The operating system's trace facility is a powerful system-observation tool. The trace facility captures a sequential flow of time-stamped system events, providing a fine level of detail on system activity. Events are shown in time sequence and in the context of other events. Trace is a valuable tool for observing system and application execution. Unlike other tools that only provide CPU utilization or I/O wait time, trace expands that information to aid in understanding what events are happening, who is responsible, when the events are taking place, how they are affecting the system and why.
The operating system is instrumented to provide general visibility to system execution. Users can extend visibility into their applications by inserting additional events and providing formatting rules.
Care was taken in the design and implementation of this facility to make the collection of trace data efficient, so that system performance and flow would be minimally altered by activating trace. Because of this, the trace facility is extremely useful as a performance-analysis tool and as a problem-determination tool.
The following sections provide more information on the trace facility: