"The best way to invoke latencytop is by passing no command-line
options. LatencyTOP will then start with a curses interface and
continually update the display with information about what process
has the greatest latency on your system. If you pass the -d option,
LatencyTOP will print the current top latencies and exit. If you
pass --block, the program will print some debug-level messages
about block IO.: