openvswitch

Speeding up Open vSwitch with partial hardware offloading

Speeding up Open vSwitch with partial hardware offloading

Open vSwitch (OVS) can use the kernel datapath or the userspace datapath. There are interesting developments in the kernel datapath using hardware offloading through the TC Flower packet classifier, but in this article, the focus will be on the userspace datapath accelerated with the Data Plane Development Kit (DPDK) and its new feature—partial flow hardware offloading—to accelerate the virtual switch even more.

This article explains how the virtual switch worked before versus now and why the new feature can potentially save resources while improving the packet processing rate.

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Troubleshooting Open vSwitch DPDK PMD Thread Core Affinity

Troubleshooting Open vSwitch DPDK PMD Thread Core Affinity

The most common problem when people are trying to deploy an Open vSwitch with Data Plane Development Kit (OvS-DPDK) solution is that the performance is not as expected. For example, they are losing packets. This is where our journey for this series of blogs will start.

This first blog is about Poll Mode Driver (PMD) thread core affinity. It covers how to configure thread affinity and how to verify that it’s set up correctly. This includes making sure no other threads are using the CPU cores.

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Debugging Memory Issues with Open vSwitch DPDK

Debugging Memory Issues with Open vSwitch DPDK

Introduction

This article is about debugging out-of-memory issues with Open vSwitch with the Data Plane Development Kit (OvS-DPDK). It explains the situations in which you can run out of memory when using OvS-DPDK and it shows the log entries that are produced in those circumstances. It also shows some other log entries and commands for further debugging.

When you finish reading this article, you will be able to identify that you have an out-of-memory issue and you’ll know how to fix it. Spoiler: Usually having some more memory on the relevant NUMA node works. It is based on OvS 2.9.

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Open vSwitch-DPDK: How Much Hugepage Memory?

Open vSwitch-DPDK: How Much Hugepage Memory?

Introduction

In order to maximize performance of the Open vSwitch DPDK datapath, it pre-allocates hugepage memory. As a user you are responsible for telling Open vSwitch how much hugepage memory to pre-allocate. The question of exactly what value to use often arises. The answer is, it depends.

There is no simple answer as it depends on things like the MTU size of the ports, the MTU differences between ports, and whether those ports are on the same NUMA node. Just to complicate things a bit more, there are multiple overheads, and alignment and rounding need to be accounted for at various places in OVS-DPDK. Everything clear? OK, you can stop reading then!
However, if not, read on.

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Automated Open vSwitch PVP testing

Automated Open vSwitch PVP testing

This blog describes how a script can be used to automate Open vSwitch PVP testing. The goal for this PVP script was to have a quick (and dirty) way to verify the performance (change) of an Open vSwitch (DPDK) setup. This script either works with a Xena Networks traffic generator or the T-Rex Realistic Traffic Generator. For details on what the PVP test does, please refer to the following blog post, Measuring and comparing Open vSwitch performance.

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Open vSwitch: Overview of 802.1ad (QinQ) Support

Open vSwitch: Overview of 802.1ad (QinQ) Support

Open vSwitch (OVS) recently gained support for 802.1ad (QinQ). It can be used as a lightweight alternative to tunnel technologies such as; VXLAN, GENEVE, GRE. A key advantage of QinQ is that it can make use of hardware offload features common in network interface cards (NICs). Only newer NICs support hardware offload for VXLAN and GENEVE. QinQ also incurs less frame processing and has a smaller encapsulation overhead.

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Tracing packets inside Open vSwitch

Open vSwitch is a software switch responsible for providing network connectivity to virtual machines or containers. Since it is programmable, it brings a challenge to understand what is going on in the network. Open vSwitch (OVS) is an OpenFlow virtual switch, so before talking about OVS itself, it is necessary to introduce OpenFlow a bit.

OpenFlow is an open standard protocol that allows separation of the packet forwarding (data plane) from the high level routing decisions (control plane). The control plane (also known as OF controller) is responsible to provide instructions to the data plane (vswitch) on how to process packets.

The fact that each packet can have its own fate brings a new challenge to understand what is going on in the network. This article will show how to know what is happening with packets inside the vswitch.

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