Packed Data Support in Haskell

https://arthi-chaud.github.io/posts/packed/

77•matt_d•1y ago

Comments

nine_k•1y ago

> Introducing the ‘packed’ data format, a binary format that allows using data as it is, without the need for a deserialisation step. A notable perk of this format is that traversals on packed trees is proven to be faster than on ‘unpacked’ trees: as the fields of data structures are inlines, there are no pointer jumps, thus making the most of the L1 cache.

That is, a "memory dump -> zero-copy memory read" of a subgraph of Haskell objects, allowing to pass such trees / subgraphs directly over a network. Slightly reminiscent of Cap'n Proto.

90s_dev•1y ago

We are always reinventing wheels. If we didn't, they'd all still be made of wood.

Zolomon•1y ago

They mention this in the article.

spockz•1y ago

It reminds me more of flat buffers though. Does protobuf also have zero allocation (beyond initial ingestion) and no pointer jumps?

cstrahan•1y ago

No, one example of why being variable sized integers.

See https://protobuf.dev/programming-guides/encoding/

carterschonwald•1y ago

One thing that sometimes gets tricky in these things is handling Sub term sharing. I wonder how they implemented it.

tlb•1y ago

> the serialised version of the data is usually bigger than its in-memory representation

I don’t think this is common. Perhaps for arrays of floats serialized as JSON or something. But I can’t think of a case where binary serialization is bigger. Data types like maps are necessarily larger in memory to support fast lookup and mutability.

nine_k•1y ago

I suppose all self-describing formats, like protobuf, or thrift or, well, JSON are bigger than the efficient machine representation, because they carry the schema in every message, one way or another.

IsTom•1y ago

If you use a lot of sharing in immutable data it can grow a lot when serializing. A simple pathological example would be a tree that has all left subtrees same as the right ones. It takes O(height) space in memory, but O(2^height) when serialized.

gitroom•1y ago

honestly i wish more stuff worked this way - fewer hops in memory always makes me happy

lordleft•1y ago

This was very well written. Excellent article!

NetOpWibby•1y ago

Is this like MessagePack for Haskell?

AWS Lambda Web Functions

The First Social Network

They War-Gamed Dimming the Sun. It Went Worse Than You Think

NASA may have proof life once existed on Mars

Lever House

Voyager Earth – animated travel route maps rendered in the browser

The Tetrad Tour, Part III: Why AI Needs Its Linnaeus

An Industrial Policy for Drones

Neocloud Endgame

Empirical Computation: Prompting versus Programming [pdf]

Japan declares a "state of emergency in cyberspace" as cyberattacks surge

Claude Notify – Desktop Notifications for Claude Code on Windows

Portless: Vercel Labs Replaces Localhost Ports with Named URLs

Ukraine strikes didn't blow up Russian disinformation on social

Breaking Bad star RJ Mitte dies aged 34

RenkuOS (A Fork of Haiku)

What I've been seeing lately

Adm Programming Language

Patching Zig's Std

UK data centre giant removed evidence of China deal ahead of $35B listing

What the Greeks Would Call Our Government [video]

Orion2re: A restoration effort for the Master of Orion II game engine

AI's mathematics blitz pushes science into new territory

Agentic BSS Explained: AI-Native Model, Architecture and Use Cases [pdf]

Janas: Run LLMs larger than RAM by streaming experts from SSD

The CEO's of Broadcom and Intel Say the Quiet Part Out Loud about AI and ROI

Making DNA: The Quest for Synthetic Life (2023)

Mozilla Welcomes Raffi Krikorian as Chief Technology Officer

Artificial Intelligence in the Firm: Bottlenecks in Software Production [pdf]

Using Jev to make your agents write the code and design the app the way you do