Improving Network Performance in Multi-Core Systems

White Paper Improving Network Performance in Multi-Core Systems
2
Table of Contents
Solving the Problem ................................................................. 2
Multiple Descriptor Queues ...................................................................3
Receive-Side Scaling (RSS) .....................................................................3
Virtual Machine Device Queues (VMDq).........................................3
Extended Message-Signaled Interrupts (MSI-X) .......................3
Intel Network Controllers ....................................................... 4
Intel 82575 Gigabit Ethernet Controller ........................................4
Intel 82598 10 Gigabit Ethernet Controller .................................
4
Next Steps .................................................................................. 4
Performance impact cannot be improved by simply increasing the
bandwidth on the system. In fact, adding more network control-
lers only escalates the problem: larger numbers of packets cause
greater processing congestion for the CPU, and latencies climb
proportionately.
Solving the Problem
To address these performance issues, the Intel® 82575 Gigabit
Ethernet Controller and the Intel® 82598 10 Gigabit Ethernet
Controller rely on several key capabilities to distribute packet
processing across the cores. These technologies work in concert
to create independent packet queues, direct network packets
to the correct queue, map the queue to a processor core or
virtual machine, and facilitate the interaction between system,
queues, and cores.
The key technologies supported by these controllers include:
• Multiple descriptor queues
• Receive-Side Scaling (RSS)
• Virtual Machine Device Queues (VMDq)
• Extended Message-Signaled Interrupts (MSI-X)
These technologies are discussed in detail in the following sections.
MCH
LAN
Dual GbE
Port 1 Port 1
CPU
Figure 1. Network data flow in a previous-generation platform