58 lines
2.5 KiB
Python
58 lines
2.5 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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"""Declarative OffloadPlan for distributed layerwise offload.
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Models declare this as a class attribute ``_offload_plan`` on the
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pipeline class. When present, the offloader uses it instead of
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heuristic block discovery.
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"""
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from __future__ import annotations
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from dataclasses import dataclass, field
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from torch import nn
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@dataclass(frozen=True)
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class OffloadPlan:
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"""Optional declarative metadata for distributed layerwise offload.
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Models declare this as a class attribute ``_offload_plan`` on the
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pipeline class. When present, the offloader uses it instead of
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heuristic block discovery, making it easier to support new models
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without offload-specific logic in constructor or forward code.
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If not declared, the offloader falls back to:
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1. ``_layerwise_offload_blocks_attrs`` on each DiT module class.
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2. Heuristic search for ``layers`` / ``blocks`` / ``h`` attributes.
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Attributes:
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block_attrs: Maps DiT path → tuple of block-list attribute names.
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e.g. ``{"transformer": ("gen_layers",),
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"transformer.language_model": ("layers",)}``
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offload_submodules: Maps child name → block-list attribute name,
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for large non-DiT submodules within a DiT that should be
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independently offloaded with their own hooks.
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e.g. ``{"context_encoder": "layers"}``
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resident_dit_paths: DiT paths whose leading blocks may be kept on the
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device when ``dlo_resident_layers`` is nonzero. Keeping this
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model-declared avoids applying a consumer-GPU tuning knob to
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auxiliary or dual DiTs unintentionally.
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encoder_block_attrs: Maps encoder paths to rank-local block-list paths.
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These blocks are streamed with ordinary layerwise hooks, never
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with the DiT AllGather group.
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"""
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on_demand_component_paths: frozenset[str] = field(default_factory=frozenset)
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block_attrs: dict[str, tuple[str, ...]] = field(default_factory=dict)
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offload_submodules: dict[str, str] = field(default_factory=dict)
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resident_dit_paths: frozenset[str] = field(default_factory=frozenset)
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encoder_block_attrs: dict[str, tuple[str, ...]] = field(default_factory=dict)
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def get_offload_plan(pipeline: nn.Module) -> OffloadPlan | None:
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"""Retrieve the OffloadPlan declared by the pipeline, if any."""
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return getattr(pipeline, "_offload_plan", None)
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