Report: Placeholder for LD preload tests

- methodology
- test results

Change-Id: I0d102875045ab295d9b44fa7bc328f2a728803d7
Signed-off-by: Tibor Frank <tifrank@cisco.com>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
(cherry picked from commit 107438e93a51eefc61dc171cfa9b959007ccc739)

1 files changed, 41 insertions, 0 deletions

diff --git a/docs/report/introduction/methodology_tcp_with_iperf3.rst b/docs/report/introduction/methodology_tcp_with_iperf3.rst
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+Hoststack Throughput Testing over TCP/IP with iperf3
+----------------------------------------------------
+
+`iperf3 bandwidth measurement tool <https://github.com/esnet/iperf>`_
+is used for measuring the maximum attainable bandwidth of the VPP Host
+Stack connection across two instances of VPP running on separate DUT
+nodes. iperf3 is a popular open source tool for active measurements
+of the maximum achievable bandwidth on IP networks.
+
+Because iperf3 utilizes the POSIX socket interface APIs, the current
+test configuration utilizes the LD_PRELOAD mechanism in the linux
+kernel to connect iperf3 to the VPP Host Stack using the VPP
+Communications Library (VCL) LD_PRELOAD library (libvcl_ldpreload.so).
+
+In the future, a forked version of iperf3 which has been modified to
+directly use the VCL application APIs may be added to determine the
+difference in performance of 'VCL Native' applications .vs. utilizing
+LD_PRELOAD which inherently has more overhead and other limitations.
+
+The test configuration is as follows:
+
+       DUT1              Network               DUT2
+[ iperf3-client -> VPP1 ]=======[ VPP2 -> iperf3-server]
+
+where,
+
+ 1. iperf3 server attaches to VPP2 and LISTENs on VPP2:TCP port 5201.
+ 2. iperf3 client attaches to VPP1 and opens one or more stream
+    connections to VPP2:TCP port 5201.
+ 3. iperf3 client transmits a uni-directional stream as fast as the
+    VPP Host Stack allows to the iperf3 server for the test duration.
+ 4. At the end of the test the iperf3 client emits the goodput
+    measurements for all streams and the sum of all streams.
+
+ Test cases include 1 and 10 Streams with a 20 second test duration
+ with the VPP Host Stack configured to utilize the Cubic TCP
+ congestion algorithm.
+
+ Note: iperf3 is single threaded, so it is expected that the 10 stream
+ test does not show any performance improvement due to
+ multi-thread/multi-core execution.