RoaringBitmap / RoaringBitmap/roaring

Use vector instructions for union2by2

Open
#288 5 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

help wanted performance
Dominant language
Go
Stars
2.9k
Forks
262
Avg merge
2h 34m
Merged PRs (30d)
8

Description

We have ARM assembly for union2by2 as per https://github.com/RoaringBitmap/roaring/pull/287

It should be said that there are vectorized algorithm (hint: ARM NEON) for union routines. It appears in the C code (for SSE only but it is portable).

https://github.com/RoaringBitmap/CRoaring/blob/master/src/array_util.c#L1569-L1647

It is described in section 4.3 of the following paper:

It is actually not difficult to implement. For someone that is either fluent in ARM NEON or wants to learn... it is a great project.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the ARM assembly for union2by2 from pull request 287, then compare it with the vectorized union routines in CRoaring's src/array_util.c at lines 1569-1647 and section 4.3 of the referenced paper. The work is complete when union2by2 uses the corresponding ARM NEON approach while preserving the routine's union behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
go
Domain
performance
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.