- 0 (=off) disables all output
- 1 (=on) enables only one final message about generating the result
- 2 enables general progress reports by the main process
- 3 enables detailed progress reports by the main process
- 4 the same, but for all processes (if multiple processes are used at all)
- Levels larger than 2 may contain output that only makes sense to the developers of the Intel Trace Collector.