Heads up: if CPython is JIT faster, it may then be (even more) vulnerable to branch prediction vulns like Spectre and Meltdown: https://groups.google.com/g/dev-python/c/67Et2KtpzG4
There's not a PEP for this work either, and one will need to be rebased first, and are there even merge collisions? On Thu, Feb 23, 2023, 9:00 PM Kevin Modzelewski <kev...@gmail.com> wrote: > Ah ok thanks for the tip, I re-posted this as > https://discuss.python.org/t/contributing-the-pyston-jit/24195 > > On Thu, Feb 23, 2023 at 6:02 PM Brett Cannon <br...@python.org> wrote: > >> FYI you will probably get more engagement if you posted this to >> discuss.python.org . >> >> On Thu, Feb 23, 2023, 10:18 Kevin Modzelewski <kev...@gmail.com> wrote: >> >>> Hello all, we on the Pyston team would like to propose the contribution >>> of our JIT >>> <https://github.com/pyston/pyston/blob/pyston_main/Python/aot_ceval_jit.c> >>> into >>> CPython main. We're interested in some initial feedback on this idea before >>> putting in the work to rebase the jit to 3.12 for a PEP and more formal >>> discussion. >>> >>> Our jit is designed to be simple and to generate code quickly, so we >>> believe it's a good point on the design tradeoff curve for potential >>> inclusion. The runtime behavior is intentionally kept almost completely the >>> same as the interpreter, just lowered to machine code and with >>> optimizations applied. >>> >>> Our jit currently targets Python 3.7-3.10, and on 3.8 it achieves a 10% >>> speedup on macrobenchmarks (similar to 3.11). It's hard to estimate the >>> potential speedup of our jit rebased onto 3.12 because there is overlap >>> between what our jit does and the optimizations that have gone into the >>> interpreter since 3.8, but there are several optimizations that would be >>> additive with the current performance work: >>> - Eliminating bytecode dispatch overhead >>> - Mostly-eliminating stack management overhead >>> - Reducing the number of reference count operations in the interpreter >>> - Faster function calls, particularly of C functions >>> - More specialization opportunities, both because a jit is not limited >>> by bytecode limits, but also because it is able to do dynamic >>> specializations that are not possible in an interpreter context >>> >>> There is also room for more optimizations -- in Pyston we've >>> co-optimized the interpreter+jit combination such as by doing more >>> extensive profiling in the interpreter. Our plan would be to submit an >>> initial version that does not contain these optimizations in order to >>> minimize the diff, and add them later. >>> >>> Our jit uses the DynASM assembler library (part of LuaJIT) to generate >>> machine code. Our jit currently supports Mac and Linux, 64-bit ARM and >>> x86_64. Now that we have two architectures supported, adding additional >>> ones is not too much work. >>> >>> We think that our jit fits nicely in the technical roadmap of the Faster >>> CPython project, but conflicts with their plan to build a new custom >>> tracing jit. >>> >>> >>> As mentioned, we'd love to get feedback about the overall appetite for >>> including a jit in CPython! >>> >>> kmod >>> _______________________________________________ >>> Python-Dev mailing list -- python-dev@python.org >>> To unsubscribe send an email to python-dev-le...@python.org >>> https://mail.python.org/mailman3/lists/python-dev.python.org/ >>> Message archived at >>> https://mail.python.org/archives/list/python-dev@python.org/message/7HTSM36GBTP4H5HEUV4JMCDSVYVFFGGV/ >>> Code of Conduct: http://python.org/psf/codeofconduct/ >>> >> _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/TUTSBGG7D7HW6MFHVX46IQDWAF3MJJLS/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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