[qsort]

> can you explain how generators work with multiprocess

The best way to think of a generator is as an object implementing the iteration protocol. They don't really interact with concurrency, as far as multiprocess is concerned, they're just regular objects. So the answer is that it depends on how you plan to share memory between the processes.

> is ps internal variable unique for each Thread or same?

ps is local to the generator instance.

  def f():
      x = 0
      while True:
          yield (x := x + 1)
 
  >>> f()
  <generator object f at 0x10412e500>
  >>> x = f()
  >>> y = f()
  >>> next(x)
  1
  >>> next(x)
  2
  >>> next(y)
  1

> is it safe to execute your primes() from different threads?

For this specific generator, you would run into the GIL. More generally, if you're talking about non CPU-bound operations, you need to synchronize the threads. It's worth looking into asyncio for those use cases.