The Application Response Measurement API (ARM)

The Application Response Measurement API (ARM) [#!C807!#] has been developed in 1996 in a joint initiative of Tivoli Systems and Hewlett-Packard. Later that year HP, Tivoli and 13 more companies established the ARM Working Group of the Computer Measurement Group (CMG) to continue development and promotion of the API. It promises to allow transaction based monitoring of response times in a distributed and heterogeneous environment. Work on version 2.0 of the API was finished in November 1997. In January 1999 the ARM API version 2.0 was adopted by the Open Group as its technical standard for application performance instrumentation.Using the ARM API  [r]

To achieve the goals mentioned above a simple API was defined that is supposed to be implemented by management tools. The applications to be monitored have to be instrumented to call the API whenever a transaction starts or stops. Actual performance monitoring is done by using management tools that provide measurement agents implementing the API. These are linked against the application to be monitored and thus are called whenever a transaction is initiated or ended. (see figure ). An important feature added with version 2.0 of the API is correlation of transactions. Often one transaction visible to the user consists of a number of subtransactions. When indicating the start of a new transaction, a data structure called a correlator can be requested from the measurement agent. When indicating the start of a subtransaction, this correlator can be used to inform the measurement agent about the existence and identity of a parent transaction.