X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Fintel_vf.rst;fp=doc%2Fguides%2Fnics%2Fintel_vf.rst;h=a68198f882947cfb1c7e5ccaab47af5724b8fa9c;hb=97f17497d162afdb82c8704bf097f0fee3724b2e;hp=0000000000000000000000000000000000000000;hpb=e04be89c2409570e0055b2cda60bd11395bb93b0;p=deb_dpdk.git diff --git a/doc/guides/nics/intel_vf.rst b/doc/guides/nics/intel_vf.rst new file mode 100644 index 00000000..a68198f8 --- /dev/null +++ b/doc/guides/nics/intel_vf.rst @@ -0,0 +1,608 @@ +.. BSD LICENSE + Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + * Neither the name of Intel Corporation nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +I40E/IXGBE/IGB Virtual Function Driver +====================================== + +Supported Intel® Ethernet Controllers (see the *DPDK Release Notes* for details) +support the following modes of operation in a virtualized environment: + +* **SR-IOV mode**: Involves direct assignment of part of the port resources to different guest operating systems + using the PCI-SIG Single Root I/O Virtualization (SR IOV) standard, + also known as "native mode" or "pass-through" mode. + In this chapter, this mode is referred to as IOV mode. + +* **VMDq mode**: Involves central management of the networking resources by an IO Virtual Machine (IOVM) or + a Virtual Machine Monitor (VMM), also known as software switch acceleration mode. + In this chapter, this mode is referred to as the Next Generation VMDq mode. + +SR-IOV Mode Utilization in a DPDK Environment +--------------------------------------------- + +The DPDK uses the SR-IOV feature for hardware-based I/O sharing in IOV mode. +Therefore, it is possible to partition SR-IOV capability on Ethernet controller NIC resources logically and +expose them to a virtual machine as a separate PCI function called a "Virtual Function". +Refer to :numref:`figure_single_port_nic`. + +Therefore, a NIC is logically distributed among multiple virtual machines (as shown in :numref:`figure_single_port_nic`), +while still having global data in common to share with the Physical Function and other Virtual Functions. +The DPDK fm10kvf, i40evf, igbvf or ixgbevf as a Poll Mode Driver (PMD) serves for the Intel® 82576 Gigabit Ethernet Controller, +Intel® Ethernet Controller I350 family, Intel® 82599 10 Gigabit Ethernet Controller NIC, +Intel® Fortville 10/40 Gigabit Ethernet Controller NIC's virtual PCI function, or PCIe host-interface of the Intel Ethernet Switch +FM10000 Series. +Meanwhile the DPDK Poll Mode Driver (PMD) also supports "Physical Function" of such NIC's on the host. + +The DPDK PF/VF Poll Mode Driver (PMD) supports the Layer 2 switch on Intel® 82576 Gigabit Ethernet Controller, +Intel® Ethernet Controller I350 family, Intel® 82599 10 Gigabit Ethernet Controller, +and Intel® Fortville 10/40 Gigabit Ethernet Controller NICs so that guest can choose it for inter virtual machine traffic in SR-IOV mode. + +For more detail on SR-IOV, please refer to the following documents: + +* `SR-IOV provides hardware based I/O sharing `_ + +* `PCI-SIG-Single Root I/O Virtualization Support on IA + `_ + +* `Scalable I/O Virtualized Servers `_ + +.. _figure_single_port_nic: + +.. figure:: img/single_port_nic.* + + Virtualization for a Single Port NIC in SR-IOV Mode + + +Physical and Virtual Function Infrastructure +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The following describes the Physical Function and Virtual Functions infrastructure for the supported Ethernet Controller NICs. + +Virtual Functions operate under the respective Physical Function on the same NIC Port and therefore have no access +to the global NIC resources that are shared between other functions for the same NIC port. + +A Virtual Function has basic access to the queue resources and control structures of the queues assigned to it. +For global resource access, a Virtual Function has to send a request to the Physical Function for that port, +and the Physical Function operates on the global resources on behalf of the Virtual Function. +For this out-of-band communication, an SR-IOV enabled NIC provides a memory buffer for each Virtual Function, +which is called a "Mailbox". + +The PCIE host-interface of Intel Ethernet Switch FM10000 Series VF infrastructure +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In a virtualized environment, the programmer can enable a maximum of *64 Virtual Functions (VF)* +globally per PCIE host-interface of the Intel Ethernet Switch FM10000 Series device. +Each VF can have a maximum of 16 queue pairs. +The Physical Function in host could be only configured by the Linux* fm10k driver +(in the case of the Linux Kernel-based Virtual Machine [KVM]), DPDK PMD PF driver doesn't support it yet. + +For example, + +* Using Linux* fm10k driver: + + .. code-block:: console + + rmmod fm10k (To remove the fm10k module) + insmod fm0k.ko max_vfs=2,2 (To enable two Virtual Functions per port) + +Virtual Function enumeration is performed in the following sequence by the Linux* pci driver for a dual-port NIC. +When you enable the four Virtual Functions with the above command, the four enabled functions have a Function# +represented by (Bus#, Device#, Function#) in sequence starting from 0 to 3. +However: + +* Virtual Functions 0 and 2 belong to Physical Function 0 + +* Virtual Functions 1 and 3 belong to Physical Function 1 + +.. note:: + + The above is an important consideration to take into account when targeting specific packets to a selected port. + +Intel® Fortville 10/40 Gigabit Ethernet Controller VF Infrastructure +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In a virtualized environment, the programmer can enable a maximum of *128 Virtual Functions (VF)* +globally per Intel® Fortville 10/40 Gigabit Ethernet Controller NIC device. +Each VF can have a maximum of 16 queue pairs. +The Physical Function in host could be either configured by the Linux* i40e driver +(in the case of the Linux Kernel-based Virtual Machine [KVM]) or by DPDK PMD PF driver. +When using both DPDK PMD PF/VF drivers, the whole NIC will be taken over by DPDK based application. + +For example, + +* Using Linux* i40e driver: + + .. code-block:: console + + rmmod i40e (To remove the i40e module) + insmod i40e.ko max_vfs=2,2 (To enable two Virtual Functions per port) + +* Using the DPDK PMD PF i40e driver: + + Kernel Params: iommu=pt, intel_iommu=on + + .. code-block:: console + + modprobe uio + insmod igb_uio + ./dpdk_nic_bind.py -b igb_uio bb:ss.f + echo 2 > /sys/bus/pci/devices/0000\:bb\:ss.f/max_vfs (To enable two VFs on a specific PCI device) + + Launch the DPDK testpmd/example or your own host daemon application using the DPDK PMD library. + +* Using the DPDK PMD PF ixgbe driver to enable VF RSS: + + Same steps as above to install the modules of uio, igb_uio, specify max_vfs for PCI device, and + launch the DPDK testpmd/example or your own host daemon application using the DPDK PMD library. + + The available queue number(at most 4) per VF depends on the total number of pool, which is + determined by the max number of VF at PF initialization stage and the number of queue specified + in config: + + * If the max number of VF is set in the range of 1 to 32: + + If the number of rxq is specified as 4(e.g. '--rxq 4' in testpmd), then there are totally 32 + pools(ETH_32_POOLS), and each VF could have 4 or less(e.g. 2) queues; + + If the number of rxq is specified as 2(e.g. '--rxq 2' in testpmd), then there are totally 32 + pools(ETH_32_POOLS), and each VF could have 2 queues; + + * If the max number of VF is in the range of 33 to 64: + + If the number of rxq is 4 ('--rxq 4' in testpmd), then error message is expected as rxq is not + correct at this case; + + If the number of rxq is 2 ('--rxq 2' in testpmd), then there is totally 64 pools(ETH_64_POOLS), + and each VF have 2 queues; + + On host, to enable VF RSS functionality, rx mq mode should be set as ETH_MQ_RX_VMDQ_RSS + or ETH_MQ_RX_RSS mode, and SRIOV mode should be activated(max_vfs >= 1). + It also needs config VF RSS information like hash function, RSS key, RSS key length. + + .. code-block:: console + + testpmd -c 0xffff -n 4 -- --coremask= --rxq=4 --txq=4 -i + + The limitation for VF RSS on Intel® 82599 10 Gigabit Ethernet Controller is: + The hash and key are shared among PF and all VF, the RETA table with 128 entries is also shared + among PF and all VF; So it could not to provide a method to query the hash and reta content per + VF on guest, while, if possible, please query them on host(PF) for the shared RETA information. + +Virtual Function enumeration is performed in the following sequence by the Linux* pci driver for a dual-port NIC. +When you enable the four Virtual Functions with the above command, the four enabled functions have a Function# +represented by (Bus#, Device#, Function#) in sequence starting from 0 to 3. +However: + +* Virtual Functions 0 and 2 belong to Physical Function 0 + +* Virtual Functions 1 and 3 belong to Physical Function 1 + +.. note:: + + The above is an important consideration to take into account when targeting specific packets to a selected port. + +Intel® 82599 10 Gigabit Ethernet Controller VF Infrastructure +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +The programmer can enable a maximum of *63 Virtual Functions* and there must be *one Physical Function* per Intel® 82599 +10 Gigabit Ethernet Controller NIC port. +The reason for this is that the device allows for a maximum of 128 queues per port and a virtual/physical function has to +have at least one queue pair (RX/TX). +The current implementation of the DPDK ixgbevf driver supports a single queue pair (RX/TX) per Virtual Function. +The Physical Function in host could be either configured by the Linux* ixgbe driver +(in the case of the Linux Kernel-based Virtual Machine [KVM]) or by DPDK PMD PF driver. +When using both DPDK PMD PF/VF drivers, the whole NIC will be taken over by DPDK based application. + +For example, + +* Using Linux* ixgbe driver: + + .. code-block:: console + + rmmod ixgbe (To remove the ixgbe module) + insmod ixgbe max_vfs=2,2 (To enable two Virtual Functions per port) + +* Using the DPDK PMD PF ixgbe driver: + + Kernel Params: iommu=pt, intel_iommu=on + + .. code-block:: console + + modprobe uio + insmod igb_uio + ./dpdk_nic_bind.py -b igb_uio bb:ss.f + echo 2 > /sys/bus/pci/devices/0000\:bb\:ss.f/max_vfs (To enable two VFs on a specific PCI device) + + Launch the DPDK testpmd/example or your own host daemon application using the DPDK PMD library. + +Virtual Function enumeration is performed in the following sequence by the Linux* pci driver for a dual-port NIC. +When you enable the four Virtual Functions with the above command, the four enabled functions have a Function# +represented by (Bus#, Device#, Function#) in sequence starting from 0 to 3. +However: + +* Virtual Functions 0 and 2 belong to Physical Function 0 + +* Virtual Functions 1 and 3 belong to Physical Function 1 + +.. note:: + + The above is an important consideration to take into account when targeting specific packets to a selected port. + +Intel® 82576 Gigabit Ethernet Controller and Intel® Ethernet Controller I350 Family VF Infrastructure +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In a virtualized environment, an Intel® 82576 Gigabit Ethernet Controller serves up to eight virtual machines (VMs). +The controller has 16 TX and 16 RX queues. +They are generally referred to (or thought of) as queue pairs (one TX and one RX queue). +This gives the controller 16 queue pairs. + +A pool is a group of queue pairs for assignment to the same VF, used for transmit and receive operations. +The controller has eight pools, with each pool containing two queue pairs, that is, two TX and two RX queues assigned to each VF. + +In a virtualized environment, an Intel® Ethernet Controller I350 family device serves up to eight virtual machines (VMs) per port. +The eight queues can be accessed by eight different VMs if configured correctly (the i350 has 4x1GbE ports each with 8T X and 8 RX queues), +that means, one Transmit and one Receive queue assigned to each VF. + +For example, + +* Using Linux* igb driver: + + .. code-block:: console + + rmmod igb (To remove the igb module) + insmod igb max_vfs=2,2 (To enable two Virtual Functions per port) + +* Using DPDK PMD PF igb driver: + + Kernel Params: iommu=pt, intel_iommu=on modprobe uio + + .. code-block:: console + + insmod igb_uio + ./dpdk_nic_bind.py -b igb_uio bb:ss.f + echo 2 > /sys/bus/pci/devices/0000\:bb\:ss.f/max_vfs (To enable two VFs on a specific pci device) + + Launch DPDK testpmd/example or your own host daemon application using the DPDK PMD library. + +Virtual Function enumeration is performed in the following sequence by the Linux* pci driver for a four-port NIC. +When you enable the four Virtual Functions with the above command, the four enabled functions have a Function# +represented by (Bus#, Device#, Function#) in sequence, starting from 0 to 7. +However: + +* Virtual Functions 0 and 4 belong to Physical Function 0 + +* Virtual Functions 1 and 5 belong to Physical Function 1 + +* Virtual Functions 2 and 6 belong to Physical Function 2 + +* Virtual Functions 3 and 7 belong to Physical Function 3 + +.. note:: + + The above is an important consideration to take into account when targeting specific packets to a selected port. + +Validated Hypervisors +~~~~~~~~~~~~~~~~~~~~~ + +The validated hypervisor is: + +* KVM (Kernel Virtual Machine) with Qemu, version 0.14.0 + +However, the hypervisor is bypassed to configure the Virtual Function devices using the Mailbox interface, +the solution is hypervisor-agnostic. +Xen* and VMware* (when SR- IOV is supported) will also be able to support the DPDK with Virtual Function driver support. + +Expected Guest Operating System in Virtual Machine +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The expected guest operating systems in a virtualized environment are: + +* Fedora* 14 (64-bit) + +* Ubuntu* 10.04 (64-bit) + +For supported kernel versions, refer to the *DPDK Release Notes*. + +Setting Up a KVM Virtual Machine Monitor +---------------------------------------- + +The following describes a target environment: + +* Host Operating System: Fedora 14 + +* Hypervisor: KVM (Kernel Virtual Machine) with Qemu version 0.14.0 + +* Guest Operating System: Fedora 14 + +* Linux Kernel Version: Refer to the *DPDK Getting Started Guide* + +* Target Applications: l2fwd, l3fwd-vf + +The setup procedure is as follows: + +#. Before booting the Host OS, open **BIOS setup** and enable **Intel® VT features**. + +#. While booting the Host OS kernel, pass the intel_iommu=on kernel command line argument using GRUB. + When using DPDK PF driver on host, pass the iommu=pt kernel command line argument in GRUB. + +#. Download qemu-kvm-0.14.0 from + `http://sourceforge.net/projects/kvm/files/qemu-kvm/ `_ + and install it in the Host OS using the following steps: + + When using a recent kernel (2.6.25+) with kvm modules included: + + .. code-block:: console + + tar xzf qemu-kvm-release.tar.gz + cd qemu-kvm-release + ./configure --prefix=/usr/local/kvm + make + sudo make install + sudo /sbin/modprobe kvm-intel + + When using an older kernel, or a kernel from a distribution without the kvm modules, + you must download (from the same link), compile and install the modules yourself: + + .. code-block:: console + + tar xjf kvm-kmod-release.tar.bz2 + cd kvm-kmod-release + ./configure + make + sudo make install + sudo /sbin/modprobe kvm-intel + + qemu-kvm installs in the /usr/local/bin directory. + + For more details about KVM configuration and usage, please refer to: + + `http://www.linux-kvm.org/page/HOWTO1 `_. + +#. Create a Virtual Machine and install Fedora 14 on the Virtual Machine. + This is referred to as the Guest Operating System (Guest OS). + +#. Download and install the latest ixgbe driver from: + + `http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=14687 `_ + +#. In the Host OS + + When using Linux kernel ixgbe driver, unload the Linux ixgbe driver and reload it with the max_vfs=2,2 argument: + + .. code-block:: console + + rmmod ixgbe + modprobe ixgbe max_vfs=2,2 + + When using DPDK PMD PF driver, insert DPDK kernel module igb_uio and set the number of VF by sysfs max_vfs: + + .. code-block:: console + + modprobe uio + insmod igb_uio + ./dpdk_nic_bind.py -b igb_uio 02:00.0 02:00.1 0e:00.0 0e:00.1 + echo 2 > /sys/bus/pci/devices/0000\:02\:00.0/max_vfs + echo 2 > /sys/bus/pci/devices/0000\:02\:00.1/max_vfs + echo 2 > /sys/bus/pci/devices/0000\:0e\:00.0/max_vfs + echo 2 > /sys/bus/pci/devices/0000\:0e\:00.1/max_vfs + + .. note:: + + You need to explicitly specify number of vfs for each port, for example, + in the command above, it creates two vfs for the first two ixgbe ports. + + Let say we have a machine with four physical ixgbe ports: + + + 0000:02:00.0 + + 0000:02:00.1 + + 0000:0e:00.0 + + 0000:0e:00.1 + + The command above creates two vfs for device 0000:02:00.0: + + .. code-block:: console + + ls -alrt /sys/bus/pci/devices/0000\:02\:00.0/virt* + lrwxrwxrwx. 1 root root 0 Apr 13 05:40 /sys/bus/pci/devices/0000:02:00.0/virtfn1 -> ../0000:02:10.2 + lrwxrwxrwx. 1 root root 0 Apr 13 05:40 /sys/bus/pci/devices/0000:02:00.0/virtfn0 -> ../0000:02:10.0 + + It also creates two vfs for device 0000:02:00.1: + + .. code-block:: console + + ls -alrt /sys/bus/pci/devices/0000\:02\:00.1/virt* + lrwxrwxrwx. 1 root root 0 Apr 13 05:51 /sys/bus/pci/devices/0000:02:00.1/virtfn1 -> ../0000:02:10.3 + lrwxrwxrwx. 1 root root 0 Apr 13 05:51 /sys/bus/pci/devices/0000:02:00.1/virtfn0 -> ../0000:02:10.1 + +#. List the PCI devices connected and notice that the Host OS shows two Physical Functions (traditional ports) + and four Virtual Functions (two for each port). + This is the result of the previous step. + +#. Insert the pci_stub module to hold the PCI devices that are freed from the default driver using the following command + (see http://www.linux-kvm.org/page/How_to_assign_devices_with_VT-d_in_KVM Section 4 for more information): + + .. code-block:: console + + sudo /sbin/modprobe pci-stub + + Unbind the default driver from the PCI devices representing the Virtual Functions. + A script to perform this action is as follows: + + .. code-block:: console + + echo "8086 10ed" > /sys/bus/pci/drivers/pci-stub/new_id + echo 0000:08:10.0 > /sys/bus/pci/devices/0000:08:10.0/driver/unbind + echo 0000:08:10.0 > /sys/bus/pci/drivers/pci-stub/bind + + where, 0000:08:10.0 belongs to the Virtual Function visible in the Host OS. + +#. Now, start the Virtual Machine by running the following command: + + .. code-block:: console + + /usr/local/kvm/bin/qemu-system-x86_64 -m 4096 -smp 4 -boot c -hda lucid.qcow2 -device pci-assign,host=08:10.0 + + where: + + — -m = memory to assign + + — -smp = number of smp cores + + — -boot = boot option + + — -hda = virtual disk image + + — -device = device to attach + + .. note:: + + — The pci-assign,host=08:10.0 alue indicates that you want to attach a PCI device + to a Virtual Machine and the respective (Bus:Device.Function) + numbers should be passed for the Virtual Function to be attached. + + — qemu-kvm-0.14.0 allows a maximum of four PCI devices assigned to a VM, + but this is qemu-kvm version dependent since qemu-kvm-0.14.1 allows a maximum of five PCI devices. + + — qemu-system-x86_64 also has a -cpu command line option that is used to select the cpu_model + to emulate in a Virtual Machine. Therefore, it can be used as: + + .. code-block:: console + + /usr/local/kvm/bin/qemu-system-x86_64 -cpu ? + + (to list all available cpu_models) + + /usr/local/kvm/bin/qemu-system-x86_64 -m 4096 -cpu host -smp 4 -boot c -hda lucid.qcow2 -device pci-assign,host=08:10.0 + + (to use the same cpu_model equivalent to the host cpu) + + For more information, please refer to: `http://wiki.qemu.org/Features/CPUModels `_. + +#. Install and run DPDK host app to take over the Physical Function. Eg. + + .. code-block:: console + + make install T=x86_64-native-linuxapp-gcc + ./x86_64-native-linuxapp-gcc/app/testpmd -c f -n 4 -- -i + +#. Finally, access the Guest OS using vncviewer with the localhost:5900 port and check the lspci command output in the Guest OS. + The virtual functions will be listed as available for use. + +#. Configure and install the DPDK with an x86_64-native-linuxapp-gcc configuration on the Guest OS as normal, + that is, there is no change to the normal installation procedure. + + .. code-block:: console + + make config T=x86_64-native-linuxapp-gcc O=x86_64-native-linuxapp-gcc + cd x86_64-native-linuxapp-gcc + make + +.. note:: + + If you are unable to compile the DPDK and you are getting "error: CPU you selected does not support x86-64 instruction set", + power off the Guest OS and start the virtual machine with the correct -cpu option in the qemu- system-x86_64 command as shown in step 9. + You must select the best x86_64 cpu_model to emulate or you can select host option if available. + +.. note:: + + Run the DPDK l2fwd sample application in the Guest OS with Hugepages enabled. + For the expected benchmark performance, you must pin the cores from the Guest OS to the Host OS (taskset can be used to do this) and + you must also look at the PCI Bus layout on the board to ensure you are not running the traffic over the QPI Interface. + +.. note:: + + * The Virtual Machine Manager (the Fedora package name is virt-manager) is a utility for virtual machine management + that can also be used to create, start, stop and delete virtual machines. + If this option is used, step 2 and 6 in the instructions provided will be different. + + * virsh, a command line utility for virtual machine management, + can also be used to bind and unbind devices to a virtual machine in Ubuntu. + If this option is used, step 6 in the instructions provided will be different. + + * The Virtual Machine Monitor (see :numref:`figure_perf_benchmark`) is equivalent to a Host OS with KVM installed as described in the instructions. + +.. _figure_perf_benchmark: + +.. figure:: img/perf_benchmark.* + + Performance Benchmark Setup + + +DPDK SR-IOV PMD PF/VF Driver Usage Model +---------------------------------------- + +Fast Host-based Packet Processing +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Software Defined Network (SDN) trends are demanding fast host-based packet handling. +In a virtualization environment, +the DPDK VF PMD driver performs the same throughput result as a non-VT native environment. + +With such host instance fast packet processing, lots of services such as filtering, QoS, +DPI can be offloaded on the host fast path. + +:numref:`figure_fast_pkt_proc` shows the scenario where some VMs directly communicate externally via a VFs, +while others connect to a virtual switch and share the same uplink bandwidth. + +.. _figure_fast_pkt_proc: + +.. figure:: img/fast_pkt_proc.* + + Fast Host-based Packet Processing + + +SR-IOV (PF/VF) Approach for Inter-VM Communication +-------------------------------------------------- + +Inter-VM data communication is one of the traffic bottle necks in virtualization platforms. +SR-IOV device assignment helps a VM to attach the real device, taking advantage of the bridge in the NIC. +So VF-to-VF traffic within the same physical port (VM0<->VM1) have hardware acceleration. +However, when VF crosses physical ports (VM0<->VM2), there is no such hardware bridge. +In this case, the DPDK PMD PF driver provides host forwarding between such VMs. + +:numref:`figure_inter_vm_comms` shows an example. +In this case an update of the MAC address lookup tables in both the NIC and host DPDK application is required. + +In the NIC, writing the destination of a MAC address belongs to another cross device VM to the PF specific pool. +So when a packet comes in, its destination MAC address will match and forward to the host DPDK PMD application. + +In the host DPDK application, the behavior is similar to L2 forwarding, +that is, the packet is forwarded to the correct PF pool. +The SR-IOV NIC switch forwards the packet to a specific VM according to the MAC destination address +which belongs to the destination VF on the VM. + +.. _figure_inter_vm_comms: + +.. figure:: img/inter_vm_comms.* + + Inter-VM Communication