Overview

InfiniBand architecture provides the technology for an application on one node to transport data to and from an application on another node. Furthermore, the data transport can be a message or the application exchanging data directly between its memory and memory in another node.

How does an application utilize the architecture and its benefits? Applications fall into two categories, general applications and special applications.

A general application is an application that loads and executes without-any special considerations or privileges.

A special application is an application that requires special attention from the operating system (e.g., access to a special Queue Pair (QP), special privileges such as a privileged Q_Key or use of a special P_Key, etc.). Some examples of special applications are Subnet Manager, GSA, GSM, legacy communication stack, etc. In many cases, special applications function the same as general applications with respect to gaining access to InfiniBand service.

The previous chapters define a reference service model, which answers the questions of: what functionality the operating system should expose to an application. This chapter explains how an application can take advantage of that functionality.

Applications, regardless of whether they are user level applications or kernel level agents, are the real clients of the architecture. Providing applications with new capabilities and advantages not available in existing technologies was the prime motivation in developing the InfiniBand technology. The key word is new, and to take advantage of new concepts requires a new perspective.

Two viewpoints are important to this new perspective:

• One...