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[2/n]decouple quantization implementation from vLLM dependency#8112

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zhyncs merged 21 commits intosgl-project:mainfrom
AniZpZ:gptq_kernel_refactor
Aug 14, 2025
Merged

[2/n]decouple quantization implementation from vLLM dependency#8112
zhyncs merged 21 commits intosgl-project:mainfrom
AniZpZ:gptq_kernel_refactor

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@AniZpZ AniZpZ commented Jul 17, 2025

Motivation

The primary goal of this change is to enhance the consistency and stability of SGLang's quantization features. By decoupling the quantization implementation from its vLLM dependency, we aim to make the module easier to maintain and more portable.
Full realization of this goal will involve several subsequent PRs; this particular PR addresses the marlin kernel issues.

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Co-authored-by: walker-ai <yiyun.wyt@antgroup.com>
Co-authored-by: yinfan98 <1106310035@qq.com>
@AniZpZ AniZpZ mentioned this pull request Jul 17, 2025
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Summary of Changes

Hello @AniZpZ, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the project's quantization capabilities by decoupling existing Marlin implementations from a specific Mixture of Experts dependency and introducing new, generalized GPTQ and Marlin GEMM kernels. This refactoring broadens the applicability of these optimized quantization techniques across the codebase, improving efficiency for various low-bit inference scenarios, including new support for FP4 quantization.

Highlights

  • Quantization Decoupling: Marlin-based quantization implementations (GPTQ, AWQ repack) are moved from a MoE-specific path (csrc/moe/marlin_moe_wna16) to a more general GEMM path (csrc/gemm/marlin), indicating a broader applicability beyond Mixture of Experts.
  • New GPTQ Kernels: Introduces comprehensive GPTQ GEMM kernels (2-bit, 3-bit, 4-bit, 8-bit) adapted from exllamav2 and GPTQ-for-LLaMa, including weight reconstruction and shuffling functionalities.
  • Marlin GEMM Integration: Integrates the core Marlin GEMM implementation, enabling highly optimized quantized matrix multiplication with support for various quantization types (INT4, INT8, FP4, FP8) and configurations (group size, act-order).
  • FP4 Quantization Support: Adds support for FP4 (E2M1) floating-point quantization, expanding the range of supported low-bit quantization schemes.
  • CUDA Utilities: Introduces new CUDA utility files for atomic operations on half types, matrix views for quantized data, and specialized quantization/dequantization (QDQ) functions for different bit-widths.
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Code Review

The pull request decouples the quantization implementation from the vLLM dependency. The changes involve adding new CUDA kernels for GPTQ and AWQ, refactoring existing code, and updating CMakeLists.txt. The code introduces new matrix view classes and implements dequantization and matrix multiplication kernels for different bit widths (2, 3, 4, and 8 bits). Additionally, it includes functions for shuffling and reconstructing quantized weights. The changes aim to provide a more modular and efficient implementation of quantization techniques.

@AniZpZ AniZpZ mentioned this pull request Jul 20, 2025
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@AniZpZ AniZpZ marked this pull request as ready for review July 25, 2025 04:42
@zhyncs zhyncs changed the title [WIP][2/n]decouple quantization implementation from vLLM dependency [2/n]decouple quantization implementation from vLLM dependency Jul 25, 2025
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zhyncs commented Aug 14, 2025

@AniZpZ @Hongbosherlock please fix the conflicts thanks

@zhyncs zhyncs merged commit 5aa1ebd into sgl-project:main Aug 14, 2025
4 of 57 checks passed
narutolhy pushed a commit to narutolhy/sglang that referenced this pull request Aug 17, 2025
…roject#8112)

Co-authored-by: walker-ai <yiyun.wyt@antgroup.com>
Co-authored-by: leoneo <1320612015@qq.com>
MahmoudAshraf97 pushed a commit to MahmoudAshraf97/sglang that referenced this pull request Sep 8, 2025
…roject#8112)

Co-authored-by: walker-ai <yiyun.wyt@antgroup.com>
Co-authored-by: leoneo <1320612015@qq.com>
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4 participants