facebook/zstd

IBM Linux on z SIMD optimization

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#2,679 opened on May 21, 2021

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Description

Is your feature request related to a problem? Please describe. IBM z architecture provides SIMD capabilities that can be utilized for zstd optimization similar to SSE and Neon SIMD optimizations that have been contributrd to zstd.

Describe the solution you'd like Optimize zstd to utilize IBMz VX SIMD intrinsics in zstd_lazy.c and ztsd_compress.c equivalent to optimization for SSE and Neon.

Describe alternatives you've considered Because zstd has implemented architecture-specific optimizations for other architectures, a hand-coded implementation has been shown to provide unique benefits above auto-vectorization.

Additional context Financial bounty from IBM available for negotiation. Inquiries from interested developers welcome.

Contributor guide

Research direction
Study the existing SSE and Neon SIMD implementations in zstd (e.g., in zstd lazy.c and zstd compress.c) and adapt them to IBM z VX SIMD intrinsics, following the same optimization patterns.
Tech stack
c
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
CSIMD conceptszstd internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30