The Role of Performance Management (PM)

Each IBA device is required to implement a PMA and a minimum set of performance monitoring and error monitoring registers (implemented as PM class attributes). In addition, the specification also defines a set of optional attributes (i.e., registers) permitting the monitoring of additional performance and error counters.

The PM is tasked with retrieving performance and error-related information from these registers. It does this by issuing PM GMP request MADs to a device's PMA. The PMA executes the method on the attribute and, in most cases, returns a result to the PM.

The PM can detect incipient failures (i.e., repetitive soft failures that may become hard failures) and can perform performance analysis. Based on this information, the PM can advise the SM regarding recommended or required path changes (due to errors or poor performance) as well as various load tuning actions that may need to be taken.