Communication using Eve starts with the definition of an artificial event code for use by the communicating EMs. Communicating EMs also agree on the type and meaning of the associated event value. Eve then broadcasts this event to those tools that requested artificial event reports. This section describes the primary techniques employed in Eve to obtain good performance. The key ideas are to filter events at the source and to precompute the set of EMs to which each event code is distributed.
Different EMs require different kinds of events.
After obtaining a list of client EMs to execute, Eve loads each client. Computation of the minimal event set Each time an EM requests its next event report from Eve, it transmits a cset event mask indicating what events it is interested in. Eve could simply request all events from the TP, and forward event reports to each EM based on its current mask. In order to minimize the cost of monitoring, Eve asks the TP for the least set of events required to satisfy the EMs. Although every EM can potentially change its event mask every time it requests an event, constant recomputation of the union mask would be unacceptably expensive.