path: root/docs/report/vpp_performance_tests/overview.rst

Overview
========

Tested Physical Topologies
--------------------------

CSIT VPP performance tests are executed on physical baremetal servers hosted by
:abbr:`LF (Linux Foundation)` 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:

#. 2port10GE X520-DA2 Intel.
#. 2port10GE X710 Intel.
#. 2port10GE VIC1227 Cisco.
#. 2port40GE VIC1385 Cisco.
#. 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 :abbr:`LF (Linux Foundation)` 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 :abbr:`LF (Linux Foundation)` FD.io test bed specification and
physical topology please refer to `LF FD.io CSIT testbed wiki page
<https://wiki.fd.io/view/CSIT/CSIT_LF_testbed>`_.

Performance Tests Coverage
--------------------------

Performance tests are split into two main categories:

- Throughput discovery - discovery of packet forwarding rate using binary search
  in accordance to :rfc:`2544`.

  - 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 |release| 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 :abbr:`LF (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.

Performance Tests Naming
------------------------

CSIT |release| follows a common structured naming convention for all performance
and system functional tests, introduced in CSIT |release-1|.

The naming should be intuitive for majority of the tests. Complete description
of CSIT test naming convention is provided on `CSIT test naming wiki
<https://wiki.fd.io/view/CSIT/csit-test-naming>`_.

Methodology: Multi-Core and Multi-Threading
-------------------------------------------

**Intel Hyper-Threading** - CSIT |release| 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 |release| multi-core tests are executed in the
following VPP thread and core configurations:

#. 1t1c - 1 VPP worker thread on 1 CPU physical core.
#. 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.

Methodology: Packet Throughput
------------------------------

Following values are measured and reported for packet throughput tests:

- NDR binary search per :rfc:`2544`:

  - 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 :rfc:`2544`:

  - 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.

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.


Methodology: KVM VM vhost
-------------------------

CSIT |release| introduced test environment configuration changes to KVM Qemu
vhost-user tests in order to more representatively measure |vpp-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 :abbr:`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 :abbr:`CFS (Completely Fair Scheduler)` scheduler policy
  for data plane threads used in CSIT is documented in
  `CSIT Performance Environment Tuning wiki <https://wiki.fd.io/view/CSIT/csit-perf-env-tuning-ubuntu1604>`_.
  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.

Methodology: LXC Container memif
--------------------------------

CSIT |release| 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 :abbr:`LXC (Linux Container)` 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.

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 |release| 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.

Methodology: TRex Traffic Generator Usage
-----------------------------------------

The `TRex traffic generator <https://wiki.fd.io/view/TRex>`_ 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
  :command:`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.