Shedular/Thread issue

Development archive
1

Hi Guys,

I am having a problem with the test code below. Only one thread seems to run even though I give a thread_yield() to it periodically … even the loop in main is ignored.

Is there some issue with the shedular I am not aware of? I thought that the LED thread would get some action? Especially as it has higher priority than the pulser thread.

Cheers,

Bernie

2

Hello Bernard,

our thread priorities are "reversed". The lowest number has the highest priority. PRIORITY_MAIN is medium priority, 0 is the highest priority level, and PRIORITY_IDLE-1 is the least priority.

I hope this helps,

3

Hi Reme,

I understand that. That is why the LED thread has the highest priority (-3) and the Pulser thread the lowest …

Still don’t understand why it does not work.

Bernie

4

Hi Bernie,

Try creating the first thread with the CREATE_WOUT_YIELD flag.

It's too early for me to decide whether this indicates an issue with the scheduler.

Cheers, Ludwig

5

Hi Bernie,

I am having a problem with the test code below. Only one thread seems to run even though I give a thread_yield() to it periodically .. even the loop in main is ignored.

Is there some issue with the shedular I am not aware of? I thought that the LED thread would get some action? Especially as it has higher priority than the pulser thread.

if I don't miss anything I would say, everything's okay.

The main thread starts the pulser thread which immediately takes over (higher priority, not create with CREATE_WOUT_YIELD). Thread pulser runs and yields. Now the scheduler checks which thread is ready to run and has the highest priority -> since led hasn't been created and main has a lower priority, pulser is scheduled again. And so on.

As Ludwig suggested, you probably want to create pulser with the CREATE_WOUT_YIELD flag. If you want a thread to yield and removed from the run queue, you'll have to use thread_sleep().

Cheers, Oleg

6

Ho Oleg,

I am still totally confused! I did as you stated, but my “pulser” thread is not entered … the LED thread runs flashing the LED. code below …

I am about to give up!

Bernie.

7

Hi Bernie,

To combine the flags, you need to use the logic operator |.

Cheers, Ludwig

8

Actually Ludwig, it does not matter if you use “|” or “+” it achieve the same thing …

Bernie

9

I tried your example application yesterday and it worked for me, I only changed this one thing.

Cheers.

10

Hi Bernie!

I am still totally confused! I did as you stated, but my "pulser" thread is not entered ... the LED thread runs flashing the LED. code below ..

I am about to give up!

Don't give up! It's not that complicated and once you've figured out how the scheduler works, it's quite easy to work with.

I guess my explanation was a little bit confusing. I meant that you should only add the CREATE_WOUT_YIELD flag to thread_create() - _not_ additionally replace thread_yield() with thread_sleep().

If you use thread_sleep() you'll also have to wake the thread up somewhere.

So, as Ludwig stated: just adding CREATE_WOUT_YIELD should be fine. (Works as expected in native.)

Cheers, Oleg