Building and Installing:
------------------------
-Required DPDK 1.8.0, `fuse`, `fuse-devel` (`libfuse-dev` on Debian/Ubuntu)
+Required: DPDK 2.0
+Optional (if building with vhost-cuse): `fuse`, `fuse-devel` (`libfuse-dev`
+on Debian/Ubuntu)
1. Configure build & install DPDK:
1. Set `$DPDK_DIR`
```
- export DPDK_DIR=/usr/src/dpdk-1.8.0
+ export DPDK_DIR=/usr/src/dpdk-2.0
cd $DPDK_DIR
```
`CONFIG_RTE_BUILD_COMBINE_LIBS=y`
Update `config/common_linuxapp` so that DPDK is built with vhost
- libraries:
+ libraries.
`CONFIG_RTE_LIBRTE_VHOST=y`
```
cd $(OVS_DIR)/openvswitch
./boot.sh
- ./configure --with-dpdk=$DPDK_BUILD
+ ./configure --with-dpdk=$DPDK_BUILD [CFLAGS="-g -O2 -Wno-cast-align"]
make
```
+ Note: 'clang' users may specify the '-Wno-cast-align' flag to suppress DPDK cast-align warnings.
+
To have better performance one can enable aggressive compiler optimizations and
use the special instructions(popcnt, crc32) that may not be available on all
machines. Instead of typing `make`, type:
1. insert uio.ko: `modprobe uio`
2. insert igb_uio.ko: `insmod $DPDK_BUILD/kmod/igb_uio.ko`
3. Bind network device to igb_uio:
- `$DPDK_DIR/tools/dpdk_nic_bind.py --bind=igb_uio eth1`
+ `$DPDK_DIR/tools/dpdk_nic_bind.py --bind=igb_uio eth1`
* VFIO:
2. Set correct permissions on vfio device: `sudo /usr/bin/chmod a+x /dev/vfio`
and: `sudo /usr/bin/chmod 0666 /dev/vfio/*`
3. Bind network device to vfio-pci:
- `$DPDK_DIR/tools/dpdk_nic_bind.py --bind=vfio-pci eth1`
+ `$DPDK_DIR/tools/dpdk_nic_bind.py --bind=vfio-pci eth1`
3. Mount the hugetable filsystem
polls dpdk device in continuous loop. Therefore CPU utilization
for that thread is always 100%.
+ Note: creating bonds of DPDK interfaces is slightly different to creating
+ bonds of system interfaces. For DPDK, the interface type must be explicitly
+ set, for example:
+
+ ```
+ ovs-vsctl add-bond br0 dpdkbond dpdk0 dpdk1 -- set Interface dpdk0 type=dpdk -- set Interface dpdk1 type=dpdk
+ ```
+
7. Add test flows
Test flow script across NICs (assuming ovs in /usr/src/ovs):
Note, the pmd threads on a numa node are only created if there is at least
one DPDK interface from the numa node that has been added to OVS.
- Note, core 0 is always reserved from non-pmd threads and should never be set
- in the cpu mask.
+ To understand where most of the time is spent and whether the caches are
+ effective, these commands can be used:
+
+ ```
+ ovs-appctl dpif-netdev/pmd-stats-clear #To reset statistics
+ ovs-appctl dpif-netdev/pmd-stats-show
+ ```
DPDK Rings :
------------
DPDK vhost:
-----------
-vhost-cuse is only supported at present i.e. not using the standard QEMU
-vhost-user interface. It is intended that vhost-user support will be added
-in future releases when supported in DPDK and that vhost-cuse will eventually
-be deprecated. See [DPDK Docs] for more info on vhost.
+DPDK 2.0 supports two types of vhost:
+
+1. vhost-user
+2. vhost-cuse
+
+Whatever type of vhost is enabled in the DPDK build specified, is the type
+that will be enabled in OVS. By default, vhost-user is enabled in DPDK.
+Therefore, unless vhost-cuse has been enabled in DPDK, vhost-user ports
+will be enabled in OVS.
+Please note that support for vhost-cuse is intended to be deprecated in OVS
+in a future release.
+
+DPDK vhost-user:
+----------------
+
+The following sections describe the use of vhost-user 'dpdkvhostuser' ports
+with OVS.
+
+DPDK vhost-user Prerequisites:
+-------------------------
+
+1. DPDK 2.0 with vhost support enabled as documented in the "Building and
+ Installing section"
+
+2. QEMU version v2.1.0+
-Prerequisites:
-1. Insert the Cuse module:
+ QEMU v2.1.0 will suffice, but it is recommended to use v2.2.0 if providing
+ your VM with memory greater than 1GB due to potential issues with memory
+ mapping larger areas.
- `modprobe cuse`
+Adding DPDK vhost-user ports to the Switch:
+--------------------------------------
-2. Build and insert the `eventfd_link` module:
+Following the steps above to create a bridge, you can now add DPDK vhost-user
+as a port to the vswitch. Unlike DPDK ring ports, DPDK vhost-user ports can
+have arbitrary names.
- `cd $DPDK_DIR/lib/librte_vhost/eventfd_link/`
- `make`
- `insmod $DPDK_DIR/lib/librte_vhost/eventfd_link.ko`
+ - For vhost-user, the name of the port type is `dpdkvhostuser`
-Following the steps above to create a bridge, you can now add DPDK vhost
-as a port to the vswitch.
+ ```
+ ovs-vsctl add-port br0 vhost-user-1 -- set Interface vhost-user-1
+ type=dpdkvhostuser
+ ```
+
+ This action creates a socket located at
+ `/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:
+
+ `./vswitchd/ovs-vswitchd --dpdk -vhost_sock_dir /my-dir -c 0x1 ...`
-`ovs-vsctl add-port br0 dpdkvhost0 -- set Interface dpdkvhost0 type=dpdkvhost`
+DPDK vhost-user VM configuration:
+---------------------------------
+Follow the steps below to attach vhost-user port(s) to a VM.
-Unlike DPDK ring ports, DPDK vhost ports can have arbitrary names:
+1. Configure sockets.
+ Pass the following parameters to QEMU to attach a vhost-user device:
-`ovs-vsctl add-port br0 port123ABC -- set Interface port123ABC type=dpdkvhost`
+ ```
+ -chardev socket,id=char1,path=/usr/local/var/run/openvswitch/vhost-user-1
+ -netdev type=vhost-user,id=mynet1,chardev=char1,vhostforce
+ -device virtio-net-pci,mac=00:00:00:00:00:01,netdev=mynet1
+ ```
-However, please note that when attaching userspace devices to QEMU, the
-name provided during the add-port operation must match the ifname parameter
-on the QEMU command line.
+ ...where vhost-user-1 is the name of the vhost-user port added
+ to the switch.
+ Repeat the above parameters for multiple devices, changing the
+ chardev path and id as necessary. Note that a separate and different
+ chardev path needs to be specified for each vhost-user device. For
+ example you have a second vhost-user port named 'vhost-user-2', you
+ append your QEMU command line with an additional set of parameters:
+ ```
+ -chardev socket,id=char2,path=/usr/local/var/run/openvswitch/vhost-user-2
+ -netdev type=vhost-user,id=mynet2,chardev=char2,vhostforce
+ -device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2
+ ```
+
+2. Configure huge pages.
+ QEMU must allocate the VM's memory on hugetlbfs. vhost-user ports access
+ a virtio-net device's virtual rings and packet buffers mapping the VM's
+ physical memory on hugetlbfs. To enable vhost-user ports to map the VM's
+ memory into their process address space, pass the following paramters
+ to QEMU:
+
+ ```
+ -object memory-backend-file,id=mem,size=4096M,mem-path=/dev/hugepages,
+ share=on
+ -numa node,memdev=mem -mem-prealloc
+ ```
-DPDK vhost VM configuration:
-----------------------------
+DPDK vhost-cuse:
+----------------
- vhost ports use a Linux* character device to communicate with QEMU.
+The following sections describe the use of vhost-cuse 'dpdkvhostcuse' ports
+with OVS.
+
+DPDK vhost-cuse Prerequisites:
+-------------------------
+
+1. DPDK 2.0 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`:
+
+ `CONFIG_RTE_LIBRTE_VHOST_USER=n`
+
+ Following this, rebuild DPDK as per the instructions in the "Building and
+ Installing" section. Finally, rebuild OVS as per step 3 in the "Building
+ and Installing" section - OVS will detect that DPDK has vhost-cuse libraries
+ compiled and in turn will enable support for it in the switch and disable
+ vhost-user support.
+
+2. Insert the Cuse module:
+
+ `modprobe cuse`
+
+3. Build and insert the `eventfd_link` module:
+
+ ```
+ cd $DPDK_DIR/lib/librte_vhost/eventfd_link/
+ make
+ insmod $DPDK_DIR/lib/librte_vhost/eventfd_link.ko
+ ```
+
+4. QEMU version v2.1.0+
+
+ vhost-cuse will work with QEMU v2.1.0 and above, however it is recommended to
+ use v2.2.0 if providing your VM with memory greater than 1GB due to potential
+ issues with memory mapping larger areas.
+ Note: QEMU v1.6.2 will also work, with slightly different command line parameters,
+ which are specified later in this document.
+
+Adding DPDK vhost-cuse ports to the Switch:
+--------------------------------------
+
+Following the steps above to create a bridge, you can now add DPDK vhost-cuse
+as a port to the vswitch. Unlike DPDK ring ports, DPDK vhost-cuse ports can have
+arbitrary names.
+
+ - For vhost-cuse, the name of the port type is `dpdkvhostcuse`
+
+ ```
+ ovs-vsctl add-port br0 vhost-cuse-1 -- set Interface vhost-cuse-1
+ type=dpdkvhostcuse
+ ```
+
+ When attaching vhost-cuse ports to QEMU, the name provided during the
+ add-port operation must match the ifname parameter on the QEMU command
+ line. More instructions on this can be found in the next section.
+
+DPDK vhost-cuse VM configuration:
+---------------------------------
+
+ vhost-cuse ports use a Linux* character device to communicate with QEMU.
By default it is set to `/dev/vhost-net`. It is possible to reuse this
standard device for DPDK vhost, which makes setup a little simpler but it
is better practice to specify an alternative character device in order to
subprocess.call("qemu-system-x86_64 .... -netdev tap,id=vhostnet0,\
vhost=on,vhostfd=" + fd +"...", shell=True)
- Alternatively the the `qemu-wrap.py` script can be used to automate the
+ Alternatively the `qemu-wrap.py` script can be used to automate the
requirements specified above and can be used in conjunction with libvirt if
desired. See the "DPDK vhost VM configuration with QEMU wrapper" section
below.
QEMU must allocate the VM's memory on hugetlbfs. Vhost ports access a
virtio-net device's virtual rings and packet buffers mapping the VM's
physical memory on hugetlbfs. To enable vhost-ports to map the VM's
- memory into their process address space, pass the following paramters
+ memory into their process address space, pass the following parameters
to QEMU:
`-object memory-backend-file,id=mem,size=4096M,mem-path=/dev/hugepages,
share=on -numa node,memdev=mem -mem-prealloc`
+ Note: For use with an earlier QEMU version such as v1.6.2, use the
+ following to configure hugepages instead:
-DPDK vhost VM configuration with QEMU wrapper:
-----------------------------------------------
+ `-mem-path /dev/hugepages -mem-prealloc`
+DPDK vhost-cuse VM configuration with QEMU wrapper:
+---------------------------------------------------
The QEMU wrapper script automatically detects and calls QEMU with the
necessary parameters. It performs the following actions:
netdev=net1,mac=00:00:00:00:00:01
```
-DPDK vhost VM configuration with libvirt:
------------------------------------------
+DPDK vhost-cuse VM configuration with libvirt:
+----------------------------------------------
If you are using libvirt, you must enable libvirt to access the character
device by adding it to controllers cgroup for libvirtd using the following
`virsh create my_vhost_vm.xml`
-DPDK vhost VM configuration with libvirt and QEMU wrapper:
+DPDK vhost-cuse VM configuration with libvirt and QEMU wrapper:
----------------------------------------------------------
To use the qemu-wrapper script in conjuntion with libvirt, follow the
the correct emulator location and set any additional options. If you are
using a alternative character device name, please set "us_vhost_path" to the
location of that device. The script will automatically detect and insert
- the correct "vhostfd" value in the QEMU command line arguements.
+ the correct "vhostfd" value in the QEMU command line arguments.
5. Use virt-manager to launch the VM
+Running ovs-vswitchd with DPDK backend inside a VM
+--------------------------------------------------
+
+Please note that 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:
+
+`<driver name='vhost' queues='N'/>`
+
+to <interface> sections of all network devices used by DPDK. Parameter 'N'
+determines how many queues can be used by the guest.
+
Restrictions:
-------------
- DPDK-vHost support works with 1G huge pages.
ivshmem:
- - The shared memory is currently restricted to the use of a 1GB
- huge pages.
- - All huge pages are shared amongst the host, clients, virtual
- machines etc.
+ - If you run Open vSwitch with smaller page sizes (e.g. 2MB), you may be
+ unable to share any rings or mempools with a virtual machine.
+ This is because the current implementation of ivshmem works by sharing
+ a single 1GB huge page from the host operating system to any guest
+ operating system through the Qemu ivshmem device. When using smaller
+ page sizes, multiple pages may be required to hold the ring descriptors
+ and buffer pools. The Qemu ivshmem device does not allow you to share
+ multiple file descriptors to the guest operating system. However, if you
+ want to share dpdkr rings with other processes on the host, you can do
+ this with smaller page sizes.
+
+ Platform and Network Interface:
+ - Currently it is not possible to use an Intel XL710 Network Interface as a
+ DPDK port type on a platform with more than 64 logical cores. This is
+ related to how DPDK reports the number of TX queues that may be used by
+ a DPDK application with an XL710. The maximum number of TX queues supported
+ by a DPDK application for an XL710 is 64. If a user attempts to add an
+ XL710 interface as a DPDK port type to a system as described above the
+ port addition will fail as OVS will attempt to initialize a TX queue greater
+ than 64. This issue is expected to be resolved in a future DPDK release.
+ As a workaround a user can disable hyper-threading to reduce the overall
+ core count of the system to be less than or equal to 64 when using an XL710
+ interface with DPDK.
Bug Reporting:
--------------
projects / cascardo / ovs.git / blobdiff