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Motivation

Weight prefetching could speedup model inference on NPU

Modifications

Move weight prefetch configuration to model loader for unification between different models to support weight prefetching on any model

Accuracy Tests

Benchmarking and Profiling

Checklist

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Summary of Changes

Hello @terfendail, 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 refactors the MLP weight prefetching mechanism, consolidating the NPU-specific prefetching logic into the model loader. This change aims to provide a unified and generic approach to weight prefetching across various models, enhancing NPU inference performance and simplifying future model integrations. It also introduces a new configuration option to control this feature.

Highlights

  • Unified MLP Weight Prefetching: The logic for MLP weight prefetching on NPU has been centralized within the model loader, allowing for a consistent approach across different models.
  • Model-Specific Prefetching Removal: NPU-specific weight caching and stream waiting logic has been removed from the Qwen3 model, as it is now handled generically by the model loader.
  • New Configuration Option: A new server argument, --enable-weights-prefetching, has been introduced to allow users to enable or disable this feature.

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Code Review

This pull request refactors the MLP weight prefetching logic for NPUs by centralizing it in the model loader. This is a good architectural improvement, promoting code reuse and simplifying model-specific implementations. The changes in qwen3.py correctly remove the now-redundant local prefetching logic, and the new server argument is added cleanly.

My review focuses on the new implementation in loader.py. I've identified a critical bug in how attributes are accessed and some opportunities to improve code clarity and maintainability. Specifically, there's a typo using a non-existent method, some commented-out code that should be removed, and a suggestion to make the MLP layer name configuration more robust.

Comment on lines 301 to 309
def mlpwrap(fwd):
@wraps(fwd)
def mlpwrapper(*args, **kwds):
fwdres = fwd(*args, **kwds)
if _is_npu and get_cmo_stream():
wait_cmo_stream()
return fwdres
return mlpwrapper
lmlp.forward = mlpwrap(lmlp.forward)
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medium

The use of a nested function mlpwrap to create the mlpwrapper decorator is a bit verbose and can be simplified for better readability. You can achieve the same result more directly by capturing the original forward method and then defining and assigning the wrapper.

Suggested change
def mlpwrap(fwd):
@wraps(fwd)
def mlpwrapper(*args, **kwds):
fwdres = fwd(*args, **kwds)
if _is_npu and get_cmo_stream():
wait_cmo_stream()
return fwdres
return mlpwrapper
lmlp.forward = mlpwrap(lmlp.forward)
original_forward = lmlp.forward
@wraps(original_forward)
def mlp_wrapper(*args, **kwds):
result = original_forward(*args, **kwds)
if _is_npu and get_cmo_stream():
wait_cmo_stream()
return result
lmlp.forward = mlp_wrapper

terfendail and others added 3 commits December 19, 2025 18:12
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
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2 participants