9 ms·

Say I have a new project to start today. I need pick a language to use: 1. a well-tested language 2. can not use garbage collector due to *performance* req

• bugfix-66 4y ago
  Go's garbage collector is faster than you imagine. Have you used it? Go is a good replacement for C and C++ for almost all purposes. Most purposes where Go is inapplicable should be using explicit SIMD (GCC intrinsics) or CUDA C anyway. The others purposes where Go is inapplicable are low-level real-time stuff that should be written in C for a specialized software stack (e.g., software in a car).
  • synergy20 4y ago
    Go will give me VSS of hundred of Gigabits on a MIPS board that has only 64MB memory, it's a known 'feature' by design. Its binary size is at least 10x larger than C/C++. Go also has the stop-the-world GC problem, GC is great but it does have a price tag. I like Go a _lot_ and use it in some projects, but I certainly will not claim it can replace C++ 'generally', not at all.
    • bugfix-66 4y ago
      Sure, you can always find extremely constrained, embedded, or real-time safety-critical applications where only a carefully chosen subset of C is applicable. You shouldn't be using the sprawling C++20 there, either. But for pretty much everything else (see the caveats in my comment above) you are better off, a lot better off, using Go.
      • jandrewrogers 4y ago
        C++17/20 is superior to Go, and widely used, for anything that looks like high-performance data infrastructure, which is a broad class of software. There are classes of common architectural optimizations that aren't feasible with a garbage collector because of how it interacts with scheduling and CPU caches. Even 1 millisecond for a GC pause -- often considered "low latency" -- is much too slow when standard operation rates are tens of millions per second. Go is very good for many things but it does not offer competitive performance for these types of applications because design elements that have a large impact on throughput are poorly supported.
  • doliveira 4y ago
    What are people using C and C++ for that you can comfortably use Go instead?
    • bugfix-66 4y ago
      For example, I work at a company (a company you hear about daily here on Hacker News) that has a compiler generating linear algebra kernels. The compiler is a huge assemblage of C++ templates, stitched together with a little Python. The generated code is in an assembly language for a highly parallel machine, and needs to be heavily optimized down to the cycle. But the compiler itself does NOT need to be so minutely tuned. It needs to be maintainable and it needs to allow easy development of complex code generators. Go would be a great choice for the compiler. Instead, we struggle with C++ templates, CMake'ing our code slowly and with absurd complexity, modifying the compiler slowly and with great difficulty...
      • spyremeown 4y ago
        I've read all of your comments and I commend you trying to illuminate these people. Some of them seem to be living in the 1990s, spewing the usual hocuspocus about programming languages, the kind of thing you hear once and it becomes a myth. It's like people don't want to reevaluate their choices, and it's insane we keep using this god-forsaken language when we have much better tooling, as you said.
      • pclmulqdq 4y ago
        Honestly, it sounds like C++ is just a poor choice for this project, since you are not so interested in performance and you are a lot more interested in developer speed. It is not an example as to why Go is a good replacement for C++ in almost every project. This is a case where you could replace C++ with any business-logic-oriented programming language and you would be happier. It just so happens that your language of choice is Go (and presumably the tech lead's language of choice is C++ for some unknowable reason). Also, you should not discount compiler speed completely. You, yourself, were upset at the speed of a compile process. All of your users are going to be waiting to get things done while the compiler is running, so you might want to do some math as to how much a 10% slowdown would cost in developer salaries. The makers of gcc, LLVM, and clang spend a lot of effort on improving the speed of their compiler to make sure that you have minimal time waste.
  • galangalalgol 4y ago
    Even with version 1.18 the median is 3x slower than c++ in the benchmark game. And most of those programs don't even exercise the GC (other than binary trees benchmark). If you are targeting a quadcore arm embedded type thing with no gpu, go is going to take something that saturated one core, and make it saturate 3, if you are lucky enough it is easily parallelized. Even when a gpu is available, it often isn't a good fit to the problem. I like go, I use it on occasion. If I stick to the simple stuff it is really easy to think about and if it is just a back end on a big server, why not. But that is a niche case for me. I usually prototype in matlab, then implement in c++, and yes, often cuda too, but I think saying that go is almost always a drop in for c++ is missing the vast majority of what c++ is used for. Go is not a systems language, it benchmarks slower than many vm lamguages like java and c#. It's gimmick is that it compiles really fast and is easy to reason about, so it is good for velocity. But it sacrifices a lot for that. FFI compatibility, and runtime speed foremost. Sometimes those things don't matter. But for systems programming, dsp, embedded, or AAA games they are deal breakers.
    • bugfix-66 4y ago
      I don't know if you've read the benchmark code from The Benchmark Game, but anyone who has looked at the code takes those results with a grain of salt, or discards them entirely. For example, the C/C++ implementations use arena allocators, and they could do the same for the Go implementations, but they don't. The Benchmark Game is a joke. Here it is, for anyone who wants a good laugh: https://benchmarksgame-team.pages.debian.net/benchmarksgame/index.html https://benchmarksgame-team.pages.debian.net/benchmarksgame/...
      • galangalalgol 4y ago
        I disagree, but they do take some effort to use effectively. Isaac (or someone) has spent a lot of time segregating out idiomatic simple, and overoptimized solutions. I have looked at the programs, and within the idiomatic programs similar to the types of stuff I do (not a lot of allocation) go varies between 30% and 300% more CPU time. And I have used it as I said. Because go is compiled to native people keep suggesting it is a systems language. Fortran is compiled to native too, but I don't want to write a kernel driver in it. Go has a huge niche, back-end. I think it has plenty of competition there with java and c#, but I reach for go because it makes things quick and easy. I might learn c# if back-end was my day to day, but it isn't. Using c++17 (don't know 20 yet) for very small embedded targets works fine, easy FFI into the BSP, small to no runtime depending on usage. Trying to target that with go would add a lot of extra challenge. I think something like rust or preferably a subset of it for c++ ise cases makes sense. My next project without a GPU I have penciled in rust on the plan. The other developers are excited. Still too hard to use gpu with it. Or rather too immature. The other developers like go too, but throughput will be critical without the gpu, and every little bit will count. And for numeric code it wouldn't just be a little bit of a hit. I wouldn't even suggest julia, and that is as close to a do-it-all language as I have seen.
  • surajrmal 4y ago
    go has other problems that preclude it from being a good option including binary size, memory usage, and portability. There are certainly a lot of places it is a good choice for, but I can't really imagine using it anywhere I use c++ today.
    • bugfix-66 4y ago
      Portability? Are you saying Go has portability problems? Can you elaborate on that very surprising claim?
      • synergy20 4y ago
        when you talk about macos/windows/linux without CGO yes Go is very portable and easy to use, when you need CGO, or you need work on other architecture or OSes, Go is pretty much a no-go. and c/c++ are still the only ones close to the claim "runs on everything".
• Koshkin 4y ago
  Sounds like Fortran to me.
  • scottLobster 4y ago
    Fortran is easy to hire for?
    • phao 4y ago
      For numerical and scientific (high performance) jobs, possibly not that much harder than C++. For other jobs, I doubt it and would stick to C++. The issue is that, for example, you might be getting people with poor software engineering training per se. You risk hiring some very smart phd that writes code that works and runs really fast, but isn't that readable, extendable, maintainable, testable, etc.
      • llanowarelves 4y ago
        Your second paragraph describes what I see with Python ML guys.
        • phao 4y ago
          I see it in a lot of matlab code as well.
        • int_19h 4y ago
          It's generally true for ML and data science, regardless of the language.
• logicchains 4y ago
  > what options do I have? I have to pick up c++ in this case. it falls to the saying "a language is either blamed, or nobody uses it". You could just use C.
  • synergy20 4y ago
    or use a subset of c++ that does everything c does, plus OOP, RAII and smart pointers for free, and it compiles and links with c code smoothly as well. the only price to pay is that libstdc++ runtime must be present, which is just a few MBs that can even fit for small embedded boards.
    • alar44 4y ago
      This is what I do. Write C in C++. You don't have to use all the fancy new shit. I'll never understand why people get so upset about it.
      • bluGill 4y ago
        That C in C++ id the part where most of the serious bugs in C++ come from
      • ncmncm 4y ago
        Then you are writing bad C++ code. The new features are added specifically because they enable writing better programs. Avoiding them means you are choosing not to write better programs. It is allowed, but not a thing to brag about. That does not mean every program has to use every feature. But when there is a choice between the new way and the old way to do something, the new way is very probably better. Passing a reference, where you can, is better than passing a pointer. Passing a lambda is better than passing a function pointer. New for-loops are better than old for-loops. A unique_ptr is a better member than a naked pointer. A compiler-generated destructor is better than a hand-coded one. And so on.
        • alar44 4y ago
          Absolutely, but none of those are really that new. I guess I'm talking more about boost libraries and that stuff. I just can't be bothered and it doesn't matter for anything I need to write.
• the_af 4y ago
  Honest question: is it easy to find good C++ programmers these days?
  • synergy20 4y ago
    that's a good question, I have yet to find a good beginner friendly modern c++ education material, be it a book or some course, that can make c++ learning simpler, to the point and enough to start to work with the language before diverting into those deep concepts. Someone needs to write a c++ 101 book, followed by 201 and 301 for beginner, intermediate, and advanced users.
    • user432678 4y ago
      “C++ Crash Course” by Starch seems to be such a beginner’s book, can’t recommend it enough. Although, I was learning C++ mostly for hobby projects.
      • synergy20 4y ago
        a good book indeed, hope it will have an updated version for c++20/23, which arguably is the most important release since c++11, new stuff such as ranges, std::span even concepts could be added now. I think this book is a bit tough for beginners though.
  • deleted 4y ago
    [deleted]
  • jandrewrogers 4y ago
    I think it is significantly more difficult to find programmers with domain expertise in the kinds of applications C++ is often used for than the language itself. There are quite a large number of good C++ programmers who have never worked anywhere close to the metal, OS, high-performance, etc, and those skills are often more difficult to learn and come by than the language. A large amount of C++ development is still focused on enterprise and UI apps, even though one could argue that it is not the best language for that purpose.
  • 4y ago
• Xeamek 4y ago
  >Java for enterprise or Android >C# if you are windows developer Picking Java over kotlin for android, or lumping C# into "just for windows" bucket is exactly the ignorance that leads you to "we don't have choices" conclusion. If you always default to literally top1 language for given domain, then how can you expect to have multiple choices? I'm not talking about using some brand new gimmick that came out yesterday and will die tomorrow, but if you aren't able to leave your comfort zone even just-so slightly to update your stereotypes about given given domain and its trends, then by definition you won't see the alternatives.
  • synergy20 4y ago
    same can be said to typescript, did not mention them to make the point.
  • f1shy 4y ago
    TBH I was shocked by "Python for machine learning". I do not know where that comes from. Maybe because some important toolkits are available for Neural Networks? But machine learning is not neural networks... you can do it with NNs, but there are so many other algorithms... I'm really surprise of this kind of posts in hacker news. I thought the audience here has other experiences.
    • plonk 4y ago
      Python is the main language for PyTorch and TensorFlow, there are few ML frameworks more complete than Scikit-learn, I'm not aware of an equivalent to NumPy in other languages, and this list is probably missing other things I don't use. What's the alternative for quick ML prototyping?
      • didibus 4y ago
        R, Matlab, Julia are some common alternatives. Java/Scala I've also seen, specifically things around Spark ML, and Spark compute. That said, Python is definitely the most common nowadays I'd say.
    • 4y ago
• phoehne 4y ago
  The way I look at it is we're in a transitional period. A language like Go or Rust can replace some of the C++ lift, but we're not sure because they're not a large body of experience with those languages. I suspect, but can't say with any certainty, that we'll wind up in a world where the use case for C++ shrinks significantly. Rust and Go will eat into the share of new Greenfield systems that would have normally gone to C++ or even C. I like to live in the embedded world and there I think Rust will shortly start to push out C and C++ at the wide-spread, commercial level. This is where my head is at, maybe it helps you formulate your opinion: First, embedded C++ is not the same a full C++ (with features or library parts missing to accommodate the constrained environment). So I might never see some of the C++2x or even C++1x features. I really don't care about the C++2x standards since I might not see them in the next 10 years. Second, memory and concurrency issues are real, even when you don't allow dynamic memory allocation after the system is initialized. We test, then test, and then run more tests, and turn on a lot of linters and analyzers but at the end of the day, they're bandaids. You can write terrible code in Rust, but you have to work harder to do it. Third, if you really need an environment where memory is as fungible as play dough but want something portable (like inside a kernel), there will always be C. Setting up a C callable environment from assembly is well understood. In theory, calling into Rust shouldn't be any harder. But reading disassembled object files from C is generally reasonable assembler for the C I wrote. I haven't really tried doing that with Rust. Fourth, it will take 5 years or so, but eventually we'll see commercially supported RTOS implementations for Rust that help companies to shield themselves from liability. For example, something like Threadx (AzureRTOS now). This will help push money in a virtuous cycle of better tooling -> more projects -> more money for tool venders -> better tooling. Fifth, there will be Rust bindings to cover just about everything you do with C++ now (like game development) with high quality, idiot-proof, and portable semantics. You will find that junior developers or fresh-outs will have their skin crawl when asked to write "unsafe" code. Sixth, there's counter evidence to support a lack of adoption of new languages. Ada provides many of the same concurrency and memory safety guarantees as Rust, and has been available since 1983, but it is not widely adopted. It is harder to use and requires significant developer training. If Rust is significantly more challenging for developers, it may go the way of Ada. But that's in the future. If I had to start a new project today (for a braking system on a train, for example), I would start with C, a validated RTOS, and commercial toolchain. If I had to light up my kid's halloween costume? Embedded Rust as a learning exercise. The rendering engine for a VR headset (with limited batter and compute), probably C++.
• oconnor663 4y ago
  I think depending on the type of project, Rust might already be there. A couple of bullets raise questions: > ready to use tooling support This really depends on the use case. If the tooling you're looking for is "Unreal Engine", then Rust is definitely not there yet. But if you want to write network services, databases, CLI tools, etc., I think Rust has been fully viable with good tooling and library support for years now. > easy to hire if project expands No doubt hiring experienced Rust developers is hard, because there aren't that many yet. But anecdotally, training Rust developers is much easier than training C++ developers. Rust makes it easier for one or a few experienced folks to have confidence that a larger number of less experienced contributors aren't introducing stability or security issues.
  • f1shy 4y ago
    And also you have to check the quality, not only quantity... yes, you get many people if you search "c++ developers" but how good are they? I think people who are into Rust are very motivated, curious people, with some experience. I would really like a study of that, btw :)
  • slaymaker1907 4y ago
    As somebody who writes C++ for my job, I don't think the tooling is particularly good so it's funny to me when people talk about that. Languages like Java or Python have good tooling, but C++ is a dumpster fire in terms of tooling.
• phao 4y ago
  I wonder how much of (2) is speculative and how much of it is a real need in actual projects.
  • f1shy 4y ago
    In my experience 99% speculative and WRONG. Who said: "early optimization is the root of all evil"? :) Today more and more is possible to have a GC without terrible performance issues. Some weeks ago I read an article here in HN, about LISP used for safety critical systems. That bad fame of GC comes from the early versions of Java... but I've been using GC languages a LOT, and never had those "stop the world" moments.
    • ncmncm 4y ago
      The expression is "premature optimization". And, Donald Knuth. GC overhead is always hard to measure except end-to-end, because it is distributed over everything else that happens. Cache misses, TLB shoot-downs. Mitigations are very difficult to place. Practically, you usually just have to settle for lower performance, and most people do. Double or triple your core count and memory allocation, and bull ahead.
    • Gibbon1 4y ago
      Not my bailiwick but I feel like early Java's problem was a combination of everything not a simple primitive is an object that goes on the heap plus a GC optimized for batch throughput vs latency. Bonus it's Java all the way down to the bitter end. I'm with you. One should look at latency requirements and the ratio of profit vs server costs when making a decision. AKA when your product generates $250k/month, you're paying three programmers $40k/month, and your AWS bill is $500/month isn't the time to try and shave pennies.
  • jandrewrogers 4y ago
    The negative performance impact of GC in performance-engineered code is neither small nor controversial, it is mechanical consequence of the architecture choices available. Explicit locality and schedule control makes a big difference on modern silicon. Especially for software that is expressly engineered for maximum performance, the GC equivalent won't be particularly close to a non-GC implementation. Some important optimization techniques in GC languages are about effectively disabling the GC. While some applications written in C++ are not performance sensitive, performance tends to be a major objective when choosing C++ for many applications.
• didibus 4y ago
  > I played with nim, ziglang and Rust, but it's hard to use them for real product developments at this point for me What made it hard? For example, Rust seem to fit your bullet list.