What should I consider when testing RTI Connext performance on Gig-E/Infiniband networks?

Performance is a function of how well hardware and software components work together with the middleware. The relationship is certainly not easily predictable. With very fast hardware, the limitation seems to be the hardware bus speed. The PCI just cannot keep up and this leads to high CPU utilization. PCI-Express bus technology seems to fully load a fast transport (like Gig-E) and still keep CPU load reasonable. However, here are some points to consider: 

1. Fabric technologies can be slower than Ethernet IP with certain packet sizes. With small packets, the latency of establishing the connection can become significant.
2. To fully characterize the transport/OS/hardware behavior, we recommend running raw (socket level) tests. Using only RTI Connext/Java/TAO to build your tests can lead to some incorrect assumptions, since these layers can mask some failure modes and limitations.
3. On Gig-E, configuring socket options such as the receive buffer makes a huge difference in throughput tests.

For help with performance testing, please feel free to contact support@rti.com. Latency and throughput test applications are available.