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Re:Python 3.15's interpreter for Windows should be 15% faster by kenjin4096 on Thursday December 25, 2025 @05:53PM (#46387560)
> Generally not that much has happened in 5 years, sometimes 10-15% improvements are posted that are later offset by bloat.

Sorry but unless your workload is some C API numpy number cruncher that just does matmuls on the CPU, that's probably false.

In 3.11 alone, CPython sped up by around 25% over 3.10 on pyperformance for x86-64 Ubuntu. https://docs.python.org/3/whatsnew/3.11.html#whatsnew311-fas...

3.14 is 35-45% faster than CPython 3.10 for pyperformance x86-64 Ubuntu https://github.com/faster-cpython/benchmarking-public

These speedups have been verified by external projects. For example, a Python MLIR compiler that I follow has found a geometric mean 36% speedup moving from CPython 3.10 to 3.11 (page 49 of https://github.com/EdmundGoodman/masters-project-report)

Another academic benchmark here observed an around 1.8x speedup on their benchmark suite for 3.13 vs 3.10 https://youtu.be/03DswsNUBdQ?t=145

CPython 3.11 sped up enough that PyPy in comparison looks slightly slower. I don't know if anyone still remembers this: but back in the CPython 3.9 days, PyPy had over 4x speedup over CPython on the PyPy benchmark suite, now it's 2.8 on their website https://speed.pypy.org/ for 3.11.

Yes CPython is still slow, but it's getting faster :).

Disclaimer: I'm just a volunteer, not an employee of Microsoft, so I don't have a perf report to answer to. This is just my biased opinion.

Re:Python 3.15's interpreter for Windows should be 15% faster by tom_ on Thursday December 25, 2025 @07:49PM (#46388137)
As a data point, running a Python program I've been working on lately, which is near enough entirely Python code, with a bit of I/O: (a prototype for some code I'll ultimately be writing in a lower-level language)

(macOS Ventura, x64)

- System python 3.9.6: 26.80s user 0.27s system 99% cpu 27.285 total

- MacPorts python 3.9.25: 23.83s user 0.32s system 98% cpu 24.396 total

- MacPorts python 3.13.11: 15.17s user 0.28s system 98% cpu 15.675 total

- MacPorts python 3.14.2: 15.31s user 0.32s system 98% cpu 15.893 total

Wish I'd thought to try this test sooner now. (I generally haven't bothered with Python upgrades much, on the basis that the best version will be the one that's easiest to install, or, better yet, is there already. I'm quite used to the language and stdlib as the are, and I've just assumed the performance will still be as limited as it always has been...!)

Re:Python 3.15's interpreter for Windows should be 15% faster by llimllib on Thursday December 25, 2025 @08:27PM (#46388365)
I have a benchmark program I use, a solution to day 5 of the 2017 advent of code, which is all python and negligible I/O. It still runs 8.8x faster on pypy than on python 3.14:

    $ hyperfine "mise exec [email protected] -- python e.py" "mise exec [email protected] -- python e.py" "mise exec [email protected] -- python e.py" "mise exec [email protected] -- python e.py"
    Benchmark 1: mise exec [email protected] -- python e.py
      Time (mean ± σ):     148.1 ms ±   1.8 ms    [User: 132.3 ms, System: 17.5 ms]
      Range (min … max):   146.7 ms … 154.7 ms    19 runs

    Benchmark 2: mise exec [email protected] -- python e.py
      Time (mean ± σ):      1.933 s ±  0.007 s    [User: 1.913 s, System: 0.023 s]
      Range (min … max):    1.925 s …  1.948 s    10 runs
     
    Benchmark 3: mise exec [email protected] -- python e.py
      Time (mean ± σ):      1.375 s ±  0.011 s    [User: 1.356 s, System: 0.022 s]
      Range (min … max):    1.366 s …  1.403 s    10 runs
     
    Benchmark 4: mise exec [email protected] -- python e.py
      Time (mean ± σ):      1.302 s ±  0.003 s    [User: 1.284 s, System: 0.022 s]
      Range (min … max):    1.298 s …  1.307 s    10 runs
     
    Summary
      mise exec [email protected] -- python e.py ran
        8.79 ± 0.11 times faster than mise exec [email protected] -- python e.py
        9.28 ± 0.13 times faster than mise exec [email protected] -- python e.py
       13.05 ± 0.16 times faster than mise exec [email protected] -- python e.py
https://gist.github.com/llimllib/0eda0b96f345932dc0abc2432ab...
Re:Python 3.15's interpreter for Windows should be 15% faster by eru on Thursday December 25, 2025 @11:16PM (#46389181)
> [...] and I've just assumed the performance will still be as limited as it always has been...!)

Historically CPython performance has been so bad, that massive speedups were quite possible, once someone seriously got into it.

Re:Python 3.15's interpreter for Windows should be 15% faster by tom_ on Sunday December 28, 2025 @05:48PM (#46415305)
And indeed that has proven the case. But my assumption was that Python had been so obviously designed with performance so very much not in mind, that it had ended up in some local minimum from which meaningful escape would be impossible. But I didn't overthink this opinion, and I've always liked Python well enough for small programs anyway, so I don't mind having it proven wrong.