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Writing New System Software

borud.no

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Re: Writing New System Software

#11

Post by cjfd »

rightbyte wrote: post #8
cjfd wrote: post #7

I think C++ is just fine. Memory management is not that hard anymore using smart pointers. I prefer that to java at any time of the night or day. Such an ugly verbose language. The buzz word laden stuff is actually quite bad. I have seen what could be rather simple systems be very unreliable and slow because of the many microservices all in their own container. Then if one is sensible enough to avoid that there is an…

Smart pointers has some overhead though, even unique_ptr. I like to use raii to handle normal pointers. For many programs memory leaks can just be handled by exit, too.

This would seem to be a very micro optimization, though. If you are in a tight loop, sure, but otherwise I would say that smart pointers are a rather low price to pay. And if you are in a tight loop it may be better to try to avoid memory allocations altogether and try to reuse objects instead. In any case the price of smart pointers is orders of magnitude smaller than the price of what passes as 'modern' software development.

Re: Writing New System Software

#12

Post by rightbyte »

wapxmas wrote: post #5

"You can write reasonably fast software in almost any decent language (with a few exceptions)." - this is entirely wrong statement.

Ye I feel the author has no clue what he is talking about.

"I can appreciate the “macho factor” of being able to write fast software in C or C++ (or even Objective-C), but most people aren’t going to be able to do that"

I mean, C is probably the simplest tool to write fast software with, since there are so few hidden costs to know about. Like strdup does a malloc. What else?

In C++ you have to know implementation details of the standard lib and calling conventions to write fast code. Java, C# and Go the same but abit more.

For e.g. Haskell and Julia you need to know quite much to reason about what code will be generated and good luck doing that with complex code.

Re: Writing New System Software

#13

Post by cjfd »

Glamhoth wrote: post #10
rightbyte wrote: post #8

Earlier quoted context omitted.

Smart pointers has some overhead though, even unique_ptr. I like to use raii to handle normal pointers. For many programs memory leaks can just be handled by exit, too.

unique_ptr has zero overhead

This appears to be incorrect. I have seen a cppcon talk about that. I think it may have been this one: https://www.youtube.com/watch?v=rHIkrotSwcc . On the other hand, it is a very, very tiny minority of programmers who have to care about an overhead as low as this. Most of us should not waste one microsecond of our thinking time on this.

Re: Writing New System Software

#14

Post by aastronaut »

incanus77 wrote: post #4

> Just look at how badly Apple struggles with memory leaks now that they have switched CPU architecture and all the latent gremlins in their code start to manifest. What the hell is this referring to?

My guess would be https://www.macworld.com/article/549755/m1-macbook-app-memor...

Re: Writing New System Software

#15

Post by vnorilo »

stevekemp wrote: post #9
mem0r1 wrote: post #6

I tend to disagree. (Modern) C++ is an incredibly powerful programming language. Contrary to some other languages it gives the developer maximal freedom and does not impose a particular way of doing things on the developer.

In theory, yes. In practice few people use C++ fully, too often you find in-house "style-guides" vetoing specific things, such as Google's famous "no exceptions". At the point you rule out using available facilities of the language you might as well use something else.

Practical, old languages tend to do this. In C++ or Common Lisp, which share little other than being multi-paradigm (unopinionated), it is fairly common to have house styles or accepted subsets.

Languages that try to build in some "house style" are my personal dystopia - such as early Java or current Go. Which does not say they ate not effective, just that I personally hate the philosophy.

Re: Writing New System Software

#16

Post by mikewarot »

There are multiple types of system software, and it wasn't specified which.

If you're talking about Embedded or Kernel Systems, writing a layer that can efficiently and securely multiplex and abstract the hardware requires a much different set of tools than the rest of the system. Here I disagree with the author.

Once you're no longer concerned with directly probing the hardware, it seems far more appropriate to worry about correctness, then complexity/performance. C/C++ are unlikely to be the best match to the needs of the system and the programmer. Here I agree with the author.

Re: Writing New System Software

#18

Post by JonChesterfield »

Glamhoth wrote: post #10
rightbyte wrote: post #8

Earlier quoted context omitted.

Smart pointers has some overhead though, even unique_ptr. I like to use raii to handle normal pointers. For many programs memory leaks can just be handled by exit, too.

unique_ptr has zero overhead

Kind of true for unique_ptr as a C++ construct.

Sadly if the platform ABI is not ignored there is (usually? might be free on some platforms) overhead relative to a void* when passing one between functions.

Also there's the usual code size / compile time hazards of templates.

Re: Writing New System Software

#19

Post by dan-robertson »

cjfd wrote: post #7

I think C++ is just fine. Memory management is not that hard anymore using smart pointers. I prefer that to java at any time of the night or day. Such an ugly verbose language. The buzz word laden stuff is actually quite bad. I have seen what could be rather simple systems be very unreliable and slow because of the many microservices all in their own container. Then if one is sensible enough to avoid that there is an…

This feels like Stockholm syndrome to me.

1. I’m amazed that you call Java ugly and verbose but recommend C++. Apart from files not needing to be classes in C++, they feel similarly verbose to me with C++ slightly winning on ugliness.

2. I basically don’t believe that memory management is not hard. The reason is that plenty of programs written in ‘modern’ or ‘safe’ C++ in the style you recommend continue to have plenty of memory unsafety based bugs, crashes, and vulnerabilities.

P.S. Most async systems try to keep things on a single thread. Their main purpose is allowing a higher level of parallelism than can be economically achieved with threads, and normal good async style is to have most things non-async and therefore single-threaded. On Linux, a lot of the purpose of the thread pool is doing system calls that are blocking. io_uring makes it less necessary but many people use kernels that are too old.

Re: Writing New System Software

#20

Post by dan-robertson »

vnorilo wrote: post #15
stevekemp wrote: post #9

Earlier quoted context omitted.

In theory, yes. In practice few people use C++ fully, too often you find in-house "style-guides" vetoing specific things, such as Google's famous "no exceptions". At the point you rule out using available facilities of the language you might as well use something else.

Practical, old languages tend to do this. In C++ or Common Lisp, which share little other than being multi-paradigm (unopinionated), it is fairly common to have house styles or accepted subsets. Languages that try to build in some "house style" are my personal dystopia - such as early Java or current Go. Which does not say they ate not effective, just that I personally hate the philosophy.

Both C++ and Common Lisp suffer a huge accumulation of historical baggage. It is this that makes the languages problematic, not being multi-paradigm. Common Lisp has first/rest as well as car/cdr. It has streams and numbers and the functions on them seem generic but aren’t (always) generic functions. It still has rplca despite (setf car) being a valid function name.
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