The time series plots at http://www.rtems.org/ftp/pub/rtems/people/joel/coverage/erc32.html and for each BSP are simple static plots produced by GNUPlot.  They are generated by the script generate_coverage_html from the RTEMS CVS module rtems-testing in the rtems-coverage CVS directory.  CVS checkout instructions are linked to from www.rtems.org.

Use timeplot (http://www.simile-widgets.org/timeplot/) to implement an alternative to the gnuplot generate time-series graphs. We think you could do two timeline plots which capture the information our 8 png's have.  This would be in addition to the pngs.  It may be too dense so be open to not putting it all on one graph.

Make it pretty and understandable.  Convey information.