# CPU pinning

You can pin the child processes of `mpire.WorkerPool` to specific CPUs by using the `cpu_ids` parameter in the constructor:

    # Pin the two child processes to CPUs 2 and 3
    with WorkerPool(n_jobs=2, cpu_ids=[2, 3]) as pool:
        ...

    # Pin the child processes to CPUs 40-59
    with WorkerPool(n_jobs=20, cpu_ids=list(range(40, 60))) as pool:
        ...

    # All child processes have to share a single core:
    with WorkerPool(n_jobs=4, cpu_ids=[0]) as pool:
        ...

    # All child processes have to share multiple cores, namely 4-7:
    with WorkerPool(n_jobs=4, cpu_ids=[[4, 5, 6, 7]]) as pool:
        ...

    # Each child process can use two distinctive cores:
    with WorkerPool(n_jobs=4, cpu_ids=[[0, 1], [2, 3], [4, 5], [6, 7]]) as pool:
        ...

CPU IDs have to be positive integers, not exceeding the number of CPUs available (which can be retrieved by using `mpire.cpu_count()`). Use `None` to disable CPU pinning (which is the default).

Note

Pinning processes to CPU IDs doesn’t work when using threading or when you’re on macOS.