos
+ type=egress-policer other-config:cir=46000000 other-config:cbs=2048`
- The following command can be used to specify the affinity of the
- pmd thread(s).
+ To examine the QoS configuration of the port:
- `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=<hex string>`
+ `ovs-appctl -t ovs-vswitchd qos/show vhost-user0`
- By setting a bit in the mask, a pmd thread is created and pinned
- to the corresponding CPU core. e.g. to run a pmd thread on core 1
+ To clear the QoS configuration from the port and ovsdb use the following:
- `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=2`
+ `ovs-vsctl destroy QoS vhost-user0 -- clear Port vhost-user0 qos`
- For more information, please refer to the Open_vSwitch TABLE section in
+ For more details regarding egress-policer parameters please refer to the
+ vswitch.xml.
- `man ovs-vswitchd.conf.db`
+9. Ingress Policing Example
- Note, that a pmd thread on a NUMA node is only created if there is
- at least one DPDK interface from that NUMA node added to OVS.
+ 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:
- 2. Multiple poll mode driver threads
+ `ovs-vsctl set interface vhost-user0 ingress_policing_rate=368000
+ ingress_policing_burst=1000`
- With pmd multi-threading support, OVS creates one pmd thread
- for each NUMA node by default. However, it can be seen that in cases
- where there are multiple ports/rxq's producing traffic, performance
- can be improved by creating multiple pmd threads running on separate
- cores. These pmd threads can then share the workload by each being
- responsible for different ports/rxq's. Assignment of ports/rxq's to
- pmd threads is done automatically.
+ To examine the ingress policer configuration of the port:
- The following command can be used to specify the affinity of the
- pmd threads.
+ `ovs-vsctl list interface vhost-user0`
- `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=<hex string>`
+ To clear the ingress policer configuration from the port use the following:
- A set bit in the mask means a pmd thread is created and pinned
- to the corresponding CPU core. e.g. to run pmd threads on core 1 and 2
+ `ovs-vsctl set interface vhost-user0 ingress_policing_rate=0`
- `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=6`
+ For more details regarding ingress-policer see the vswitch.xml.
- For more information, please refer to the Open_vSwitch TABLE section in
+Performance Tuning:
+-------------------
- `man ovs-vswitchd.conf.db`
+1. PMD affinitization
- For example, when using dpdk and dpdkvhostuser ports in a bi-directional
- VM loopback as shown below, spreading the workload over 2 or 4 pmd
- threads shows significant improvements as there will be more total CPU
- occupancy available.
+ A poll mode driver (pmd) thread handles the I/O of all DPDK
+ interfaces assigned to it. A pmd thread will busy loop through
+ the assigned port/rxq's polling for packets, switch the packets
+ and send to a tx port if required. Typically, it is found that
+ a pmd thread is CPU bound, meaning that the greater the CPU
+ occupancy the pmd thread can get, the better the performance. To
+ that end, it is good practice to ensure that a pmd thread has as
+ many cycles on a core available to it as possible. This can be
+ achieved by affinitizing the pmd thread with a core that has no
+ other workload. See section 7 below for a description of how to
+ isolate cores for this purpose also.
- NIC port0 <-> OVS <-> VM <-> OVS <-> NIC port 1
+ The following command can be used to specify the affinity of the
+ pmd thread(s).
- The following command can be used to confirm that the port/rxq assignment
- to pmd threads is as required:
+ `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=<hex string>`
- `ovs-appctl dpif-netdev/pmd-rxq-show`
+ By setting a bit in the mask, a pmd thread is created and pinned
+ to the corresponding CPU core. e.g. to run a pmd thread on core 1
- This can also be checked with:
+ `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=2`
- ```
- top -H
- taskset -p <pid_of_pmd>
- ```
+ For more information, please refer to the Open_vSwitch TABLE section in
- To understand where most of the pmd thread time is spent and whether the
- caches are being utilized, these commands can be used:
+ `man ovs-vswitchd.conf.db`
- ```
- # Clear previous stats
- ovs-appctl dpif-netdev/pmd-stats-clear
+ Note, that a pmd thread on a NUMA node is only created if there is
+ at least one DPDK interface from that NUMA node added to OVS.
- # Check current stats
- ovs-appctl dpif-netdev/pmd-stats-show
- ```
+2. Multiple poll mode driver threads
- 3. DPDK port Rx Queues
+ With pmd multi-threading support, OVS creates one pmd thread
+ for each NUMA node by default. However, it can be seen that in cases
+ where there are multiple ports/rxq's producing traffic, performance
+ can be improved by creating multiple pmd threads running on separate
+ cores. These pmd threads can then share the workload by each being
+ responsible for different ports/rxq's. Assignment of ports/rxq's to
+ pmd threads is done automatically.
- `ovs-vsctl set Interface <DPDK interface> options:n_rxq=<integer>`
+ The following command can be used to specify the affinity of the
+ pmd threads.
- The command above sets the number of rx queues for DPDK interface.
- The rx queues are assigned to pmd threads on the same NUMA node in a
- round-robin fashion. For more information, please refer to the
- Open_vSwitch TABLE section in
+ `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=<hex string>`
- `man ovs-vswitchd.conf.db`
+ A set bit in the mask means a pmd thread is created and pinned
+ to the corresponding CPU core. e.g. to run pmd threads on core 1 and 2
- 4. Exact Match Cache
+ `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=6`
- Each pmd thread contains one EMC. After initial flow setup in the
- datapath, the EMC contains a single table and provides the lowest level
- (fastest) switching for DPDK ports. If there is a miss in the EMC then
- the next level where switching will occur is the datapath classifier.
- Missing in the EMC and looking up in the datapath classifier incurs a
- significant performance penalty. If lookup misses occur in the EMC
- because it is too small to handle the number of flows, its size can
- be increased. The EMC size can be modified by editing the define
- EM_FLOW_HASH_SHIFT in lib/dpif-netdev.c.
+ For more information, please refer to the Open_vSwitch TABLE section in
- As mentioned above an EMC is per pmd thread. So an alternative way of
- increasing the aggregate amount of possible flow entries in EMC and
- avoiding datapath classifier lookups is to have multiple pmd threads
- running. This can be done as described in section 2.
+ `man ovs-vswitchd.conf.db`
- 5. Compiler options
+ For example, when using dpdk and dpdkvhostuser ports in a bi-directional
+ VM loopback as shown below, spreading the workload over 2 or 4 pmd
+ threads shows significant improvements as there will be more total CPU
+ occupancy available.
- The default compiler optimization level is '-O2'. Changing this to
- more aggressive compiler optimizations such as '-O3' or
- '-Ofast -march=native' with gcc can produce performance gains.
+ NIC port0 <-> OVS <-> VM <-> OVS <-> NIC port 1
- 6. Simultaneous Multithreading (SMT)
+ The following command can be used to confirm that the port/rxq assignment
+ to pmd threads is as required:
- With SMT enabled, one physical core appears as two logical cores
- which can improve performance.
+ `ovs-appctl dpif-netdev/pmd-rxq-show`
- SMT can be utilized to add additional pmd threads without consuming
- additional physical cores. Additional pmd threads may be added in the
- same manner as described in section 2. If trying to minimize the use
- of physical cores for pmd threads, care must be taken to set the
- correct bits in the pmd-cpu-mask to ensure that the pmd threads are
- pinned to SMT siblings.
+ This can also be checked with:
- For example, when using 2x 10 core processors in a dual socket system
- with HT enabled, /proc/cpuinfo will report 40 logical cores. To use
- two logical cores which share the same physical core for pmd threads,
- the following command can be used to identify a pair of logical cores.
+ ```
+ top -H
+ taskset -p <pid_of_pmd>
+ ```
- `cat /sys/devices/system/cpu/cpuN/topology/thread_siblings_list`
+ To understand where most of the pmd thread time is spent and whether the
+ caches are being utilized, these commands can be used:
- where N is the logical core number. In this example, it would show that
- cores 1 and 21 share the same physical core. The pmd-cpu-mask to enable
- two pmd threads running on these two logical cores (one physical core)
- is.
+ ```
+ # Clear previous stats
+ ovs-appctl dpif-netdev/pmd-stats-clear
+
+ # Check current stats
+ ovs-appctl dpif-netdev/pmd-stats-show
+ ```
- `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=100002`
+3. DPDK port Rx Queues
- Note that SMT is enabled by the Hyper-Threading section in the
- BIOS, and as such will apply to the whole system. So the impact of
- enabling/disabling it for the whole system should be considered
- e.g. If workloads on the system can scale across multiple cores,
- SMT may very beneficial. However, if they do not and perform best
- on a single physical core, SMT may not be beneficial.
+ `ovs-vsctl set Interface <DPDK interface> options:n_rxq=<integer>`
- 7. The isolcpus kernel boot parameter
+ The command above sets the number of rx queues for DPDK interface.
+ The rx queues are assigned to pmd threads on the same NUMA node in a
+ round-robin fashion. For more information, please refer to the
+ Open_vSwitch TABLE section in
- isolcpus can be used on the kernel bootline to isolate cores from the
- kernel scheduler and hence dedicate them to OVS or other packet
- forwarding related workloads. For example a Linux kernel boot-line
- could be:
+ `man ovs-vswitchd.conf.db`
- 'GRUB_CMDLINE_LINUX_DEFAULT="quiet hugepagesz=1G hugepages=4 default_hugepagesz=1G 'intel_iommu=off' isolcpus=1-19"'
+4. Exact Match Cache
- 8. NUMA/Cluster On Die
+ Each pmd thread contains one EMC. After initial flow setup in the
+ datapath, the EMC contains a single table and provides the lowest level
+ (fastest) switching for DPDK ports. If there is a miss in the EMC then
+ the next level where switching will occur is the datapath classifier.
+ Missing in the EMC and looking up in the datapath classifier incurs a
+ significant performance penalty. If lookup misses occur in the EMC
+ because it is too small to handle the number of flows, its size can
+ be increased. The EMC size can be modified by editing the define
+ EM_FLOW_HASH_SHIFT in lib/dpif-netdev.c.
- Ideally inter NUMA datapaths should be avoided where possible as packets
- will go across QPI and there may be a slight performance penalty when
- compared with intra NUMA datapaths. On Intel Xeon Processor E5 v3,
- Cluster On Die is introduced on models that have 10 cores or more.
- This makes it possible to logically split a socket into two NUMA regions
- and again it is preferred where possible to keep critical datapaths
- within the one cluster.
+ As mentioned above an EMC is per pmd thread. So an alternative way of
+ increasing the aggregate amount of possible flow entries in EMC and
+ avoiding datapath classifier lookups is to have multiple pmd threads
+ running. This can be done as described in section 2.
- It is good practice to ensure that threads that are in the datapath are
- pinned to cores in the same NUMA area. e.g. pmd threads and QEMU vCPUs
- responsible for forwarding.
+5. Compiler options
- 9. Rx Mergeable buffers
+ The default compiler optimization level is '-O2'. Changing this to
+ more aggressive compiler optimizations such as '-O3' or
+ '-Ofast -march=native' with gcc can produce performance gains.
- Rx Mergeable buffers is a virtio feature that allows chaining of multiple
- virtio descriptors to handle large packet sizes. As such, large packets
- are handled by reserving and chaining multiple free descriptors
- together. Mergeable buffer support is negotiated between the virtio
- driver and virtio device and is supported by the DPDK vhost library.
- This behavior is typically supported and enabled by default, however
- in the case where the user knows that rx mergeable buffers are not needed
- i.e. jumbo frames are not needed, it can be forced off by adding
- mrg_rxbuf=off to the QEMU command line options. By not reserving multiple
- chains of descriptors it will make more individual virtio descriptors
- available for rx to the guest using dpdkvhost ports and this can improve
- performance.
-
- 10. Packet processing in the guest
+6. Simultaneous Multithreading (SMT)
- It is good practice whether simply forwarding packets from one
- interface to another or more complex packet processing in the guest,
- to ensure that the thread performing this work has as much CPU
- occupancy as possible. For example when the DPDK sample application
- `testpmd` is used to forward packets in the guest, multiple QEMU vCPU
- threads can be created. Taskset can then be used to affinitize the
- vCPU thread responsible for forwarding to a dedicated core not used
- for other general processing on the host system.
-
- 11. DPDK virtio pmd in the guest
-
- dpdkvhostcuse or dpdkvhostuser ports can be used to accelerate the path
- to the guest using the DPDK vhost library. This library is compatible with
- virtio-net drivers in the guest but significantly better performance can
- be observed when using the DPDK virtio pmd driver in the guest. The DPDK
- `testpmd` application can be used in the guest as an example application
- that forwards packet from one DPDK vhost port to another. An example of
- running `testpmd` in the guest can be seen here.
+ With SMT enabled, one physical core appears as two logical cores
+ which can improve performance.
- `./testpmd -c 0x3 -n 4 --socket-mem 512 -- --burst=64 -i --txqflags=0xf00 --disable-hw-vlan --forward-mode=io --auto-start`
+ SMT can be utilized to add additional pmd threads without consuming
+ additional physical cores. Additional pmd threads may be added in the
+ same manner as described in section 2. If trying to minimize the use
+ of physical cores for pmd threads, care must be taken to set the
+ correct bits in the pmd-cpu-mask to ensure that the pmd threads are
+ pinned to SMT siblings.
- See below information on dpdkvhostcuse and dpdkvhostuser ports.
- See [DPDK Docs] for more information on `testpmd`.
+ For example, when using 2x 10 core processors in a dual socket system
+ with HT enabled, /proc/cpuinfo will report 40 logical cores. To use
+ two logical cores which share the same physical core for pmd threads,
+ the following command can be used to identify a pair of logical cores.
+ `cat /sys/devices/system/cpu/cpuN/topology/thread_siblings_list`
+ where N is the logical core number. In this example, it would show that
+ cores 1 and 21 share the same physical core. The pmd-cpu-mask to enable
+ two pmd threads running on these two logical cores (one physical core)
+ is.
+
+ `ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=100002`
+
+ Note that SMT is enabled by the Hyper-Threading section in the
+ BIOS, and as such will apply to the whole system. So the impact of
+ enabling/disabling it for the whole system should be considered
+ e.g. If workloads on the system can scale across multiple cores,
+ SMT may very beneficial. However, if they do not and perform best
+ on a single physical core, SMT may not be beneficial.
+
+7. The isolcpus kernel boot parameter
+
+ isolcpus can be used on the kernel bootline to isolate cores from the
+ kernel scheduler and hence dedicate them to OVS or other packet
+ forwarding related workloads. For example a Linux kernel boot-line
+ could be:
+
+ ```
+ GRUB_CMDLINE_LINUX_DEFAULT="quiet hugepagesz=1G hugepages=4
+ default_hugepagesz=1G 'intel_iommu=off' isolcpus=1-19"
+ ```
+
+8. NUMA/Cluster On Die
+
+ Ideally inter NUMA datapaths should be avoided where possible as packets
+ will go across QPI and there may be a slight performance penalty when
+ compared with intra NUMA datapaths. On Intel Xeon Processor E5 v3,
+ Cluster On Die is introduced on models that have 10 cores or more.
+ This makes it possible to logically split a socket into two NUMA regions
+ and again it is preferred where possible to keep critical datapaths
+ within the one cluster.
+
+ It is good practice to ensure that threads that are in the datapath are
+ pinned to cores in the same NUMA area. e.g. pmd threads and QEMU vCPUs
+ responsible for forwarding. If DPDK is built with
+ CONFIG_RTE_LIBRTE_VHOST_NUMA=y, vHost User ports automatically
+ detect the NUMA socket of the QEMU vCPUs and will be serviced by a PMD
+ from the same node provided a core on this node is enabled in the
+ pmd-cpu-mask.
+
+9. Rx Mergeable buffers
+
+ Rx Mergeable buffers is a virtio feature that allows chaining of multiple
+ virtio descriptors to handle large packet sizes. As such, large packets
+ are handled by reserving and chaining multiple free descriptors
+ together. Mergeable buffer support is negotiated between the virtio
+ driver and virtio device and is supported by the DPDK vhost library.
+ This behavior is typically supported and enabled by default, however
+ in the case where the user knows that rx mergeable buffers are not needed
+ i.e. jumbo frames are not needed, it can be forced off by adding
+ mrg_rxbuf=off to the QEMU command line options. By not reserving multiple
+ chains of descriptors it will make more individual virtio descriptors
+ available for rx to the guest using dpdkvhost ports and this can improve
+ performance.
+
+10. Packet processing in the guest
+
+ It is good practice whether simply forwarding packets from one
+ interface to another or more complex packet processing in the guest,
+ to ensure that the thread performing this work has as much CPU
+ occupancy as possible. For example when the DPDK sample application
+ `testpmd` is used to forward packets in the guest, multiple QEMU vCPU
+ threads can be created. Taskset can then be used to affinitize the
+ vCPU thread responsible for forwarding to a dedicated core not used
+ for other general processing on the host system.
+
+11. DPDK virtio pmd in the guest
+
+ dpdkvhostcuse or dpdkvhostuser ports can be used to accelerate the path
+ to the guest using the DPDK vhost library. This library is compatible with
+ virtio-net drivers in the guest but significantly better performance can
+ be observed when using the DPDK virtio pmd driver in the guest. The DPDK
+ `testpmd` application can be used in the guest as an example application
+ that forwards packet from one DPDK vhost port to another. An example of
+ running `testpmd` in the guest can be seen here.
+
+ ```
+ ./testpmd -c 0x3 -n 4 --socket-mem 512 -- --burst=64 -i --txqflags=0xf00
+ --disable-hw-vlan --forward-mode=io --auto-start
+ ```
+
+ See below information on dpdkvhostcuse and dpdkvhostuser ports.
+ See [DPDK Docs] for more information on `testpmd`.
DPDK Rings :
------------
DPDK vhost:
-----------
-DPDK 2.2 supports two types of vhost:
+DPDK 16.04 supports two types of vhost:
1. vhost-user
2. vhost-cuse
DPDK vhost-user Prerequisites:
-------------------------
-1. DPDK 2.2 with vhost support enabled as documented in the "Building and
+1. DPDK 16.04 with vhost support enabled as documented in the "Building and
Installing section"
2. QEMU version v2.1.0+
`/usr/local/var/run/openvswitch/vhost-user-1`, which you must provide
to your VM on the QEMU command line. More instructions on this can be
found in the next section "DPDK vhost-user VM configuration"
- Note: If you wish for the vhost-user sockets to be created in a
- directory other than `/usr/local/var/run/openvswitch`, you may specify
- another location on the ovs-vswitchd command line like so:
+ - If you wish for the vhost-user sockets to be created in a sub-directory of
+ `/usr/local/var/run/openvswitch`, you may specify this directory in the
+ ovsdb like so:
- `./vswitchd/ovs-vswitchd --dpdk -vhost_sock_dir /my-dir -c 0x1 ...`
+ `./utilities/ovs-vsctl --no-wait \
+ set Open_vSwitch . other_config:vhost-sock-dir=subdir`
DPDK vhost-user VM configuration:
---------------------------------
-device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2,mq=on,vectors=$v
```
+ If one wishes to use multiple queues for an interface in the guest, the
+ driver in the guest operating system must be configured to do so. It is
+ recommended that the number of queues configured be equal to '$q'.
+
+ For example, this can be done for the Linux kernel virtio-net driver with:
+
+ ```
+ ethtool -L <DEV> combined <$q>
+ ```
+
+ A note on the command above:
+
+ `-L`: Changes the numbers of channels of the specified network device
+
+ `combined`: Changes the number of multi-purpose channels.
+
DPDK vhost-cuse:
----------------
DPDK vhost-cuse Prerequisites:
-------------------------
-1. DPDK 2.2 with vhost support enabled as documented in the "Building and
+1. DPDK 16.04 with vhost support enabled as documented in the "Building and
Installing section"
As an additional step, you must enable vhost-cuse in DPDK by setting the
- following additional flag in `config/common_linuxapp`:
+ following additional flag in `config/common_base`:
`CONFIG_RTE_LIBRTE_VHOST_USER=n`
1. This step is only needed if using an alternative character device.
- The new character device filename must be specified on the vswitchd
- commandline:
+ The new character device filename must be specified in the ovsdb:
- `./vswitchd/ovs-vswitchd --dpdk --cuse_dev_name my-vhost-net -c 0x1 ...`
+ `./utilities/ovs-vsctl --no-wait set Open_vSwitch . \
+ other_config:cuse-dev-name=my-vhost-net`
- Note that the `--cuse_dev_name` argument and associated string must be the first
- arguments after `--dpdk` and come before the EAL arguments. In the example
- above, the character device to be used will be `/dev/my-vhost-net`.
+ In the example above, the character device to be used will be
+ `/dev/my-vhost-net`.
2. This step is only needed if reusing the standard character device. It will
conflict with the kernel vhost character device so the user must first
```
<my-vhost-device> refers to "vhost-net" if using the `/dev/vhost-net`
- device. If you have specificed a different name on the ovs-vswitchd
- commandline using the "--cuse_dev_name" parameter, please specify that
+ device. If you have specificed a different name in the database
+ using the "other_config:cuse-dev-name" parameter, please specify that
filename instead.
2. Disable SELinux or set to permissive mode
this with smaller page sizes.
Platform and Network Interface:
- - By default with DPDK 2.2, a maximum of 64 TX queues can be used with an
+ - By default with DPDK 16.04, a maximum of 64 TX queues can be used with an
Intel XL710 Network Interface on a platform with more than 64 logical
cores. If a user attempts to add an XL710 interface as a DPDK port type to
a system as described above, an error will be reported that initialization
increased to the desired number of queues. Both DPDK and OVS must be
recompiled for this change to take effect.
- vHost and QEMU v2.4.0+:
- - For versions of QEMU v2.4.0 and later, it is currently not possible to
- unbind more than one dpdkvhostuser port from the guest kernel driver
- without causing the ovs-vswitchd process to crash. If this is a requirement
- for your use case, it is recommended either to use a version of QEMU
- between v2.2.0 and v2.3.1 (inclusive), or alternatively, to apply the
- following patch to DPDK and rebuild:
- http://dpdk.org/dev/patchwork/patch/7736/
- This problem will likely be resolved in Open vSwitch at a later date, when
- the next release of DPDK (which includes the above patch) is available and
- integrated into OVS.
-
Bug Reporting:
--------------
projects / cascardo / ovs.git / blobdiff