kobzol

7 ms·

1.
by kobzol 1y ago
The new Zig I/O idea seems like a pretty ingenious idea, if you write mostly applications and don't need stackless coroutines. I suspect that writing libraries using this style will be quite error-prone, because library authors wi
2.
by kobzol 1y ago
I also don't know all the details, but the Rust parser tokens contain horrible crimes, primarily because of macros. All I wanted to say was that applying DoD to the parser in Rust would (IMO) be much more difficult than in Zig, because
3.
by kobzol 1y ago
I don't think we hit a bedrock. As I wrote, we have a lot of ideas for massive improvements. But we need more people to work on them.
4.
by kobzol 1y ago
I'm not sure how that works. You either let the compiler compile your whole program with AVX (which duplicates the binary) or you manually use AVX with runtime detection on selected places (which requires writing manual vectorization).
5.
by kobzol 1y ago
You have a fair point, I agree that while compiler performance is a priority, is is one of many priorities, and not currently super high on the list for many Rust Project developers. I wish it was different, but the only thing we can do is
6.
by kobzol 1y ago
For many use-cases yes, but there are crates bottlenecked on different things than the codegen backend. But I don't think that's the point. We could get rid of LLVM and use other backends, same as we could do other improvements. T
7.
by kobzol 1y ago
I think a reasonable comparison would have to be DoD Rust parser vs current Rust parser. Comparing across languages isn't very useful, because Zig has very different syntax rules, and doesn't provide diagnostics near the same leve
8.
by kobzol 1y ago
Great post! I have some random guesses as to why the 40% vs 60-70% memory issues percentage: - 180k is not that much code. The 60-70% number comes from Google and Microsoft, and they are dealing with way larger codebases. Of course, the s
9.
by kobzol 1y ago
That didn't even occur to me, tbh :) But it doesn't have to be SQL linting, I just wanted to appreciate the mindset of not being lazy/afraid to write an unorthodox test.
10.
by kobzol 1y ago
If I only insert data into the DB once, I could miss important states. Like, I could add non-NULL data to a NOT NULL column, then make it NULL, and then make it NOT NULL again. If I don't insert NULL into the column in-between the last
11.
by kobzol 1y ago
If you're writing applications or tests, it's mostly the simpler kind of code. If you're writing reusable (or perf. critical code), you will start seeing generics and lifetimes much more often.
12.
by kobzol 1y ago
(author of the post) Just to clarify a bit, the test ofc isn't a fully general solution to solving issues with database migrations (I hinted what that might be in the blog post), although it's still useful to provide a nice error
13.
by kobzol 1y ago
I don't really see an attack surface for a dev dependency.
14.
by kobzol 2y ago
Yeah by user space I just meant without root, sorry. HQ runs on supercomputers where the environment is heavily locked up, even Docker doesn't work. I think that PID namespaces aren't really possible, but I haven't tried it y
15.
by kobzol 2y ago
Could be done, yeah, but 20s isn't that much, and I'd like to avoid adding more test-only magic environment variables zo configure this (our end-to-end tests are in Python and they use HQ as a binary).
16.
by kobzol 2y ago
It is sadly not propagated to grandchildren. I tries the subreaper approach, but it doesn't help. The children are reparented to the worker, but when the worker dies, they are then just reparented to init, like normally.
17.
by kobzol 2y ago
I do use setsid when spawning the children (I omitted it from the post, but I set it in the dsme pre_exec call where I configure DEATHSIG) but they don't receive any signal, IIRC. Or if they do, it does not seem to be propagated to the
18.
by kobzol 2y ago
The stdlib already mostly does all of that :) Check out https://kobzol.github.io/rust/2024/01/28/process-spawning-pe... .
19.
by kobzol 2y ago
That's a very good point! But yeah, we use the single threaded runtime, so this shouldn't be a concern.
20.
by kobzol 2y ago
The Rust bhild config defaults are pretty fine for the general case. It's just that not everyone has the general case :) In Rust the normal distribution will be quite flattened.
21.
by kobzol 3y ago
Yeah, I actually generated these small charts out of a flamegraph, because it contains too much information and isn't easily split into three distinct parts. And once you condense the information into just 3 blocks, then using a flameg
22.
by kobzol 3y ago
There have been some recent improvements to this, but yeah, it can be still quite large. There is a WIP development of a garbage collector in Cargo that could help with this.
23.
by kobzol 3y ago
It didn't really require establishing a working group :) That is just an effort to improve Rust binary sizes in general. In the end, changes in Rust can take a very long time (years) sometimes. It's maintained and developed by vol
24.
by kobzol 3y ago
There is some work underway to enable removing the backtrace generation/parsing from Rust binaries. It's hardcoded for now though.
25.
by kobzol 3y ago
You can't really use dead code elimination on debug symbols, because you don't know which symbols will you need. You would need to know where and how will your program crash or if the user will want to use a debugger on it.
26.
by kobzol 3y ago
I have implemented the fix and got it approved in the span of about 3 weeks (and that was over the Christmas!). Doesn't seem that bad to me, given that it's a change that will affect pretty much any Rust user by default.
27.
by kobzol 3y ago
Mostly the formatting machinery from stdlib. You can go sub 100 KiB or even less without it, but unless you target embedded, there's really a reason to do that, IMO.
28.
by kobzol 3y ago
Rust supports linker plugin LTO ( https://doc.rust-lang.org/rustc/linker-plugin-lto.html ).
29.
by kobzol 3y ago
I have used Python for 10+ years, and I'm able to forget what are the input arguments/return type of a function after 30 minutes of working on some other part of the code :)
30.
by kobzol 3y ago
I don't think that it's a good idea in general to inherit the construction functions. But if you wanted to do that, classmethod is the way to go, of course.

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