TPF Toolkit Performance Analyzer calculation of CPU time
Maria Smith 110000BE9T Visits (809)
The PA is used to provide a profile of where time is being spent in a given application. The PA works by a set of hooks in the TPF system. Basically, these hooks detect Shared Object (CSO & BSO) switching events, ENTxC macros and C/C++ function entry/return events. As an application is being traced, these entry/return events are detected and upon each event, a location and timestamp and stored. Typically, an entry event has a corresponding return event. It's the time in between corresponding entry and return events that the PA reports.
Whether records are found in VFA or on disk the PA is not relevant to the PA. It's only the UAP7_BSO entry and return events that matter to the PA. What happens in between those events, the PA is blind to. Time spent in the CP (CCVFAC) is merely time spent in between the UAP7_BSO entry and return events. And these events occur regardless of where records are found.