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Python: Difference between revisions
→Multithreading
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from concurrent.futures import ThreadPoolExecutor | from concurrent.futures import ThreadPoolExecutor | ||
executor = ThreadPoolExecutor(max_workers= | executor = ThreadPoolExecutor(max_workers=os.cpu_count()) | ||
thread_lock = threading.Lock() | thread_lock = threading.Lock() | ||
total = 0 | total = 0 | ||
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* <code>len(os.sched_getaffinity(0))</code> returns the number of threads available to the Python process. | * <code>len(os.sched_getaffinity(0))</code> returns the number of threads available to the Python process. | ||
* Starting in Python 3.5, if <code>max_workers</code> is none, it defaults to <code>5 * os.cpu_count()</code>. | * Starting in Python 3.5, if <code>max_workers</code> is none, it defaults to <code>5 * os.cpu_count()</code>. | ||
** <code>os.cpu_count()</code> returns the number of logical CPUs (i.e. threads) | |||
* <code>executor.shutdown()</code> will wait for all jobs to finish but you cannot submit any additional jobs from other threads, after calling shutdown. | * <code>executor.shutdown()</code> will wait for all jobs to finish but you cannot submit any additional jobs from other threads, after calling shutdown. | ||
* List operations are thread-safe but most other operations will require using a thread lock or semaphore. | * List operations are thread-safe but most other operations will require using a thread lock or semaphore. | ||