[Cherry-Pick][Optimization] merge matmul and add(#6986)

[BingooYang]

Motivation

性能优化

Modifications

将UnquantizedLinearMethod中的matmul和add用linear替换。
带bias情况基本上有加速，不带bias情况小shape下性能有下降（主要是python层if等调度开销，linear内部实现也是matmul）。

Usage or Command

无

Accuracy Tests

精度保持一致

Checklist

• [ x ] Add at least a tag in the PR title.
  • Tag list: [[FDConfig],[APIServer],[Engine], [Scheduler], [PD Disaggregation], [Executor], [Graph Optimization], [Speculative Decoding], [RL], [Models], [Quantization], [Loader], [OP], [KVCache], [DataProcessor], [BugFix], [Docs], [CI], [Optimization], [Feature], [Benchmark], [Others], [XPU], [HPU], [GCU], [DCU], [Iluvatar], [Metax]]
  • You can add new tags based on the PR content, but the semantics must be clear.
• [ x ] Format your code, run pre-commit before commit.
• [ x ] Add unit tests. Please write the reason in this PR if no unit tests.
• [ x ] Provide accuracy results.
• [ x ] If the current PR is submitting to the release branch, make sure the PR has been submitted to the develop branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

[paddle-bot]

Thanks for your contribution!

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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[fastdeploy-bot]

🤖 AI Code Review | 2026-04-03 17:30 CST

📋 Review 摘要

PR 概述：将 UnquantizedLinearMethod.apply() 中的 matmul + add 替换为 paddle.nn.functional.linear，优化带 bias 场景的计算性能

变更范围：model_executor/layers/linear.py（核心优化）、tests/e2e/utils/（测试 baseline 路径更新）

影响面 Tag：OP

问题

级别	文件	概述
🟡 建议	rollout_routing_replay_test_utils.py:160	baseline 路径硬编码日期 0403，建议语义化命名

总体评价

核心优化逻辑正确，新增的 bias 维度 assert 检查增强了代码健壮性。测试文件的 baseline 路径变更建议改用更语义化的版本命名方式。

[fastdeploy-bot]

🟡 建议 baseline 路径中硬编码了日期 0403。

这种命名方式可能导致未来维护困难：

1. 每次更新 baseline 都需要修改代码中的路径
2. 日期含义不够清晰，dev_uint8_0403 中的 0403 指的是什么不明确

建议：

1. 使用更语义化的版本命名，如 R3_BaseLine_v2.5_uint8
2. 或者将 baseline 路径配置化，通过环境变量或配置文件管理