simdjson
json
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simdjson | json | |
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63 | 11 | |
18,337 | 412 | |
1.1% | 1.2% | |
9.2 | 8.7 | |
9 days ago | 3 days ago | |
C++ | C++ | |
Apache License 2.0 | Boost Software License 1.0 |
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simdjson
- 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?
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Any fresh jvm21 benchmarks ?
I expect a lot of transcoders will be rewritten when the Vector instructions land. You can see speedups when used in other languages, such as simdjson. Please try to be more thoughtful and not disregard other people's hard work so easily.
json
- Upcoming talk by Bjarne Stroustrup "What is good C++ code?" Nov 15, 2022
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New, fastest JSON library for C++20
Shouldn't your benchmark use a somewhat larger JSON? Something from https://github.com/boostorg/json/tree/develop/bench/data, for instance.
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- Newbie: "I want to contribute to the Boost [...] It will be really helpful if any mentor can guide me [...]" - Boost Pro: "Well, the first thing you should do is STAR this repository"
The mascot for the library appears to be Jason Voorhees. Should I be concerned?
- Google Protobuf vs JSON vs [insert candidate here]
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JSON for Modern C++ version 3.10.0
You should be able to build and include boost json as a standalone subproject in CMake if you are using C++17. (Or also possible to use as header only lib)
It gets far more complicated with C++11, since you also need a ton of other boost modules there.
For more Details you can read the Readme of it. https://github.com/boostorg/json
- Poifect: Perfect Hashing Library
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Where had Singletons gone from game engines?
https://github.com/boostorg/json/blob/f55bd4b85edd9b9b9b2d27fb49d66a990aa89001/include/boost/json/impl/object.hpp#L39
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Visual Studio's Natvis Debugging Framework Tutorial
I'm gonna throw this out there - Boost.JSON comes with .natvis visualizers for all of its data structures, so you can inspect all of its types in the debugger and get nice insights: https://github.com/boostorg/json/blob/932b97e5ce899f3faebb7b7ab5a68b023131b77f/include/boost/json/json.natvis
What are some alternatives?
RapidJSON - A fast JSON parser/generator for C++ with both SAX/DOM style API
json-schema-validator - JSON schema validator for JSON for Modern C++
jsoniter - jsoniter (json-iterator) is fast and flexible JSON parser available in Java and Go
cereal - A C++11 library for serialization
json - JSON for Modern C++
Cap'n Proto - Cap'n Proto serialization/RPC system - core tools and C++ library
slang - SystemVerilog compiler and language services
JsonCpp - A C++ library for interacting with JSON.
tiny-utf8 - Unicode (UTF-8) capable std::string
sonic - A blazingly fast JSON serializing & deserializing library
glaze - Extremely fast, in memory, JSON and interface library for modern C++