derived values in darshan-parser --perf should be easier to use
The output of darshan-parser --perf is valuable, but there are some problems:
- it still emits several deprecated estimate methods for I/O performance
- it does not emit a unified elapsed time for data and metadata; you can only get this by working backwards from the total_bytes and agg_perf_by_slowest
At some point we should do another usability pass over the output of this tool.