EA Standard Template Library VS simdjson

> you can still use it with smart pointers provided by any other library

Is the point of having a kitchen-sink library like this not that you dont have to reach for a 3rdparty library for things that you need 'all the time'?

Certainly, not everyone needs it.

...but, not everyone needs threads either. Not everyone needs an http server; and yet, if you have an application framework that provides them, when you do need them, it saves you reaching for yet-another-dependency.

Was that no the point from the beginning?

unique_ptr is a fundamental primitive for many, as you see from some other frameworks (1), and implementation is not always either a) trivial, or b) as simple as 'just use std::unique_ptr'.

This does seem like a very opinionated decision with reasonably unclear justification.

[1] - eg. https://github.com/EpicGames/UnrealEngine/blob/release/Engin..., https://github.com/electronicarts/EASTL/blob/master/include/...

Can I introduce you to EASTL

For games focused stuff have a look at EASTL https://github.com/electronicarts/EASTL also perhaps some of the Data Oriented Design stuff (see Mike Acton's CPP Con Talks). This also have loads of good stuff https://www.dataorienteddesign.com/dodbook/

C++, but generally treat it as C. STL is pretty slow while debugging so we avoid it and write our own replacements. If you don't want to drive that deep use something like EASTL: https://github.com/electronicarts/EASTL

In my experience game devs don't eschew the STL because of compile times, but because (a) its memory management is not sufficiently tunable and (b) it uses exceptions heavily which many game engines disable entirely due to perceived performance problems. For this reason, some of the engines I've worked on have used their own forks of the STL in the spirit of EASTL to rectify these issues. Others like my current project just don't use the STL at all (outside of some third-party library code) and use custom libraries for everything.

In my opinion, you should also benchmark it against something like boost::container::flat_set or eastl::vector_set and you should expect the same performance as with your ordered functionality. Another interesting idea for organization of such flat and sorted container can be found here.

finally, if you're worried about performance (a lot of aspiring game programmers seem to be, even though for anything but high-end engines the STL is likely fine if you know what you're doing..) you could look into the EA STL or other STL replacements..

check it out: https://github.com/electronicarts/EASTL

I just took a look at their atomic.h and wow, "well-documented" is an understatement !

It's also supported by simdjson [0] (which has a lot of language bindings [1]):

> Multithreaded processing of gigantic Newline-Delimited JSON (ndjson) and related formats at 3.5 GB/s

[0] https://simdjson.org/

[0] https://github.com/simdjson/simdjson?tab=readme-ov-file#bind...

String parsing is negligible compared to the speed of the DOM which is glacially slow: https://news.ycombinator.com/item?id=38835920

Come on, people, make an effort to learn how insanely fast computers are, and how insanely inefficient our software is.

String parsing can be done at gigabytes per second: https://github.com/simdjson/simdjson If you think that is the slowest operation in the browser, please find some resources that talk about what is actually happening in the browser?

Thanks for all the detailed information! That answers a bunch of my questions and the implementation of strlen is nice.

The instruction I was thinking of is pshufb. An example ‘weird’ use can be found for detecting white space in simdjson: https://github.com/simdjson/simdjson/blob/24b44309fb52c3e2c5...

This works as follows:

1. Observe that each ascii whitespace character ends with a different nibble.

2. Make some vector of 16 bytes which has the white space character whose final nibble is the index of the byte, or some other character with a different final nibble from the byte (eg first element is space =0x20, next could be eg 0xff but not 0xf1 as that ends in the same nibble as index)

3. For each block where you want to find white space, compute pcmpeqb(pshufb(whitespace, input), input). The rules of pshufb mean (a) non-ascii (ie bit 7 set) characters go to 0 so will compare false, (b) other characters are replaced with an element of whitespace according to their last nibble so will compare equal only if they are that whitespace character.

I’m not sure how easy it would be to do such tricks with vgather.vv. In particular, the length of the input doesn’t matter (could be longer) but the length of white space must be 16 bytes. I’m not sure how the whole vlen stuff interacts with tricks like this where you (a) require certain fixed lengths and (b) may have different lengths for tables and input vectors. (and indeed there might just be better ways, eg you could imagine an operation with a 256-bit register where you permute some vector of bytes by sign-extending the nth bit of the 256-bit register into the result where the input byte is n).

Additionally, if you like low level stuff, check out libfmt (https://github.com/fmtlib/fmt) - not a big project, not difficult to understand. Or something like simdjson (https://github.com/simdjson/simdjson).

Everything you said is totally reasonable. I'm a big fan of napkin math and theoretical upper bounds on performance.

simdjson (https://github.com/simdjson/simdjson) claims to fully parse JSON on the order of 3 GB/sec. Which is faster than OP's Go whitespace parsing! These tests are running on different hardware so it's not apples-to-apples.

The phrase "cannot go faster than this" is just begging for a "well ackshully". Which I hate to do. But the fact that there is an existence proof of Problem A running faster in C++ SIMD than OP's Probably B scalar Go is quite interesting and worth calling out imho. But I admit it doesn't change the rest of the post.

I have same question as /u/JDRiverRun : how do you deal with JSON, do you parse json on Rust side or on Emacs side. I see that you are requiring json.el in your lspce.el, but I haven't looked through entire file carefully. If you parse on Rust side, do you use simdjson (there are at least two Rust bindings to it)? If yes, what are your impressions, experiences compared to more "standard" json library?