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Why Rust for Low-Level Linux Programming?

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Re: Why Rust for Low-Level Linux Programming?

#11

Post by TheMagicHorsey »

Is there any reason why embedded software for autonomous vehicles is still being written in C/C++? This last week I was talking to a friend at a company that makes a small autonomous vehicle. During testing their prototype suddenly went off in a straight line. They had to pull a safety to halt the vehicle or it would have gone straight forever into the Pacific Ocean. Turns out there was an unsafe access to a variable in memory, which had not been caught with their software and hardware test platform, even with thousands of virtual sorties.

If their code was written in Rust, that sort of bug could not have occurred.

Re: Why Rust for Low-Level Linux Programming?

#12

Post by PeCaN »

frankmcsherry wrote: post #7
Scarbutt wrote: post #2

Rust reduces the amount of state I need to keep track of in my brain. I doubt it, the mental overhead of doing "safe memory programming" in Rust is very high. Edit: all good replies, want to clarify and forgot to mention that I was comparing to languages with a GC, since I'm seeing Rust being used for lots of stuff, in a general purpose programming language sense (like creating web frameworks for example). Also, for…

Not my experience, fwiw. Rust does a great job of handling the mental overhead (am I allowed to mutate this? who owns this? what is the contract for that?) for me.

Exactly. Compiler-enforced ownership and lifetimes _dramatically_ reduces the mental overhead of memory management compared to C. It also saves time from having to run things under Valgrind and ASAN just to make sure I didn't mess up.

Re: Why Rust for Low-Level Linux Programming?

#13

Post by steveklabnik »

slimsag wrote: post #5
Scarbutt wrote: post #2

Rust reduces the amount of state I need to keep track of in my brain. I doubt it, the mental overhead of doing "safe memory programming" in Rust is very high. Edit: all good replies, want to clarify and forgot to mention that I was comparing to languages with a GC, since I'm seeing Rust being used for lots of stuff, in a general purpose programming language sense (like creating web frameworks for example). Also, for…

I don't remember the source.. but somewhere someone said that the borrow checker would get in the way until you've learned to a certain point, then after that point developers tend to think in terms of the borrow checker by default and it _works for them instead of against them_. Besides, you're still going to be doing safe memory programming regardless of whatever language you use. (unless you're just saying "writin…

This is consistent with a lot of people's experiences with Rust. Some people haven't even noticed when the mental bit flipped for them, "Oh wait, I just realized I haven't fought the borrow checker in a while..."

Of course, some people still don't like it. Not every language can be to everyone's liking, a plurality of languages is a good thing. Plus, we do have some stuff in the pipeline to increase the number of programs the borrow checker will understand; some people can get frustrated when they want to write a valid program that gets rejected, but this is going to be the case with any kind of static analysis.

Re: Why Rust for Low-Level Linux Programming?

#14

Post by PeCaN »

frankmcsherry wrote: post #7
Scarbutt wrote: post #2

Rust reduces the amount of state I need to keep track of in my brain. I doubt it, the mental overhead of doing "safe memory programming" in Rust is very high. Edit: all good replies, want to clarify and forgot to mention that I was comparing to languages with a GC, since I'm seeing Rust being used for lots of stuff, in a general purpose programming language sense (like creating web frameworks for example). Also, for…

Not my experience, fwiw. Rust does a great job of handling the mental overhead (am I allowed to mutate this? who owns this? what is the contract for that?) for me.

Exactly. Compiler-enforced ownership and lifetimes _dramatically_ reduces the mental overhead of memory management compared to C. It also saves time from having to run things under Valgrind and ASAN just to make sure I didn't mess up. The extra time spent getting Rust code to compile is considerably shorter than the time required to debug something Valgrind found.

Re: Why Rust for Low-Level Linux Programming?

#15

Post by ktamura »

Bromskloss wrote: post #8
ktamura wrote: post #4

As a long-time developer marketing person, I must say Rust is kicking ass, not just as a language but as a community. They are deeply strategic. 1. Clear audience target: They aren't going after C++ gurus or C magicians but people who are new to systems programming. From Klabnik to Katz to literally everyone in the community, they are consistent with this messaging. 2. As part of 1, they have invested a lot in teachi…

> developer marketing person What is that? > They aren't going after C++ gurus or C magicians Don't they have anything to gain from using Rust?

Developer marketing: marketing to developers. Marketing gets a bad reputation among developers, but it's vital for any technology to be marketed: keeping documentation up to date, answering questions for newcomers, explaining strengths/weaknesses, etc.

>Don't they have anything to gain from using Rust?

Who's "they"?

Re: Why Rust for Low-Level Linux Programming?

#16

Post by steveklabnik »

TheMagicHorsey wrote: post #11

Is there any reason why embedded software for autonomous vehicles is still being written in C/C++? This last week I was talking to a friend at a company that makes a small autonomous vehicle. During testing their prototype suddenly went off in a straight line. They had to pull a safety to halt the vehicle or it would have gone straight forever into the Pacific Ocean. Turns out there was an unsafe access to a variable…

There's two reasons Rust might not be ready here yet. First, while LLVM supports a wide number of platforms, some embedded devices literally only support the exact version of the C compiler they ship to you, sometimes, it's even got its own custom patches. Second, we sort of assume 32 bits at the lowest, though we have a patch in the queue that starts some work on 8/16 bit support. This means some tiny micros are out of reach at the moment.

Re: Why Rust for Low-Level Linux Programming?

#17

Post by tiglionabbit »

ktamura wrote: post #15
Bromskloss wrote: post #8

Earlier quoted context omitted.

> developer marketing person What is that? > They aren't going after C++ gurus or C magicians Don't they have anything to gain from using Rust?

Developer marketing: marketing to developers. Marketing gets a bad reputation among developers, but it's vital for any technology to be marketed: keeping documentation up to date, answering questions for newcomers, explaining strengths/weaknesses, etc. >Don't they have anything to gain from using Rust? Who's "they"?

The magicians.

Re: Why Rust for Low-Level Linux Programming?

#18

Post by steveklabnik »

ktamura wrote: post #4

As a long-time developer marketing person, I must say Rust is kicking ass, not just as a language but as a community. They are deeply strategic. 1. Clear audience target: They aren't going after C++ gurus or C magicians but people who are new to systems programming. From Klabnik to Katz to literally everyone in the community, they are consistent with this messaging. 2. As part of 1, they have invested a lot in teachi…

Thanks! To be clear, I do very much want C and C++ programmers to be using Rust as well, I just think there's a lot of opportunity in the "new to systems" group. They're also just my group of people, so I find it easier to pitch things to them. I can talk about anything Ruby at any level with a Ruby person, but I first picked up C++ in the late 90s, and hadn't been active in systems-level stuff for a long time when I came to Rust, so I'm a bit removed from feeling their pains directly.

Re: Why Rust for Low-Level Linux Programming?

#19

Post by gue5t »

ktamura wrote: post #4

As a long-time developer marketing person, I must say Rust is kicking ass, not just as a language but as a community. They are deeply strategic. 1. Clear audience target: They aren't going after C++ gurus or C magicians but people who are new to systems programming. From Klabnik to Katz to literally everyone in the community, they are consistent with this messaging. 2. As part of 1, they have invested a lot in teachi…

As a C magician, I haven't written a new C project since the Rust 0.8 era. The only reason you would is ease of updating dependencies through distro package managers (because Rust has no stable ABI and performs extensive cross-library inlining). There's no need to market to C people because those who understand the language well will immediately get why Rust is better.

For C++ people, Rust's generics remain less powerful than template metaprogramming (which is Turing-complete, with people building real programs in the tarpit), so there are reasons you might not switch.

Meanwhile, Rust does make it a lot easier to get started with systems programming, which is good! Every tool should help both empower beginners and extend the reach of experts. For example, writing zero-copy parsers in C is fairly hard to get right, and might not be worth the debugging or validation time that even an expert might have to put in. C string manipulation works, but it's verbose and fiddly. In Rust, it's trivial to use the lifetime system to make sure you keep all the input data around long enough and don't read outside the buffer. You could even use #[must_use] and affine types to check that every character of input data ends up attributed to exactly one terminal.

Re: Why Rust for Low-Level Linux Programming?

#20

Post by pjmlp »

Bromskloss wrote: post #8
ktamura wrote: post #4

As a long-time developer marketing person, I must say Rust is kicking ass, not just as a language but as a community. They are deeply strategic. 1. Clear audience target: They aren't going after C++ gurus or C magicians but people who are new to systems programming. From Klabnik to Katz to literally everyone in the community, they are consistent with this messaging. 2. As part of 1, they have invested a lot in teachi…

> developer marketing person What is that? > They aren't going after C++ gurus or C magicians Don't they have anything to gain from using Rust?

A developer evangelist. Think someone doing a talk about new Java 9 features at a Java conference.

C++ gurus and C magicians already have invested too deep into their languages to throw everything away and start from zero.

For example I love Rust and play occasionally with it, but for the time being C++ is my native language on the job when I need to use a native language outside .NET or JVM.

I know it since the C++ARM "standard" and we depend on standard OS tooling that Rust is still catching up with.

The day will come when our customers will be able to do mixed debugging between JVM/.NET and Rust. Or produce COM as easy as C++ compilers do.

But these are things that beginners in systems programming aren't usually doing.

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