collinfunk 5 hours ago

Note, I am a co-maintainer of GNU coreutils. Whether that makes my opinion relevant, biased, or both, you can decide. :)

I really wished the documented their benchmarking methodology here, or at least cautioned the reader not to jump to conclusions based on the benchmarks shown.

GNU 'sort' performance can drastically be altered by the locale in use, the input, and the arguments given to the --buffer-size and --parallel options. GNU 'sort' is fairly conservative in how many threads it will use by default, and in my experience, much more so than uutils. This is because throwing more threads at 'sort' may make it faster (or may not), but also risks running out of memory. This is an issue with uutils, which is poor at deciding when to use external sorting:

  $ export LC_ALL=C
  $ for i in {a..z}; do yes $i | head -n $(numfmt --from=iec 512M) | tr -d '\n' >> input; done
  $ time sort input > /dev/null

  real 0m24.245s
  user 0m0.896s
  sys 0m19.161s

Here is the same command using the latest uutils commit compiled with 'make PROFILE=release':

  $ time uu-sort input > /dev/null
  Killed                     uu-sort input > /dev/null

  real 2m53.560s
  user 1m40.634s
  sys 0m59.847s

The process gets killed by the OOM killer. This is likely because uutils 'sort' decides to use 18 threads, instead of the 1 used by GNU 'sort'. I find it a bit frustrating that benchmarks are thrown out without any methodology or citations, because they are often trusted without question. These could be benchmarks from before uutils had localization, which was the case before 2025, and treated LC_ALL=en_US.UTF-8 as LC_ALL=C. In that case, of course it would be much faster than GNU coreutils, but it also means uutils would give you the wrong results for non-ASCII characters. There is, as shown above, much more considerations beyond speed that seemingly never get the time of day next to flashy benchmarks...

  • snowe2010 4 hours ago

    There’s none of those details because it’s an AI written article. It doesn’t even talk about the stuff it says it’s going to in the very first paragraph.

    • orthecreedence 4 hours ago

      That's a really great point, and demonstrates a deep understanding of how AI is changing the landscape of writing online!

      • knocte 3 hours ago

        Did I just read an HN comment written by an AI? Looks sycophantic enough

        • misnome 2 hours ago

          I believe that is "The Joke"

        • vdfs 42 minutes ago

          You are absolutely right! It's not just that you spotted it, it's how you pointed it out that make your comment upvote worthy

      • wseqyrku 3 hours ago

        changing the landscape of writi' you mean fucking shit up to the point of no return?

kmaitreys 2 hours ago

This topic has somewhat recently acquired a connotation where it yields a polarized response. People seem "tired" of the language and the episodes like Bun rewrite don't help, especially in current LLM-obsessed era.

Amidst this, just let me try to give my own experience with language while working in a field where it doesn't have much traction (scientific/numerical programming). A couple of years ago, after being tired trying to make Python faster, I was looking for a language to write simulation code in. Fortran (and C/C++) has been the go-to choice in my field for decades but I wanted to try a modern language. I tried Julia but the workflow didn't come naturally to me. Also by default, it also wasn't ahead-of-time compilable. Rust was my second choice but it's type system/design, expressiveness and tooling (rust-analyzer) won me over. I have written so much of it and I really enjoy writing it. Borrow checker isn't really an issue 99% of time when writing scientific code. And when it is (self-referential data structures), you can just use an arena (or something equivalent). The C/Fortran inter-op is great so it's still so easy for me to build my own abstractions on top for the more general stuff like solving ODEs and sparse matrices.

And of course, there is speed, memory safety and ability to parallelize things so effortlessly (rayon is magical), but I feel those were never the things that actually won me over. The language was just a joy to write.

  • willtemperley 1 hour ago

    I think this kind of topic is polarising because of articles like the Google blog that Jetbrains linked to here.

    That Google blog article is very confusing. It requires going about three links deep to actually understand and even then it's hard to validate the conclusions they draw because they don't provide a granular enough breakdown to actually do so.

    Given it's very difficult or impossible to replicate or validate Google's results here, little wonder it's polarising. Rust people like to just take the 1000x better tagline like this thread: https://news.ycombinator.com/item?id=45918616. The top comment even strips the context from the C++ stats:

    """ 5 million Rust LOC One potential memory safety vulnerability found Rust is 0.2 vuln per 1 MLOC.

        Compared to 
        C and C++ : 1,000 memory safety vulnerabilities per MLOC.

    """

    when the orginal article states:

    """ Our historical data for C and C++ shows a density of closer to 1,000 memory safety vulnerabilities per MLOC. Our Rust code is currently tracking at a density orders of magnitude lower: a more than 1000x reduction. """

    I don't particularly like either C++ or Rust, I'm a Swift dev, but I just find articles like the linked Google blog are really unhelpful to the discussion. Would it pass scientific peer review? I seriously doubt it. My more cynical side is tempted to think the Google blog article is designed as a divide-and-conquer tactic.

ameliaquining 4 hours ago

This post advocates rewriting incrementally instead of all at once. Just like Joel said back in 2000, and like everyone continues to always say to this day. Yet in practice, people don't actually do this; complete rewrites in Rust remain far more common than incremental ones, particularly when rewriting from a language other than C. The high-profile exceptions, like Linux, Windows, and Firefox, are codebases so huge and ancient that they obviously cannot be rewritten from scratch. When rewriting from scratch is an option, it tends to be taken.

The reason for this is pretty straightforward: Incrementally porting a codebase from another language to Rust (especially if it's not C) is a deeply unpleasant experience, because the interop tooling isn't good enough and you spend most of your time fighting it. Consider the case of rewriting from C++; in the simplest case, you use bindgen and cbindgen, which only work with extern "C" functions in both languages. So you effectively have to rewrite each API first from idiomatic C++ to C-in-C++, then translate to C-in-Rust, then rewrite again in idiomatic Rust. And then repeat for the next API. And so on. It's not going to take long for most programmers to go "screw it, I don't care what Joel said, at least when I rewrite all my work I'll be doing it in one language where anything can call anything else". cxx and autocxx modestly improve things, but still leave you with an impoverished API vocabulary and similar problems, and you still have to do the three-step rewrite for each API, one at a time.

This is also why TypeScript, Kotlin, and Swift worked so hard to have seamless two-way interop with JavaScript, Java, and Objective-C. Without that, they couldn't have credibly promised to replace the earlier languages (because large existing codebases where a rewrite wasn't economical would still be stuck with them), and so couldn't have gotten off the ground.

Crubit is supposed to fix this for C++-to-Rust, and I'm rooting really hard for it, but it's not there yet. For most other languages, a Crubit-like thing probably isn't even possible in principle, because the differences are too great.

(I'm not talking here about the use case where you started with a garbage-collected language but have hit a performance ceiling with it, so you rewrite just the most performance-sensitive parts in Rust, while continuing to develop the rest of the codebase in the original language. This is often a great way to use Rust, but it's solving an easier problem and so poses fewer difficult tradeoffs.)

  • rob74 2 hours ago

    > complete rewrites in Rust remain far more common than incremental ones, particularly when rewriting from a language other than C.

    Well yeah, that has obvious practical reasons: unless you're using C/C++, you can't really link Rust code with your codebase (or you could theoretically do it, but in a way that would affect performance and/or complicate your architecture). So, if you're going to do it at all, a full rewrite makes more sense.

tonyedgecombe 6 hours ago

For a brief second I thought JetBrains were rewriting their tools in Rust and we were going to get some performance improvements.

  • rob74 2 hours ago

    Yes, I thought that too. But no, that wouldn't be realistic. Their IDEs are massive, to rewrite them in Rust they would probably also have to rewrite half of the library code in the Java ecosystem.

    • norman784 2 hours ago

      Wasn’t their newer text editor/IDE written in Rust? I forgot how it was called and also didn’t followed up with their development.

BluSyn 5 hours ago

Small related anecdote:

Was just testing latest gen LLM capabilities, and decided to give it goal of rewriting a small opensource project in Rust. (Should be noted: was not some tiny library, but an actually useful network service).

It completed the entire rewrite from typescript to rust in about 2 hours, ~600k tokens used. Worked perfectly on first try with no follow up changes required. Memory and CPU usage now a tiny fraction of TS version (obviously). Rust code was simple, easy to read, accurate test suite, etc.

I was pleasantly surprised.

Obviously bigger code bases with more complex business logic will likely struggle here, but there are some advantages to "RIIR" when performance matters, even security benefits aside. Rust can help squeeze more juice out of old hardware; reduced memory footprint especially helpful with current RAM prices.

For small services where operational cost matters, having LLMs "rewrite it in rust" might be worth the spend.

  • sashank_1509 3 hours ago

    I’ve seen people do this and I’m always confused, do they believe they will never have to reason about the code ever again.

    I suppose if it is like the Zig Rewrite where essentially all development is being done by Claude, I can imagine this making sense.

    But in any other case, you had a codebase that presumably you wrote, you could reason about, you could refactor etc. and then you made it into a completely unintelligible code base, which even if written cleanly will take a long time to reason about. Typescript to Rust is not just syntax changes. It doesn’t make sense to me, unless you believe you will be completely out of the loop in managing this code in the future.

bragh 2 hours ago

That comparison figure of LaTeX vs Typst is ridiculous, choosing math-dense example for LaTeX vs classical markdown text for Typst. Yes, Typst syntax is much simpler https://typst.app/docs/reference/math/ but one doesn't need to make unfair comparisons to make Rust look better, Rust has a lot of good things going for it anyway, for example cargo.

joshdavham 5 hours ago

I would love it if jetbrains were to speed up IntelliJ. I started a new job writing Java professionally last year and, up that point, I had no idea that IDE's could actually be that slow.

My company gave me a brand new, beefy Macbook pro and that thing can barely handle IntelliJ sometimes...

  • antonvs 4 hours ago

    Just use VS Code. Its Java support isn’t the best, but it’s good enough and the rest of the IDE makes up for it.

    I feel like a lot of the love for IntelliJ is a sort of Stockholm Syndrome combined with relief at not using Eclipse.

    • wiseowise 2 hours ago

      But what about <some obscure feature that you use once in a blue moon and could’ve been achieved using some CLI faster than you could remember an IntelliJ shortcut for it>! It’s an IDE, not an editor!

      • moritzruth 24 minutes ago

        What CLI can I use to extract an interface from a class?

luz666 4 hours ago

I think he forgot to praise cargo.

(Imho, having cargo available is often already worth a RIIR.)

  • frollogaston 3 hours ago

    There have been times I needed to yell at Claude to rewrite some Python program into a faster lang because it was truly CPU-bound. I chose Rust purely cause of Cargo and the rest of the toolchain, despite being way more familiar with C++ (did use Rust but it was 9y ago). Didn't even care about the borrow-checker for that.

ldng 2 hours ago

Well they should rewrite their shitty sluggish new JS UI in Rust then.

dabinat 4 days ago

I think that a line-for-line rewrite in Rust like Bun did isn’t really getting all of the benefits of using Rust. A key benefit is utilizing the type system to make the borrow checker work for you by making certain checks happen at compile-time instead of runtime. Making it impossible for certain mistakes to occur is a massive benefit but you need to restructure everything to do so.

  • ameliaquining 4 hours ago

    The Bun rewrite is a long-term investment; the idea is that you initially compromise on idiomatic Rust for the sake of being able to keep shipping, but then the codebase becomes more idiomatically Rust-like over time. It will probably take another year or so to determine whether this works out.

    (Note also that Bun inherently needs to use a lot of unsafe because a large fraction of its internal API surface is interlinked deeply and pervasively with that of JavaScriptCore.)

fukaiall 4 hours ago

To me Rust is great where you don’t have to touch unsafe part. All the hard works are done by those skillful maintainers of the language and some core libraries such as tokio. I don’t see much value in it if either I have to work on the low-level stuff quickly (like implementing linked lists myself) or a complete high-level of i/o bound work like writing web servers.

jordiburgos 3 hours ago

> ... Part of this comes from auto-vectorization: the Rust compiler generates SIMD instructions automatically from a regular for loop, while most C implementations require hand-written SIMD...

I understand that their compiler in Rust is better. And any other language could compile it using the same SIMD instructions.

cube00 3 hours ago

> our attempt to give it an honest look.

Oh no, what are we hiding?

> introduces bugs you already fixed.

Isn't this why every bug fix gets a unit test?

I appreciate rewrite isn't always the answer but it's a strange post when the authors should be giving constructive ways forward so we move to Rust and then use their 1k star Django clone they link to.

Instead anytime a question is posed it falls back to "sometimes" and little detail after that.

Citing a nine year old paper instead of something newer or doing their own benchmarking wasn't ideal either.

ventana 4 days ago

I understand that's a guest post in Jetbrains blog, and these guests could very well be real people, project maintainers, conference speakers and whatnot, but I feel they used LLM so heavily that it reads like a slop. Pease do better next time.

  • ahofmann 5 hours ago

    Yes, there are quite a few signs of LLM usage in the post, which I also found annoying. But I also had the feeling that someone really cared about the quality of the text and I found only one strange/useless sentence in the post, which today has to be taken as a win, I guess.

  • DC-3 3 hours ago

    I had the same impression, and Occam's Razor suggests that the reason is because the author wrote it with the heavy assistance of a language model. But I do wonder if might also be a certain proportion of the tech industry that has started internalising LLM speak and uses it even in writing that is authentically their own.

shakow 41 minutes ago

> Typst is a good example of the readability argument:

I'm afraid the author completely missed the point here. Typst is not more readable than (La)TeX because it's written in Rust, but because its DSL was so designed. It could have been implemented in PHP that the result would be exactly the same.

Same thing with the auto-unroll/SIMD arguments. AFAIK, it's LLVM that's doing the job, there is nothing theoretically preventing a {language} compiler to obtain the same results.

Where Rust shines w.r.t. other similar languages though is that its strict memory model lets developers push further memory/concurrency optimization without sacrificing safety – which she highlights in the GNU/coreutils sort comparison.

CoolestBeans 5 hours ago

I think every project should seriously ask itself if it actually needs manual memory management. My hunch is that most people who think they need it, do not. If you really truly do need it, then yes Rust is a great way to get most of the benefits of garbage collection while still having manual control over memory.

  • kev009 5 hours ago

    I wouldn't consider Rust a manual memory environment. There are ways to do that at edges if needed, but it is otherwise very much automatic which is kind of the whole point of its design.

    • frollogaston 3 hours ago

      What most people mean when they say this is GC vs no GC. Rust is the latter. You have to care about ownership unless you're wrapping in Rc/Arc.

      • TonyStr 3 hours ago

        I agree with you, but I just want to point out that there are other seamless solutions to memory management like refcounting, used by for example GDscript (Swift? Perl?). You definitely wouldn't consider this manual memory management

        • yxhuvud 3 hours ago

          No, I would consider refcounting as variants of GC.

        • ghusbands 31 minutes ago

          Refcounting is indeed a form of GC (and the languages that want to handle cycles then need an extra form of GC on top of it).

wiseowise 2 hours ago

And here I thought they’re finally rewriting their slow, bloated IDEs. Shame.

biwills 4 hours ago

> And then there’s the Stack Overflow Developer Survey.

Honest question, at what point is the Stack Overflow Developer Survey not representative of the average software engineer, many (most?) of who no longer use Stack Overflow?

  • pelagicAustral 2 hours ago

    Good question. I no longer use SO at all, it's been years now, but I still get the yearly developer survey email alert, and I still take the time to answer, I take it most people doing the survey is the same...

piokoch 2 hours ago

"Typst instead of LaTeX"

Is this really an alternative? I would never replace battle proved TeX with consistent syntax, build for processing text, with great fonts, thousands of plugins for some Markdown mess, which is, in addition, paid.

Only because it is written in Rust, not in C.

  • mr_mitm 2 hours ago

    Yes it is, for many use cases.

    I'd argue the syntax is much simpler, more modern, and perhaps even more consistent (the fact that in TeX you can change the meaning of the escape symbol or the comment symbol is pure insanity IMHO). It can use any font, and the feature you know from LaTeX, a compiler, is free. Only the web application has some premium features. It's more like Overleaf. It's also several orders of magnitudes faster and has actually helpful error messages.

    The fact that it was written in Rust is less than secondary.

    Also, TeX was written in WEB, not C.

  • poulpy123 1 minute ago

    I don't think the main scientific journals accept it, so for that it is not a replacement. However, I would say that for most usages it's a good alternative even if it doesn't have all the ecosystem of 50 years of tex/latex