Concurrent Execution ¶

The modules described in this chapter provide support for concurrent execution of code. The appropriate choice of tool will depend on the task to be executed (CPU bound vs IO bound) and preferred style of development (event driven cooperative multitasking vs preemptive multitasking). Here’s an overview:


      
       threading

— Thread-based parallelism

Thread-Local Data
Thread Objects
Lock Objects
RLock Objects
Condition Objects
Semaphore Objects
- Semaphore Example
- Event Objects
- Timer Objects
- Barrier Objects
- Using locks, conditions, and semaphores in the with statement
- multiprocessing — Process-based parallelism
  - Introduction
    - The Process class
    - Contexts and start methods
    - Exchanging objects between processes
    - Synchronization between processes
    - Sharing state between processes
    - Using a pool of workers
    - Reference
      - Process and exceptions
      - Pipes and Queues
      - Miscellaneous
      - Connection Objects
      - Synchronization primitives
      - Shared ctypes Objects
        
        The multiprocessing.sharedctypes module
        
        Managers
        
        Customized managers
        
        Using a remote manager
        
        Proxy Objects
        
        Cleanup
        
        Process Pools
        
        Listeners and Clients
        
        Address Formats
        
        Authentication keys
        
        Logging
        
        The multiprocessing.dummy module
        
        Programming guidelines
        
        All start methods
        
        The spawn and forkserver start methods
        
        Examples
        
        multiprocessing.shared_memory — Shared memory for direct access across processes
        
        The concurrent package
        
        concurrent.futures — Launching parallel tasks
        
        Executor Objects
        
        ThreadPoolExecutor
        
        ThreadPoolExecutor Example
        
        ProcessPoolExecutor
        
        ProcessPoolExecutor Example
        
        Future Objects
        
        Module Functions
        
        Exception classes
        
        subprocess — Subprocess management
        
        Using the subprocess Module
        
        Frequently Used Arguments
        
        Popen Constructor
        
        Exceptions
        
        Security Considerations
        
        Popen Objects
        
        Windows Popen Helpers
        
        Windows Constants
        
        Older high-level API
        
        Replacing Older Functions with the subprocess Module
        
        Replacing /bin/sh shell command substitution
        
        Replacing shell pipeline
        
        Replacing os.system()
        
        Replacing the os.spawn family
        
        Replacing os.popen() , os.popen2() , os.popen3()
        
        Replacing functions from the popen2 module
        
        Legacy Shell Invocation Functions
        
        Notes
        
        Converting an argument sequence to a string on Windows
        
        Disabling use of vfork() or posix_spawn()
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