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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/topics/dpdk/bridge.rst | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Documentation/topics/dpdk/bridge.rst b/Documentation/topics/dpdk/bridge.rst index b79d9871b..ceee91015 100644 --- a/Documentation/topics/dpdk/bridge.rst +++ b/Documentation/topics/dpdk/bridge.rst @@ -81,6 +81,30 @@ using the following command:: $ ovs-vsctl get Interface <iface> statistics +Simple Match Lookup +------------------- + +There are cases where users might want simple forwarding or drop rules for all +packets received from a specific port, e.g :: + + in_port=1,actions=2 + in_port=2,actions=IN_PORT + in_port=3,vlan_tci=0x1234/0x1fff,actions=drop + in_port=4,actions=push_vlan:0x8100,set_field:4196->vlan_vid,output:3 + +There are also cases where complex OpenFlow rules can be simplified down to +datapath flows with very simple match criteria. + +In theory, for very simple forwarding, OVS doesn't need to parse packets at all +in order to follow these rules. In practice, due to various implementation +constraints, userspace datapath has to match at least on a small set of packet +fileds. Some matching criteria (for example, ingress port) are not related to +the packet itself and others (for example, VLAN tag or Ethernet type) can be +extracted without fully parsing the packet. This allows OVS to significantly +speed up packet forwarding for these flows with simple match criteria. +Statistics on the number of packets matched in this way can be found in a +`simple match hits` counter of `ovs-appctl dpif-netdev/pmd-stats-show` command. + EMC Insertion Probability ------------------------- |