https://arxiv.org/abs/2603.04782 Skip to main content Cornell University We gratefully acknowledge support from the Simons Foundation, member institutions, and all contributors. Donate arxiv logo > cs > arXiv:2603.04782 [ ] Help | Advanced Search [All fields ] Search arXiv logo Cornell University Logo [ ] GO quick links * Login * Help Pages * About Computer Science > Distributed, Parallel, and Cluster Computing arXiv:2603.04782 (cs) [Submitted on 5 Mar 2026] Title:Unlocking Python's Cores: Hardware Usage and Energy Implications of Removing the GIL Authors:Jose Daniel Montoya Salazar View a PDF of the paper titled Unlocking Python's Cores: Hardware Usage and Energy Implications of Removing the GIL, by Jos\'e Daniel Montoya Salazar View PDF HTML (experimental) Abstract:Python's Global Interpreter Lock prevents execution on more than one CPU core at the same time, even when multiple threads are used. However, starting with Python 3.13 an experimental build allows disabling the GIL. While prior work has examined speedup implications of this disabling, the effects on energy consumption and hardware utilization have received less attention. This study measures execution time, CPU utilization, memory usage, and energy consumption using four workload categories: NumPy-based, sequential kernels, threaded numerical workloads, and threaded object workloads, comparing GIL and free-threaded builds of Python 3.14.2. The results highlight a trade-off. For parallelizable workloads operating on independent data, the free-threaded build reduces execution time by up to 4 times, with a proportional reduction in energy consumption, and effective multi-core utilization, at the cost of an increase in memory usage. In contrast, sequential workloads do not benefit from removing the GIL and instead show a 13-43% increase in energy consumption. Similarly, workloads where threads frequently access and modify the same objects show reduced improvements or even degradation due to lock contention. Across all workloads, energy consumption is proportional to execution time, indicating that disabling the GIL does not significantly affect power consumption, even when CPU utilization increases. When it comes to memory, the no-GIL build shows a general increase, more visible in virtual memory than in physical memory. This increase is primarily attributed to per-object locking, additional thread-safety mechanisms in the runtime, and the adoption of a new memory allocator. These findings suggest that Python's no-GIL build is not a universal improvement. Developers should evaluate whether their workload can effectively benefit from parallel execution before adoption. Subjects: Distributed, Parallel, and Cluster Computing (cs.DC); Performance (cs.PF) ACM classes: D.3.4; D.3.3; C.4 Cite as: arXiv:2603.04782 [cs.DC] (or arXiv:2603.04782v1 [cs.DC] for this version) https://doi.org/10.48550/arXiv.2603.04782 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Jose Montoya [view email] [v1] Thu, 5 Mar 2026 04:01:30 UTC (166 KB) Full-text links: Access Paper: View a PDF of the paper titled Unlocking Python's Cores: Hardware Usage and Energy Implications of Removing the GIL, by Jos\'e Daniel Montoya Salazar * View PDF * HTML (experimental) * TeX Source view license Current browse context: cs.DC < prev | next > new | recent | 2026-03 Change to browse by: cs cs.PF References & Citations * NASA ADS * Google Scholar * Semantic Scholar export BibTeX citation Loading... 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