133 pointsby kbumsik7 hours ago16 comments
  • mwkaufma4 hours ago
    >> While the intent is not to call for competing proposals, we believe that now is a good time to discuss and propose alternative proposals as well.

    lol

    >> For example, rather than proposing one single concrete JIT implementation, it may make more sense for the PEP to describe a JIT infrastructure that can support multiple implementation strategies.

    poison-pill requirement

    >> We are setting a window of six months for a PEP to be submitted and resolved. If no such PEP is accepted within that window, the JIT code must be removed from the main branch

    so it's going to be removed from the main branch

    • scott_w3 hours ago
      No, it’s a simple request to fully investigate the options before committing a massive piece of work to Python. We’ve seen bad implementations of things land before and now live forever. And frankly, if the team can’t pull together a strong maintenance plan, it can’t be allowed to remain in main.
      • pjmlp2 hours ago
        So it will join PyPy and GraalPy in the corner.

        Python JIT history is full of drama, and no, Smalltalk, Common Lisp, Interlisp-D, SELF are just as dynamic if not more.

        • scott_w2 hours ago
          JIT in CPython has nothing to do with PyPy or GraalPy: it's its own thing. If they can't get a PEP accepted within 6 months then it's best that the code isn't weighing on the main codebase until an approach can be agreed, at which point work integrating it into main can restart. It's not an all-or-nothing situation.
          • pjmlpan hour ago
            > JIT in CPython has nothing to do with PyPy or GraalPy: it's its own thing.

            I haven't said otherwise.

        • onlyrealcuzzo2 hours ago
          And Ruby
  • Qem6 hours ago
    > For that reason, the Steering Council is formally requesting a Standards Track PEP be authored that the community can discuss and the Steering Council can formally accept (or reject), making the case for the JIT as a supported, non-experimental part of CPython: its guarantees, its maintenance commitments, and its impact on redistributors.

    I didn't notice the current PEP was a provisional one. Hope the new one gets approved. The experimental JIT was reported to finally breaking even and surpassing the default interpreter just a couple of months ago[1].

    [1] https://fidget-spinner.github.io/posts/jit-on-track.html

    • ksec6 hours ago
      >The experimental JIT was reported to finally breaking even and surpassing the default interpreter just a couple of months ago[1].

      Thank You. As someone who don't follow python closely I thought their JIT would be similar to what Ruby has.

      Not that Ruby YJIT or ZJIT is anywhere close to what JVM provides, but in this case it seems to be quite far ahead of Python.

      Which is surprising given how many major companies are using Python. May be because those using Python are not using it as critical part of work unlike Shopify and Stripe which is their core language?

      • bob0014 hours ago
        Python software is to a large extent either doing things in not-python (c, c++, rust, etc.) or doing things that are not cpu bound (io bound, async, etc.). If you're cpu bound then you can either take a 2x jit improvement or take a 10x non-python improvement. There's few companies of a scale where the non-hot path cost of 2x cpu is so massive as to be worth caring about.
        • thatguysaguy2 hours ago
          The python overhead of launching big ML jobs is nontrivial, so I think speeding that up would be meaningful. (I mean the initial tracing and other setup, not things once the GPUs are actually doing the work).
        • jbvlkt2 hours ago
          Also you can use projects like numba https://numba.pydata.org/
    • mike_hock5 hours ago
      Kind of a shit move to suddenly pull the rug once they've finally gotten it working. Should have been kept out of main from the start.
      • oliwarner4 hours ago
        The post clearly says the intention is to get a formal spec for formal integration.

        To leave their experimental phase they have to define some goals to meet and that requires making some architectural choices that still aren't decided.

      • bob0015 hours ago
        I suspect the recent "we updated the GC without a PEP and it went live and caused massive issues and we need an emergency point release revert" pushed for a greater degree of process overall.
    • IshKebab5 hours ago
      Sure but best case 15% faster clearly isn't worth the complexity of a JIT. It really needs to be at least twice as fast. Pypy pretty much achieves that on average.
      • Qem5 hours ago
        15% faster on top of a base interpreter that itself got 40%-50% faster on the same timeframe.
        • IshKebab3 hours ago
          Right... but it's still only 15% faster than a simpler alternative. In a language that is 50x slower than the alternatives. Clearly not worth it.

          Of course the counterargument is that they'll improve it and maybe in future it will be 100% faster... But that seems pretty dubious given the progress so far.

  • mellosouls3 hours ago
    Editorialised title.

    Development hasn't been paused (with negative implications).

    It's now considered significant enough that they've requested feature freeze in CPython main until governance/process questions are settled.

    • wavemode3 hours ago
      It's effectively a pause. In a project the size of CPython, and a subproject the complexity of a JIT, you can't continue work on a separate branch/repo without guaranteeing that there will be a massive amount of (both textual and semantic) merge conflicts down the road.
      • baqan hour ago
        Nah, you just merge main back every day or so.
  • oefrha4 hours ago
    Sounds reasonable given the recent YOLO GC debacle https://discuss.python.org/t/reverting-the-incremental-gc-in....
    • wavemode3 hours ago
      That seems entirely unrelated?
  • simonw4 hours ago
    "Asked to pause development" isn't entirely accurate: they were asked to pause landing new features (as opposed to bug fixes) on the cPython main branch.
    • mindcrime3 hours ago
      ... and only until the whole thing can be fully formalized with an approved PEP. I'm no Python insider, but that doesn't sound horribly controversial to me.

      And yet, I have a hunch it will piss off a lot of people nonetheless and lead to much outrage and wailing and gnashing of teeth. Hopefully it all works out in the long run.

  • 123987615 hours ago
    That was kind of overdue. The project started five years ago while massively overpromising.

    They should perhaps have kept it in a separate branch back then, but now is the next best time.

    CPython's selling point was that it is simple, fast enough with C extensions and the code was accessible. Complicating the code base for occasional 50% speedups (and regressions ...) just isn't worth it. There are so many other languages that fill that need.

    Now, I hope that the PEP does not overpromise again and is accepted because of Instagram pressure. Instagram can keep its own JIT fork or switch to PHP, Go or whatever.

    • ameliaquining2 hours ago
      This hasn't been true for a very long time. Python's major selling points these days are the accessibility of the language and the extensive ecosystem. A vanishingly small fraction of users ever look at the implementation internals. Telling people "if you don't like it, switch to a different language" is particularly unhelpful because rewrites are rather famously expensive. Making things more complicated for the few maintainers, so that they work better for the millions of users, is easily a worthwhile tradeoff.
      • ptx2 hours ago
        Who is going to pay for maintaining the massively more complicated implementation though? Microsoft pulled their funding of the Python team, and even if they hadn't I think there' a danger in making Python so complicated that it collapses under its own weight without the continued support of some giant corporation.
  • kelvinjps105 hours ago
    What a shame it will receive a halt when they where starting to make progress I know that after submitting the pep it will go back to development. But t would have been better to just keep the development and the pep for an actual release or continue and if gets rejected ask them to stop
    • Qem5 hours ago
      > What a shame it will receive a halt when they where starting to make progress I know that after submitting the pep it will go back to development.

      To be fair, the apparent lack of progress of the JIT before was in part due to the same team improving the base interpreter by 40-50% between 3.10 and 3.14. The JIT implementation was pursuing a moving target. It was not some static milestone. Kudos for them.

  • questiuner3 hours ago
    Why was PyPy abandoned and not embraced by Python? NIH?
    • kzrdudean hour ago
      The short answer is that CPython didn't want to break compatibility with lots and lots and lots of Python modules implemented in C, so it was never viable to let PyPy seamlessly replace CPython.
    • JulianWasTaken3 hours ago
      (PyPy was not abandoned.)

      I assume you might mean to ask "why wasn't PyPy adopted in some formal way into CPython" rather than a separate project, for which the answer is at least partially likely to be because it's a completely separate implementation.

  • dist-epoch2 hours ago
    There is a large graveyard of JITs and JIT-adjacent projects for Python.

    By now it should be clear to anybody working on Python JIT that the probability of failure is 90%.

    The future is probably rewriting performance critical Python code in Rust instead of trying to fix Python.

    Or maybe a future LLM could add a JIT to Python in an effort-run.

  • Fraterkes2 hours ago
    People in this thread writing conspiracy theories over the biggest language in the world requiring a bit of bureaucracy lends some credence to the idea that programming is not real engineering.
  • IshKebab5 hours ago
    Seems reasonable. As I understand it the JIT implementation has not really been successful anyway.
  • jhayward5 hours ago
    > While the intent is not to call for competing proposals, we believe that now is a good time to discuss and propose alternative proposals as well.

    If I were a contributor I would read such language as saying "we have no respect for you or your intelligence, so we'll just straight up gaslight you and expect you to accept it."

    The dictum can't be read literally - it has to be read like the manipulative, narcissist-speak that it is. And what it's telling you is - get out.

    • _old_dude_5 hours ago
      I agree. And the next section is very clear that they want to kill the project.

        > For example, rather than proposing one single concrete JIT implementation,
        > it may make more sense for the PEP to describe a JIT infrastructure that
        > can support multiple implementation strategies.
        > Since many different and promising JIT tracing approaches continue to be proposed,
        > we believe the infrastructure should make it easy to experiment with and evaluate
        > those approaches within CPython rather than be highly coupled with a single strategy.
      
      Allowing multiple strategies is far harder and as far as I know, JIT tracing is still unproven.
      • zem3 minutes ago
        I'm a big fan of the pluggable jit strategy (I even gave a brief presentation about it at an earlier pycon). the idea is that you identify the seams in the interpreter where the jit interacts with the main interpreter loop, and then provide a clean mechanism for the built-in jit to be replaced by something else that works with the same api surface. it's a bit harder than letting the built-in jit be tightly coupled to and intertwined with the rest of the interpreter but certainly not far harder, and the work to get this sort of clean separation will help keep the jit maintainable even if there is never a second jit.
    • Retr0id4 hours ago
      I think this is uncharitable, it's not like they're inventing new requirements that weren't there before. The PEP process has existed the whole time.
    • bob0014 hours ago
      I suspect there were people who had alternative proposals which got implicitly blocked by this 5 year effort. Letting a subgroup run wild without proper process is not good for a project this large.
    • KaiserProan hour ago
      > The dictum can't be read literally

      out of curiosity, why not?

      I mean it seems like they want to get a full spec of what JIT should look like in main? given the faff that hapened with the GC removal, I can sort see why they'd want to do this properly. Especially now that it seems like its practical.

    • simonw3 hours ago
      "it has to be read like the manipulative, narcissist-speak that it is"

      That's a very strong claim. I'm not seeing that at all. What causes you to interpret it that way?

      • mike_hearn2 hours ago
        It's because they say they don't want to call for competitors and then immediately do so in the second half of the same sentence. It probably wasn't written with bad intent, but you can see why people might find it a strange choice.
  • andrewmcwatters5 hours ago
    [dead]
  • OutOfHere5 hours ago
    Losing development momentum for a beancounting reason like this one is a sure way to kill a project. It works every time. Once development is halted, it is very difficult to pick it back up.
    • bob0015 hours ago
      Python isn't a side project to yolo on. Updating the GC without a PEP caused massive issues for actual people using Python. If you want to impact software used by millions of developers then you better be willing to handle a bit of process.
    • simonw4 hours ago
      They're not being asked to halt development, they're being asked to halt landing new features on the cPython main branch.
      • 18 minutes ago
        undefined
    • kzrdude4 hours ago
      The JIT project already lost a lot of momentum when the people working on it lost their jobs (at Microsoft)..
  • nmstoker6 hours ago
    • elpocko5 hours ago
      Don't bother clicking, that post got 0 attention. Not helpful, mate.
      • nmstoker3 hours ago
        It is literally the same link, it was the original and it had the correct title rather than the editorialised one here.

        At the time I posted it, both were pretty lacking in attention, so it made sense to direct to the earlier of the two.

        • elpockoan hour ago
          It would make sense if there was any activity on that older post. A 12 hour old post with no comments is dead, linking to it is a waste of time, especially for those who click on it to find 0 comments.

          I did click on your link, it was a waste of time and that wasn't very nice.

  • sitkackan hour ago
    I have used Python as my main language since the late 90s and it has been over the last decade and half been getting more unserious.

    It would be nice if cpython opened up a bit, pluggable GC and JIT would go along way towards reducing this manufactured drama.

    It wasn't cool to see PyPy or Stackless getting sidelined.

    • woodruffwan hour ago
      This isn't really a substantive comment, and to at least one extent it's trivially falsifiable (15 years is before Python 3 became usable, so that alone is a "serious" change in the language).

      > pluggable GC and JIT would go along way

      One of the points mentioned in the linked discussion is explicitly about ensuring that the JIT design enables multiple implementations.

      • sitkackan hour ago
        Python 2 to 3 transition was also unserious.

        The flippant attitude of cpythons wrt the standard library is also unfortunate.

        Please with your substantive comment comment.

        • woodruffwan hour ago
          It seems to have been serious enough; I don't think Python would have succeeded as a language if they hadn't done Python 3.

          > Please with your substantive comment comment.

          I think binning things as drama isn't substantive, particularly when noting about the linked conversation seems dramatic. I also think they're actually talking about the thing you want (pluggable JIT), so the objection seems incongruous.