Using Open vSwitch with DPDK
                   ============================

Open vSwitch can use Intel(R) DPDK lib to operate entirely in
userspace. This file explains how to install and use Open vSwitch in
such a mode.

The DPDK support of Open vSwitch is considered experimental.
It has not been thoroughly tested.

This version of Open vSwitch should be built manually with "configure"
and "make".

Building and Installing:
------------------------

Recommended to use DPDK 1.6.

DPDK:
cd DPDK
update config/defconfig_x86_64-default-linuxapp-gcc so that dpdk generate single lib file.
CONFIG_RTE_BUILD_COMBINE_LIBS=y

make install T=x86_64-default-linuxapp-gcc
For details refer to  http://dpdk.org/

Linux kernel:
Refer to intel-dpdk-getting-started-guide.pdf for understanding
DPDK kernel requirement.

OVS:
cd $(OVS_DIR)/openvswitch
./boot.sh
./configure --with-dpdk=$(DPDK_BUILD)
make

Refer to INSTALL.userspace for general requirements of building
userspace OVS.

Using the DPDK with ovs-vswitchd:
---------------------------------

First setup DPDK devices:
  - insert uio.ko
  - insert igb_uio.ko
    e.g. insmod DPDK/x86_64-default-linuxapp-gcc/kmod/igb_uio.ko
  - mount hugetlbfs
    e.g. mount -t hugetlbfs -o pagesize=1G none /mnt/huge/
  - Bind network device to ibg_uio.
    e.g. DPDK/tools/pci_unbind.py --bind=igb_uio eth1

Ref to http://www.dpdk.org/doc/quick-start for verifying DPDK setup.

Start vswitchd:
DPDK configuration arguments can be passed to vswitchd via `--dpdk`
argument. dpdk arg -c is ignored by ovs-dpdk, but it is required parameter
for dpdk initialization.

   e.g.
   ./vswitchd/ovs-vswitchd --dpdk -c 0x1 -n 4 -- unix:$DB_SOCK  --pidfile --detach

To use ovs-vswitchd with DPDK, create a bridge with datapath_type
"netdev" in the configuration database.  For example:

    ovs-vsctl add-br br0
    ovs-vsctl set bridge br0 datapath_type=netdev

Now you can add dpdk devices. OVS expect DPDK device name start with dpdk
and end with portid. vswitchd should print number of dpdk devices found.

    ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk

Once first DPDK port is added vswitchd, it creates Polling thread and
polls dpdk device in continuous loop. Therefore CPU utilization
for that thread is always 100%.

Restrictions:
-------------

  - This Support is for Physical NIC. I have tested with Intel NIC only.
  - vswitchd userspace datapath does affine polling thread but it is
    assumed that devices are on numa node 0. Therefore if device is
    attached to non zero numa node switching performance would be
    suboptimal.
  - There are fixed number of polling thread and fixed number of per
    device queues configured.
  - Work with 1500 MTU, needs few changes in DPDK lib to fix this issue.
  - Currently DPDK port does not make use any offload functionality.

Bug Reporting:
--------------

Please report problems to bugs@openvswitch.org.