Generic Segmentation Offload Tests

Overview

Generic Segmentation Offload (GSO) reduces per-packet processing overhead by enabling applications to pass a multi-packet buffer to (v)NIC and process a smaller number of large packets (e.g. frame size of 64 KB), instead of processing higher numbers of small packets (e.g. frame size of 1500 B), thus reducing per-packet overhead.

CSIT-2106 introduced GSO tests for VPP vhostuser and tapv2 interfaces. All tests cases use iPerf3 client and server applications running TCP/IP as a traffic generator. For performance comparison the same tests are run without GSO enabled.

GSO Test Topologies

Two VPP GSO test topologies are implemented in CSIT-2106:

  1. iPerfC_GSOvirtio_LinuxVM — GSOvhost_VPP_GSOvhost — iPerfS_GSOvirtio_LinuxVM

    • Tests VPP GSO on vhostuser interfaces and interaction with Linux virtio with GSO enabled.

  1. iPerfC_GSOtap_LinuxNspace — GSOtapv2_VPP_GSOtapv2 — iPerfS_GSOtap_LinuxNspace

    • Tests VPP GSO on tapv2 interfaces and interaction with Linux tap with GSO enabled.

Common configuration:

  • iPerfC (client) and iPerfS (server) run in TCP/IP mode without upper bandwidth limit.

  • Trial duration is set to 30 sec.

  • iPerfC, iPerfS and VPP run in the single SUT node.

VPP GSOtap Topology

VPP Configuration

VPP GSOtap tests in CSIT-2106 are executed without using hyperthreading. VPP worker runs on a single core. Multi-core tests are not executed. Each interface belongs to separate namespace. Following core pinning scheme is used:

  • 1t1c (rxq=1, rx_qsz=4096, tx_qsz=4096)

    • system isolated: 0,28,56,84

    • vpp mt: 1

    • vpp wt: 2

    • vhost: 3-5

    • iperf-s: 6

    • iperf-c: 7

iPerf3 Server Configuration

iPerf3 version used 3.7

$ sudo -E -S ip netns exec tap1_namespace iperf3 \
    --server --daemon --pidfile /tmp/iperf3_server.pid --logfile /tmp/iperf3.log --port 5201 --affinity <X>

For the full iPerf3 reference please see: iPerf3 docs.

iPerf3 Client Configuration

iPerf3 version used 3.7

$ sudo -E -S ip netns exec tap1_namespace iperf3 \
    --client 2.2.2.2 --bind 1.1.1.1 --port 5201 --parallel <Y> --time 30.0 --affinity <X> --zerocopy

For the full iPerf3 reference please see: iPerf3 docs.

VPP GSOvhost Topology

VPP Configuration

VPP GSOvhost tests in CSIT-2106 are executed without using hyperthreading. VPP worker runs on a single core. Multi-core tests are not executed. Following core pinning scheme is used:

  • 1t1c (rxq=1, rx_qsz=1024, tx_qsz=1024) - system isolated: 0,28,56,84 - vpp mt: 1 - vpp wt: 2 - vm-iperf-s: 3,4,5,6,7 - vm-iperf-c: 8,9,10,11,12 - iperf-s: 1 - iperf-c: 1

iPerf3 Server Configuration

iPerf3 version used 3.7

$ sudo iperf3 \
    --server --daemon --pidfile /tmp/iperf3_server.pid --logfile /tmp/iperf3.log --port 5201 --affinity X

For the full iPerf3 reference please see: iPerf3 docs.

iPerf3 Client Configuration

iPerf3 version used 3.7

$ sudo iperf3 \
    --client 2.2.2.2 --bind 1.1.1.1 --port 5201 --parallel <Y> --time 30.0 --affinity X --zerocopy

For the full iPerf3 reference please see: iPerf3 docs.