Function warm_up_thread_pool

dask/tests/test_threaded.py:205–219

Ensure that there is a warm thread pool. With num_workers=None on the default thread, this function warms up the default thread pool. With num_workers set or from a different thread, this function spawns and warms up a non-default thread pool. When this function is called after ano

(num_workers: int | None)

def warm_up_thread_pool(num_workers: int | None) -> None:
    """Ensure that there is a warm thread pool.

    With num_workers=None on the default thread, this function warms up the default
    thread pool. With num_workers set or from a different thread, this function spawns
    and warms up a non-default thread pool.

    When this function is called after another test that called get() or compute(), the
    thread pool will be already warm, at least partially (not all threads will
    necessarily be already running).
    """
    parties = num_workers or CPU_COUNT
    barrier = threading.Barrier(parties)
    dsk = {("x", i): (barrier.wait,) for i in range(parties)}
    get(dsk, list(dsk), num_workers=num_workers)


test_ctxvar = contextvars.ContextVar("test_ctxvar", default=42)