Latency Benchmarks
==================

Latency measurements are provided on the following environment:

- `Xeon`_ -- End-to-end latency measured with the
  |rti_rtiperftest|_ tool on high-performance Xeon machines in 
  a dedicated network .

Xeon
----

The end-to-end latency is measured between two identical machines, using the test
configuration below and running the |rti_rtiperftest|_ tool. 

The test environment consists of the following:

- x86_64 CentOS Linux release 7.1.1503 
- RTI Perftest 3.0
- Switch Configuration: D-Link DXS-3350 SR:

  - 176Gbps Switching Capacity
  - Dual 10-Gig stacking ports and optional 10-Gig uplinks
  - Stacks up to 8 units per stack
  - 4MB (Packet Buffer Size)
  - 48 x 10/100/1000BASE-T ports
  
- Machine:

  - Intel I350 Gigabit NIC
  - Intel Core i7 CPU:
  
    - 12MB cache
    - 6 Cores (12 threads)
    - 3.33 GHz CPU speed
    
  - 12GB memory

The latency is measured by sending one *PING* sample and wait for the Echoer to
return the *PONG* sample. The sender records the time it took to receive
the *PONG* sample and divides the result by 2. The test is repeated a number of 
times for each size. Note that the *end-to-end* latency is measured.

The following measurements are reported in the tables below:

- **Bytes** - The size of the DDS sample payload in bytes (UDP overhead is *not* 
  included).
- **Ave** - Average latency
- **Std** - Standard deviation
- **Min** - The minimum latency
- **Max** - The maximum latency
- **50%** - The 50th percentile latency
- **90%** - The 90th percentile latency
- **99%** - The 99th percentile latency
- **99.99%** - The 99.99th percentile latency

All values are reported in micro-seconds **(µs)**.

C++ Best Effort keyed 1 Gbps
````````````````````````````

.. csv-table:: C++ Best Effort keyed 1 Gbps
   :file: latency/udpv4_cpp_be_keyed_1gb.csv
   :widths: 10, 10, 10, 10, 10, 10, 10, 10, 10
   :header-rows: 1

C++ Best Effort Unkeyed 1 Gbps
``````````````````````````````

.. csv-table:: C++ Best Effort Unkeyed 1 Gbps
   :file: latency/udpv4_cpp_be_unkeyed_1gb.csv
   :widths: 10, 10, 10, 10, 10, 10, 10, 10, 10
   :header-rows: 1


C++ Reliable Keyed 1 Gbps
`````````````````````````

.. csv-table:: C++ Reliable Keyed 1 Gbps
   :file: latency/udpv4_cpp_rel_keyed_1gb.csv
   :widths: 10, 10, 10, 10, 10, 10, 10, 10, 10
   :header-rows: 1


C++ Reliable Unkeyed 1 Gbps
```````````````````````````

.. csv-table:: C++ Reliable Unkeyed 1 Gbps
   :file: latency/udpv4_cpp_rel_unkeyed_1gb.csv
   :widths: 10, 10, 10, 10, 10, 10, 10, 10, 10
   :header-rows: 1