Quick Answer
The GIL (Global Interpreter Lock) is a mutex in CPython that allows only one thread to execute Python bytecode at a time. This means CPU-bound multi-threaded code doesn't actually run in parallel. I/O-bound threads still benefit (GIL is released during I/O). For CPU-bound parallelism, use multiprocessing (separate processes, no GIL) or C extensions that release the GIL.
Answer
GIL allows only one thread to execute Python bytecode at a time. Limits CPU-bound threading. I/O-bound threads work well. Multiprocessing bypasses GIL.
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SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
