[INFO] Tickless mode for ChibiOS/RT 3.0

[Giovanni]

Hi Leon,

It's been a while

Years after first discussing this tickless mode and high resolution timers... it is finally here

Tomorrow it is the release day.

Giovanni

[alex31]

Hello

what about

2) Thread profiling debug option is not functional in tickless mode. It will be reimplemented when the kernel will receive the RT timer handling currently in the HAL.

?

I have found that there is a statistic subsystem, but i have not found examples using it, and it doesn't seems to collect per thread data but
global scheduler data.

So the question is, using current ChibiOS dev branch, is there a mean to get Thread profiling data ?

Thanks
Alexandre

[Giovanni]

No, statistics do it better (much better).

Once activated statistics are accessible via the ChibiOS/RT 4 debug plugin in eclipse, there should be screenshots on the forum somewhere or just try it in ChibiStudio, it is included.

Giovanni

[alex31]

No, statistics do it better (much better).

Once activated statistics are accessible via the ChibiOS/RT 4 debug plugin in eclipse, there should be screenshots on the forum somewhere or just try it in ChibiStudio, it is included.

Ok, looks promising, thanks

In fact, i need to let the program do his own introspection an take decision based on threads load, so i need to be able to
get data from chibios, can one imagine a public api to get this data instead of working with chibios private data ?

Alexandre

[Giovanni]

Hi,

The data can be accessed at runtime using the registry API then accessing the statistics structure in each thread.

If you just need thread load then statistics are overkill probably and would slow down the system, you better disable tickless mode and use profiling. Profiling is just a counter incremented in the current thread when a system tick occurs (this is why it is not compatible with tickless mode).

There is another solution for threads load: use the idle-enter and idle-leave macros together with the realtime counter, you can measure how much time is spent into the idle thread and it is compatible with tickless mode.

Giovanni