Semaphore question in the fork join

SystemVerilog
,
1

I have below code with semaphore. I would like to know how does the semaphore work here ? who will get the semaphore every time ?


semaphore my_sem;
my_sem = new(1);

fork
    forever begin
        my_sem.get();
        my_process1();     // Let's say this process will take 10 cycles to complete
        my_sem.put();
    end
    forever begin
        my_sem.get();
        my_process2();      // Let's say this process will ALSO take 10 cycles to complete
        my_sem.put();
    end
join
2

In reply to zz8318:

Semaphore requests are taken in FIFO order, so the two processes will alternate. Which process gets the first request is a race condition. Once version of a tool might always pick the first or second process, but you should not spend on it.

3

In reply to dave_59:

Hi Dave,

Do you mean the which process picked up at the first time is kind of race-condition. But if it’s determined, then it will select alternately afterwards ? ( like round-robin ?)

4

In reply to zz8318:

Yes, the first time is a race-condition. After that it will be round-robin.

5

In reply to dave_59:

Hi Dave,
You mentioned that the first time is a race-condition. After that it will be round-robin.
Since statements run parallelly in fork join.
Is it possible that two processes will be picked up randomly like this (T0:my_process1 , T1:my_process1,T2:my_process1,T3:my_process0…)?
Thank you