simdjson
llvm-project
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simdjson | llvm-project | |
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65 | 349 | |
18,362 | 25,451 | |
1.2% | 3.6% | |
9.2 | 10.0 | |
15 days ago | 6 days ago | |
C++ | C++ | |
Apache License 2.0 | GNU General Public License v3.0 or later |
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simdjson
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Tips on adding JSON output to your command line utility. (2021)
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...
- 1BRC Merykitty's Magic SWAR: 8 Lines of Code Explained in 3k Words
- Training great LLMs from ground zero in the wilderness as a startup
- simdjson: Parsing Gigabytes of JSON per Second
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Use any web browser as GUI, with Zig in the back end and HTML5 in the front end
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?
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Cray-1 performance vs. modern CPUs
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).
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Codebases to read
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).
- Simdjson: Parsing Gigabytes of JSON per Second
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Building a high performance JSON parser
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.
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New package : lspce - a simple LSP Client for Emacs
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?
llvm-project
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Ask HN: Which books/resources to understand modern Assembler?
'Computer Architeture: A Quantitative Apporach" and/or more specific design types (mips, arm, etc) can be found under the Morgan Kaufmann Series in Computer Architeture and Design.
"Getting Started with LLVM Core Libraries: Get to Grips With Llvm Essentials and Use the Core Libraries to Build Advanced Tools "
"The Architecture of Open Source Applications (Volume 1) : LLVM" https://aosabook.org/en/v1/llvm.html
"Tourist Guide to LLVM source code" : https://blog.regehr.org/archives/1453
llvm home page : https://llvm.org/
llvm tutorial : https://llvm.org/docs/tutorial/
llvm reference : https://llvm.org/docs/LangRef.html
learn by examples : C source code to 'llvm' bitcode : https://stackoverflow.com/questions/9148890/how-to-make-clan...
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Flang-new: How to force arrays to be allocated on the heap?
See
https://github.com/llvm/llvm-project/issues/88344
https://fortran-lang.discourse.group/t/flang-new-how-to-forc...
- The LLVM Compiler Infrastructure
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Programming from Top to Bottom - Parsing
You can never mistake type_declaration with an identifier, otherwise the program will not work. Aside from that constraint, you are free to name them whatever you like, there is no one standard, and each parser has it own naming conventions, unless you are planning to use something like LLVM. If you are interested, you can see examples of naming in different language parsers in the AST Explorer.
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Look ma, I wrote a new JIT compiler for PostgreSQL
> There is one way to make the LLVM JIT compiler more usable, but I fear it’s going to take years to be implemented: being able to cache and reuse compiled queries.
Actually, it's implemented in LLVM for years :) https://github.com/llvm/llvm-project/commit/a98546ebcd2a692e...
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C++ Safety, in Context
> It's true, this was a CVE in Rust and not a CVE in C++, but only because C++ doesn't regard the issue as a problem at all. The problem definitely exists in C++, but it's not acknowledged as a problem, let alone fixed.
Can you find a link that substantiates your claim? You're throwing out some heavy accusations here that don't seem to match reality at all.
Case in point, this was fixed in both major C++ libraries:
https://github.com/gcc-mirror/gcc/commit/ebf6175464768983a2d...
https://github.com/llvm/llvm-project/commit/4f67a909902d8ab9...
So what C++ community refused to regard this as an issue and refused to fix it? Where is your supporting evidence for your claims?
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Clang accepts MSVC arguments and targets Windows if its binary is named clang-cl
For everyone else looking for the magic in this almost 7k lines monster, look at line 6610 [1].
[1] https://github.com/llvm/llvm-project/blob/8ec28af8eaff5acd0d...
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Rewrite the VP9 codec library in Rust
Through value tracking. It's actually LLVM that does this, GCC probably does it as well, so in theory explicit bounds checks in regular C code would also be removed by the compiler.
How it works exactly I don't know, and apparently it's so complex that it requires over 9000 lines of C++ to express:
https://github.com/llvm/llvm-project/blob/main/llvm/lib/Anal...
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Fortran 2023
https://github.com/llvm/llvm-project/blob/main/flang/docs/F2...
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MiniScript Ports
• Go • Rust • Lua • pure C (sans C++) • 6502 assembly • WebAssembly • compiler backends, like LLVM or Cranelift
What are some alternatives?
RapidJSON - A fast JSON parser/generator for C++ with both SAX/DOM style API
zig - General-purpose programming language and toolchain for maintaining robust, optimal, and reusable software.
jsoniter - jsoniter (json-iterator) is fast and flexible JSON parser available in Java and Go
Lark - Lark is a parsing toolkit for Python, built with a focus on ergonomics, performance and modularity.
json - JSON for Modern C++
gcc
json-schema-validator - JSON schema validator for JSON for Modern C++
SDL - Simple Directmedia Layer
JsonCpp - A C++ library for interacting with JSON.
cosmopolitan - build-once run-anywhere c library
json - A C++11 library for parsing and serializing JSON to and from a DOM container in memory.
windmill - Open-source developer platform to turn scripts into workflows and UIs. Fastest workflow engine (5x vs Airflow). Open-source alternative to Airplane and Retool.