SortingNetworks VS tock

On a side-note: I did an experiment to see whether C# could match C++ for vector-intensive computing: https://github.com/zvrba/SortingNetworks

Here's a concrete example of using pointers to access raw array memory and use SIMD intrinsics: https://github.com/zvrba/SortingNetworks

And now, for the fun of it, you can try with sorting. I've already done the hard work in C# (AVX2 intrinsics): https://github.com/zvrba/SortingNetworks

> I can't read C#

Not much different than C++...

> Do you generate the sorting network at compile time

No, except for power of two sizes up to 32. I experimented with run-time code generation (and compilation) for given sizes, but... the generated machine code has too long prologue and epilogue for that to be worth-while (though the sorting code itself is well optimized, as if directly compiled from source). That's also mentioned in "Benchmarks" section.

> What's your sorting network template?

See References.

> And probably related: how is vectorization used?

See the code. There's no template, the code is fully "dynamic" and adapts itself to array size. As for vectorization... it compares/swaps 8 ints/floats at once, with some swizzles to rearrange the elements. For sizes that are not power of 2, I use masked loads and stores and some extra logic for deciding which comparisons to skip. (I treat non-existing elements "as if" they were set to intmax or float infinity.)

This file https://github.com/zvrba/SortingNetworks/blob/master/Sorting... has it all.

> this week-end project

Sorry, can't read Rust. (Though it reminds me of days spent coding in Perl.) Most networks are not SIMD-friendly and the code as it's now is the 3rd iteration where I figured out how to best leverage SIMD to exploit the recursiveness and regularity in the network. (Not the least, no random memory accesses: only forward and backward loads and stores.)

Without SIMD, I don't think it'll be worth it, because network will also access the memory randomly (just as "standard" sort), and in addition it has worse algorithmic complexity.

So recently I posted a link with code for fast sorting of int arrays. People wondered how they'd perform for large arrays (1M elements), and I conjectured they'd be way slower because of their algorithmic complexity. Turns out I was wrong, they're 3-6x faster for arrays of length up to 1M elements. Updated code and benchmarks are now available at https://github.com/zvrba/SortingNetworks

The code (MIT license) is available here: https://github.com/zvrba/SortingNetworks

Hi! This is Daniel from OxidOS Automotive (stating this for disclaimer purposes).

Yes, our OS is based on TockOS, and our CEO (Alex Radovici) is #7 in the contributors list (https://github.com/tock/tock/graphs/contributors), with other colleagues contributing in the past years.

I'm definitely not the best person to answer this, but honestly it's not bad. Here's an example of a moderately complex peripheral, the cortex-m MPU, and how one rust OS handles it:

https://github.com/tock/tock/blob/3a0527d586702b8ae8cb242391...

Reads and writes turn into volatile reads, so everything works out under the hood. You get the benefits of everything having good names, declared sizes, and proper typing on your register accesses. You can extend that to bit accesses as well.

Rust still has a few areas it isn't competitive in, like your hyper limited or obscure chips (e.g. 8051s, XAP), mature tooling around formal methods, and a certification story for safety critical code. People are working on these latter two issues (e.g. ferrocene) and supposedly very close to public delivery, but you know how slow the industry is to adopt new things even then.

There's Tock (https://www.tockos.org/), which is written in Rust (with sprinkles of assembly).

Yeah, and I like I mentioned in the earlier comment, omitting the frame pointer reduces code size by 10% on RISC-V targets, which is huge when dealing with embedded flash: https://github.com/tock/tock/pull/1660

Tock is an excellent embedded OS written in Rust and has some good industrial support. I think Tock gets a lot of stuff right and I highly recommend some of the talks the developers gave on it.

Unfortunately, it increases the code size by 10%. I was looking into this just last week, and can confirm that it's still a problem on the latest version of Rust nightly: https://github.com/tock/tock/pull/1660

I wish we could have frame pointers, because they would make working in embedded land so much easier and more reliable, but a 10% increase in code size just isn't worth it.

TockOS was the first rust RTOS I found. Coincidentally, it has had support for the esp32c3 for over a year now.