2.1. Overview

2.1.1. Tested Physical Topologies

CSIT VPP performance tests are executed on physical baremetal servers hosted by LF FD.io project. Testbed physical topology is shown in the figure below.

+------------------------+           +------------------------+
|                        |           |                        |
|  +------------------+  |           |  +------------------+  |
|  |                  |  |           |  |                  |  |
|  |                  <----------------->                  |  |
|  |       DUT1       |  |           |  |       DUT2       |  |
|  +--^---------------+  |           |  +---------------^--+  |
|     |                  |           |                  |     |
|     |            SUT1  |           |  SUT2            |     |
+------------------------+           +------------------^-----+
      |                                                 |
      |                                                 |
      |                  +-----------+                  |
      |                  |           |                  |
      +------------------>    TG     <------------------+
                         |           |
                         +-----------+

SUT1 and SUT2 are two System Under Test servers (Cisco UCS C240, each with two Intel XEON CPUs), TG is a Traffic Generator (TG, another Cisco UCS C240, with two Intel XEON CPUs). SUTs run VPP SW application in Linux user-mode as a Device Under Test (DUT). TG runs TRex SW application as a packet Traffic Generator. Physical connectivity between SUTs and to TG is provided using different NIC models that need to be tested for performance. Currently installed and tested NIC models include:

  1. 2port10GE X520-DA2 Intel.
  2. 2port10GE X710 Intel.
  3. 2port10GE VIC1227 Cisco.
  4. 2port40GE VIC1385 Cisco.
  5. 2port40GE XL710 Intel.

From SUT and DUT perspective, all performance tests involve forwarding packets between two physical Ethernet ports (10GE or 40GE). Due to the number of listed NIC models tested and available PCI slot capacity in SUT servers, in all of the above cases both physical ports are located on the same NIC. In some test cases this results in measured packet throughput being limited not by VPP DUT but by either the physical interface or the NIC capacity.

Going forward CSIT project will be looking to add more hardware into FD.io performance labs to address larger scale multi-interface and multi-NIC performance testing scenarios.

For test cases that require DUT (VPP) to communicate with VirtualMachines(VMs)/LinuxContainers(LXCs) over vhost-user/memif interfaces, N of VM/LXC instances are created on SUT1 and SUT2. For N=1 DUT forwards packets between vhost/memif and physical interfaces. For N>1 DUT a logical service chain forwarding topology is created on DUT by applying L2 or IPv4/IPv6 configuration depending on the test suite. DUT test topology with N VM/LXC instances is shown in the figure below including applicable packet flow thru the DUTs and VMs/LXCs (marked in the figure with ***).

+-------------------------+           +-------------------------+
| +---------+ +---------+ |           | +---------+ +---------+ |
| |VM/LXC[1]| |VM/LXC[N]| |           | |VM/LXC[1]| |VM/LXC[N]| |
| |  *****  | |  *****  | |           | |  *****  | |  *****  | |
| +--^---^--+ +--^---^--+ |           | +--^---^--+ +--^---^--+ |
|   *|   |*     *|   |*   |           |   *|   |*     *|   |*   |
| +--v---v-------v---v--+ |           | +--v---v-------v---v--+ |
| |  *   *       *   *  |*|***********|*|  *   *       *   *  | |
| |  *   *********   ***<-|-----------|->***   *********   *  | |
| |  *    DUT1          | |           | |       DUT2       *  | |
| +--^------------------+ |           | +------------------^--+ |
|   *|                    |           |                    |*   |
|   *|            SUT1    |           |  SUT2              |*   |
+-------------------------+           +-------------------------+
    *|                                                     |*
    *|                                                     |*
    *|                    +-----------+                    |*
    *|                    |           |                    |*
    *+-------------------->    TG     <--------------------+*
    **********************|           |**********************
                          +-----------+

For VM/LXC tests, packets are switched by DUT multiple times: twice for a single VM/LXC, three times for two VMs/LXCs, N+1 times for N VMs/LXCs. Hence the external throughput rates measured by TG and listed in this report must be multiplied by (N+1) to represent the actual DUT aggregate packet forwarding rate.

Note that reported DUT (VPP) performance results are specific to the SUTs tested. Current LF FD.io SUTs are based on Intel XEON E5-2699v3 2.3GHz CPUs. SUTs with other CPUs are likely to yield different results. A good rule of thumb, that can be applied to estimate VPP packet thoughput for Phy-to-Phy (NIC-to-NIC, PCI-to-PCI) topology, is to expect the forwarding performance to be proportional to CPU core frequency, assuming CPU is the only limiting factor and all other SUT parameters equivalent to FD.io CSIT environment. The same rule of thumb can be also applied for Phy-to-VM/LXC-to-Phy (NIC-to-VM/LXC-to-NIC) topology, but due to much higher dependency on intensive memory operations and sensitivity to Linux kernel scheduler settings and behaviour, this estimation may not always yield good enough accuracy.

For detailed LF FD.io test bed specification and physical topology please refer to LF FD.io CSIT testbed wiki page.

2.1.2. Performance Tests Coverage

Performance tests are split into two main categories:

  • Throughput discovery - discovery of packet forwarding rate using binary search in accordance to RFC2544.
    • NDR - discovery of Non Drop Rate packet throughput, at zero packet loss; followed by one-way packet latency measurements at 10%, 50% and 100% of discovered NDR throughput.
    • PDR - discovery of Partial Drop Rate, with specified non-zero packet loss currently set to 0.5%; followed by one-way packet latency measurements at 100% of discovered PDR throughput.
  • Throughput verification - verification of packet forwarding rate against previously discovered throughput rate. These tests are currently done against 0.9 of reference NDR, with reference rates updated periodically.

CSIT rls1707 includes following performance test suites, listed per NIC type:

  • 2port10GE X520-DA2 Intel
    • L2XC - L2 Cross-Connect switched-forwarding of untagged, dot1q, dot1ad VLAN tagged Ethernet frames.
    • L2BD - L2 Bridge-Domain switched-forwarding of untagged Ethernet frames with MAC learning; disabled MAC learning i.e. static MAC tests to be added.
    • IPv4 - IPv4 routed-forwarding.
    • IPv6 - IPv6 routed-forwarding.
    • IPv4 Scale - IPv4 routed-forwarding with 20k, 200k and 2M FIB entries.
    • IPv6 Scale - IPv6 routed-forwarding with 20k, 200k and 2M FIB entries.
    • VMs with vhost-user - virtual topologies with 1 VM and service chains of 2 VMs using vhost-user interfaces, with VPP forwarding modes incl. L2 Cross-Connect, L2 Bridge-Domain, VXLAN with L2BD, IPv4 routed-forwarding.
    • COP - IPv4 and IPv6 routed-forwarding with COP address security.
    • iACL - IPv4 and IPv6 routed-forwarding with iACL address security.
    • LISP - LISP overlay tunneling for IPv4-over-IPv4, IPv6-over-IPv4, IPv6-over-IPv6, IPv4-over-IPv6 in IPv4 and IPv6 routed-forwarding modes.
    • VXLAN - VXLAN overlay tunnelling integration with L2XC and L2BD.
    • QoS Policer - ingress packet rate measuring, marking and limiting (IPv4).
    • CGNAT - Carrier Grade Network Address Translation tests with varying number of users and ports per user.
  • 2port40GE XL710 Intel
    • L2XC - L2 Cross-Connect switched-forwarding of untagged Ethernet frames.
    • L2BD - L2 Bridge-Domain switched-forwarding of untagged Ethernet frames with MAC learning.
    • IPv4 - IPv4 routed-forwarding.
    • IPv6 - IPv6 routed-forwarding.
    • VMs with vhost-user - virtual topologies with 1 VM and service chains of 2 VMs using vhost-user interfaces, with VPP forwarding modes incl. L2 Cross-Connect, L2 Bridge-Domain, VXLAN with L2BD, IPv4 routed-forwarding.
    • IPSec - IPSec encryption with AES-GCM, CBC-SHA1 ciphers, in combination with IPv4 routed-forwarding.
    • IPSec+LISP - IPSec encryption with CBC-SHA1 ciphers, in combination with LISP-GPE overlay tunneling for IPv4-over-IPv4.
  • 2port10GE X710 Intel
    • L2BD - L2 Bridge-Domain switched-forwarding of untagged Ethernet frames with MAC learning.
    • VMs with vhost-user - virtual topologies with 1 VM using vhost-user interfaces, with VPP forwarding modes incl. L2 Bridge-Domain.
  • 2port10GE VIC1227 Cisco
    • L2BD - L2 Bridge-Domain switched-forwarding of untagged Ethernet frames with MAC learning.
  • 2port40GE VIC1385 Cisco
    • L2BD - L2 Bridge-Domain switched-forwarding of untagged Ethernet frames
      with MAC learning.

Execution of performance tests takes time, especially the throughput discovery tests. Due to limited HW testbed resources available within FD.io labs hosted by Linux Foundation, the number of tests for NICs other than X520 (a.k.a. Niantic) has been limited to few baseline tests. CSIT team expect the HW testbed resources to grow over time, so that complete set of performance tests can be regularly and(or) continuously executed against all models of hardware present in FD.io labs.

2.1.3. Performance Tests Naming

CSIT rls1707 follows a common structured naming convention for all performance and system functional tests, introduced in CSIT rls1704.

The naming should be intuitive for majority of the tests. Complete description of CSIT test naming convention is provided on CSIT test naming wiki.

2.1.4. Methodology: Multi-Core and Multi-Threading

Intel Hyper-Threading - CSIT rls1707 performance tests are executed with SUT servers’ Intel XEON processors configured in Intel Hyper-Threading Disabled mode (BIOS setting). This is the simplest configuration used to establish baseline single-thread single-core application packet processing and forwarding performance. Subsequent releases of CSIT will add performance tests with Intel Hyper-Threading Enabled (requires BIOS settings change and hard reboot of server).

Multi-core Tests - CSIT rls1707 multi-core tests are executed in the following VPP thread and core configurations:

  1. 1t1c - 1 VPP worker thread on 1 CPU physical core.
  2. 2t2c - 2 VPP worker threads on 2 CPU physical cores.

VPP worker threads are the data plane threads. VPP control thread is running on a separate non-isolated core together with other Linux processes. Note that in quite a few test cases running VPP workers on 2 physical cores hits the tested NIC I/O bandwidth or packets-per-second limit.

2.1.5. Methodology: Packet Throughput

Following values are measured and reported for packet throughput tests:

  • NDR binary search per RFC2544:
    • Packet rate: “RATE: <aggregate packet rate in packets-per-second> pps (2x <per direction packets-per-second>)”
    • Aggregate bandwidth: “BANDWIDTH: <aggregate bandwidth in Gigabits per second> Gbps (untagged)”
  • PDR binary search per RFC2544:
    • Packet rate: “RATE: <aggregate packet rate in packets-per-second> pps (2x <per direction packets-per-second>)”
    • Aggregate bandwidth: “BANDWIDTH: <aggregate bandwidth in Gigabits per second> Gbps (untagged)”
    • Packet loss tolerance: “LOSS_ACCEPTANCE <accepted percentage of packets lost at PDR rate>”“
  • NDR and PDR are measured for the following L2 frame sizes:
    • IPv4: 64B, IMIX_v4_1 (28x64B,16x570B,4x1518B), 1518B, 9000B.
    • IPv6: 78B, 1518B, 9000B.

All rates are reported from external Traffic Generator perspective.

2.1.6. Methodology: Packet Latency

TRex Traffic Generator (TG) is used for measuring latency of VPP DUTs. Reported latency values are measured using following methodology:

  • Latency tests are performed at 10%, 50% of discovered NDR rate (non drop rate) for each NDR throughput test and packet size (except IMIX).
  • TG sends dedicated latency streams, one per direction, each at the rate of 10kpps at the prescribed packet size; these are sent in addition to the main load streams.
  • TG reports min/avg/max latency values per stream direction, hence two sets of latency values are reported per test case; future release of TRex is expected to report latency percentiles.
  • Reported latency values are aggregate across two SUTs due to three node topology used for all performance tests; for per SUT latency, reported value should be divided by two.
  • 1usec is the measurement accuracy advertised by TRex TG for the setup used in FD.io labs used by CSIT project.
  • TRex setup introduces an always-on error of about 2*2usec per latency flow - additonal Tx/Rx interface latency induced by TRex SW writing and reading packet timestamps on CPU cores without HW acceleration on NICs closer to the interface line.

2.1.7. Methodology: KVM VM vhost

CSIT rls1707 introduced test environment configuration changes to KVM Qemu vhost- user tests in order to more representatively measure VPP-17.07 release performance in configurations with vhost-user interfaces and different Qemu settings.

FD.io CSIT performance lab is testing VPP vhost with KVM VMs using following environment settings

  • Tests with varying Qemu virtio queue (a.k.a. vring) sizes: [vr256] default 256 descriptors, [vr1024] 1024 descriptors to optimize for packet throughput;
  • Tests with varying Linux CFS (Completely Fair Scheduler) settings: [cfs] default settings, [cfsrr1] CFS RoundRobin(1) policy applied to all data plane threads handling test packet path including all VPP worker threads and all Qemu testpmd poll-mode threads;
  • Resulting test cases are all combinations with [vr256,vr1024] and [cfs,cfsrr1] settings;
  • Adjusted Linux kernel CFS scheduler policy for data plane threads used in CSIT is documented in CSIT Performance Environment Tuning wiki. The purpose is to verify performance impact (NDR, PDR throughput) and same test measurements repeatability, by making VPP and VM data plane threads less susceptible to other Linux OS system tasks hijacking CPU cores running those data plane threads.

2.1.8. Methodology: LXC Container memif

CSIT rls1707 introduced new tests - VPP Memif virtual interface (shared memory interface) tests interconnecting VPP instances over memif. VPP vswitch instance runs in bare-metal user-mode handling Intel x520 NIC 10GbE interfaces and connecting over memif (Master side) virtual interfaces to another instance of VPP running in bare-metal Linux Container (LXC) with memif virtual interfaces (Slave side). LXC runs in a priviliged mode with VPP data plane worker threads pinned to dedicated physical CPU cores per usual CSIT practice. Both VPP run the same version of software. This test topology is equivalent to existing tests with vhost-user and VMs.

2.1.9. Methodology: IPSec with Intel QAT HW cards

VPP IPSec performance tests are using DPDK cryptodev device driver in combination with HW cryptodev devices - Intel QAT 8950 50G - present in LF FD.io physical testbeds. DPDK cryptodev can be used for all IPSec data plane functions supported by VPP.

Currently CSIT rls1707 implements following IPSec test cases:

  • AES-GCM, CBC-SHA1 ciphers, in combination with IPv4 routed-forwarding with Intel xl710 NIC.
  • CBC-SHA1 ciphers, in combination with LISP-GPE overlay tunneling for IPv4-over-IPv4 with Intel xl710 NIC.

2.1.10. Methodology: TRex Traffic Generator Usage

The TRex traffic generator is used for all CSIT performance tests. TRex stateless mode is used to measure NDR and PDR throughputs using binary search (NDR and PDR discovery tests) and for quick checks of DUT performance against the reference NDRs (NDR check tests) for specific configuration.

TRex is installed and run on the TG compute node. The typical procedure is:

  • If the TRex is not already installed on TG, it is installed in the suite setup phase - see TRex intallation.

  • TRex configuration is set in its configuration file

    /etc/trex_cfg.yaml
    
  • TRex is started in the background mode

    $ sh -c 'cd /opt/trex-core-2.25/scripts/ && sudo nohup ./t-rex-64 -i -c 7 --iom 0 > /dev/null 2>&1 &' > /dev/null
    
  • There are traffic streams dynamically prepared for each test, based on traffic profiles. The traffic is sent and the statistics obtained using trex_stl_lib.api.STLClient.

Measuring packet loss

  • Create an instance of STLClient
  • Connect to the client
  • Add all streams
  • Clear statistics
  • Send the traffic for defined time
  • Get the statistics

If there is a warm-up phase required, the traffic is sent also before test and the statistics are ignored.

Measuring latency

If measurement of latency is requested, two more packet streams are created (one for each direction) with TRex flow_stats parameter set to STLFlowLatencyStats. In that case, returned statistics will also include min/avg/max latency values.