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?

Personal Statement on AI Risk

Linux development is benefiting from AI, but not from its coding

I joined the 'anti-chatbox' interface movement, and build Moe because of it

Show HN: Airmash – HTML5 Multiplayer Missile Warfare

Show HN: Kaflow Search – A desktop tool for locally indexed Kafka message search

Benchmark Llamacpp on Intel Panther Lake: Vulkan vs. SYCL vs. OpenVINO vs. CPU

Building agents? Here is everything you need to know in one long-read

Show HN: Sloptris - If Tetris was like AI-assisted dev

OpenAI Considers Pre-IPO Funding Round at More Than $1.2T Valuation

Scaling Golang CI by Replacing actions/setup-go

Show HN: Picxel – Turn reference images into pixel-art game assets

Show HN: How Stale Is Your AI? Release age and training cutoff for 20 models

ImpactGate: A merge gate that scores the structural decay AI adds

Voyager – defense revenue as a patience subsidy for commercial space station bet

Corporate and political systems are efficient filters to promote psychopaths

Why do people hold vacant land out of use?

Operating System powered by Qwen 3.8 27B at 1950 tokens/SEC

Fujifilm Launches Palm-Top Size Camera Instax Pal 2 for $170

Robert Kraft – Epstein friend bans Macklemore

How Electric Cars Took Hold in Australia

Browser Automation Skill from Tencent

Paying for frontier AI models buys 4-month head start at 5x the cost

Useful Abstractions

My Dumbphone Made My Life Better. It Made Everyone Else's Worse

Residential proxies as the next front in the AI wars

Show HN: Calmscroll – A Library of Paragraphs

Is METR a Meaningful Check on Anthropic?

Altman: "I'm on Team Human" (Interview)

SK Hynix in talks with Intel about deal to make memory chips in US

Can an Agent Port a Codebase?