def summarize_reduced_diffs(reduced_diffs):
    """
    Print a human-readable summary of the relevant reduced diff data
    """
    buf = ""
    ### General summary
    if 'sum_data_units_read_gibs' not in reduced_diffs:
        read_gibs = reduced_diffs.get('sum_data_units_read_bytes', 0) * 2.0**(-40)
        write_gibs = reduced_diffs.get('sum_data_units_written_bytes', 0) * 2.0**(-40)
    else:
        read_gibs = reduced_diffs.get('sum_data_units_read_gibs', 0)
        write_gibs = reduced_diffs.get('sum_data_units_written_gibs', 0)

    buf += "Read:    %10.2f TiB, %10.2f MOps\n" % (
        read_gibs,
        reduced_diffs.get('sum_host_read_commands', 0) / 1000000.0)
    buf += "Written: %10.2f TiB, %10.2f MOps\n" % (
        write_gibs,
        reduced_diffs.get('sum_host_write_commands', 0) / 1000000.0)
    buf += "WAF:     %+10.4f\n" % reduced_diffs.get('max_write_amplification_factor', 0)
    return buf