A trace is visualized as a timeline containing events, all of which are placed on a horizontal track.
A track combines events of the same context. A context can be a single execution thread or a single CPU core.
A track mainly contains two types of events:
- Slices: represent nested and time-limited operations. For example, slices can cover the time period of a function execution, the time spent loading a file from the network, or the time to complete a user journey.
- Counters: represent snapshots of numeric values that change over time. For example, counters can record the instantaneous memory usage of a process during its execution.
System identifiers (such as PIDs, TGIDs, or TIDs) for threads and processes can be reused by the operating system over the course of a trace. This means that they cannot be used as unique identifiers. To solve this problem, Graphics Profiler uses the UTID (unique TID) for threads and UPID (unique PID) for processes.