[LITMUS^RT] DEMO plugin problems

[Björn Brandenburg]

On 16. Jul 2017, at 11:04, Matteo Locatelli <matteo.locatelli1993 at gmail.com> wrote:
> using the recently updated guide for the creation of a new Litmus plugin, I created the DEMO plugin which works correctly except for two things:
> 1 - when I try to use the release_ts functionality, an error appears saying "wait_for_ts_release(): Function not implemented”

That’s strange. Are you sure this happens only with the demo plugin? Is liblitmus up-to-date? I don’t immediately see a reason why this should fail with the DEMO plugin.

Nathan, did you happen to see anything like this? Can you reproduce this?

> 2 - when I use the st-trace-schedule functionality and run some processes using rtspin, the amount of bytes written to the traces are smaller then usual (72 bytes with the DEMO plugin, approximately 4000 bytes with the PSN-EDF scheduler)

Did the tasks actually run? Most of the tracing happens in core LITMUS^RT code (i.e., it’s independent of the plugin), so I don’t think this difference is due to tracing differences in the plugins. 

> and if I try to draw the schedule using the st-draw functionality, it gives this error:
> 
> Traceback (most recent call last):
>   File "/opt/feather-trace-tools/st-draw", line 146, in <module>
>     main()
>   File "/opt/feather-trace-tools/st-draw", line 136, in main
>     sched_trace.draw.render(opts, trace)
>   File "/opt/feather-trace-tools/sched_trace/draw.py", line 282, in render
>     y   = ypos(task_idx[pid] + 1)
> KeyError: 2741

The plotting script still is pretty much beta, so it doesn’t handle unexpected data very gracefully. If you send me your traces I can take a look. Of course, you could try to debug this yourself and send a patch, which would also be very much appreciated. ;-)

- Björn