Below is a frozen screen shot of the NetLogger life-line graph produced by a sample run in which approximately 100 small files were transferred from lexus.physics.indiana.edu to fndapq.fnal.gov.
Both the engine logic (main thread) and the transfers (individual ftp-threads -- the maximum concurrency was set to 10) are registered. The usefulness of the graphic representation is immediately apparent, in that it highlights how the engine sleep-time (set at 15 seconds) is much too long for the size of the files involved.
Two other kinds of plotting aside from the life-line shown here are available (consult the NetLogger Visualization home page.)
It is also possible to color-code events; however, we have found that once the number of separate colors necessary to represent independent events reaches about 25 (here it would be nearly 100), the visualization tool crashes when trying to display them; hence we have left all threads in monocolor.
NetLogger at FNAL.