[Performance] Add per-component DLO offload policy

Signed-off-by: hsliuustc0106 <liuhongsheng4@huawei.com>

docs/design/feature/offloader/distributed_layerwise_offload.md

@@ -29,6 +29,7 @@ Legend: ✅ supported, ⚠️ compatibility path or limited validation, ❌ unsu
 | **Other online quantization methods** | ❌ Rejected until runtime packing and scale layouts are validated. | ⚠️ Allowed through the ordinary loader; validation is method-specific. |
 | **Model-level or standard layerwise CPU offload** | ❌ Disabled because DLO takes priority. | ❌ Disabled because DLO takes priority. |
 | **Resident leading layers** | ❌ Rejected. | ✅ Requires eligible resident paths in the model's `OffloadPlan`. |
+| **Auxiliary component policy** | ✅ Encoders/VAEs may remain resident. | ✅ Encoders/VAEs may remain resident. |
 
 See [Parallelism compatibility](#parallelism-compatibility) and
 [Request and loading constraints](#request-and-loading-constraints) for the
@@ -419,6 +420,22 @@ failure.
 - **HSDP + DP or TP:** rejected independently by the diffusion parallel
   configuration.
 
+### Auxiliary component policy
+
+`dlo_offload_components` maps discovered encoder/VAE paths to booleans. A
+component set to `False` is materialized on the target device once and is not
+entered through the model's manual offload lifecycle. A `True` value permits
+the existing `OffloadPlan.on_demand_component_paths` and encoder block-hook
+behavior; it does not add support where the model declares none. The optional
+`default` key handles unmatched auxiliary components, and an empty map
+preserves the current policy.
+
+The policy is resolved after component discovery and before DLO mutates DiT
+storage. Unknown names, including DiT paths, are rejected. DLO continues to
+own DiT streaming regardless of this map, which avoids an invalid state where
+the loader has skipped ordinary DiT materialization but the backend is asked
+to keep that DiT resident.
+
 ## Request and loading constraints
 
 AllGather DP multi-concurrency requires:
@@ -430,6 +447,15 @@ AllGather DP multi-concurrency requires:
 The no-AllGather path does not impose these DLO-specific synchronized-wave
 requirements.
 
+MiniMax-H3 currently builds one global encoder TP group and broadcasts the
+resulting conditioning from global rank 0. Therefore an encoder TP group that
+spans multiple DP replicas is not valid for independent-prompt AllGather
+waves. Exact-recipe DP2/TP2 and DP2/SP2 experiments with encoder TP4 completed
+the collective schedule, but two distinct prompts with the same seed produced
+byte-identical video and audio in every measured wave. Enabling or disabling
+encoder offload produced paired-identical results, so this is a pre-existing
+model topology limitation rather than component-policy behavior.
+
 Direct checkpoint mmap can back either transfer path. It is currently limited
 to proven TP1, non-HSDP, non-online-quantized layouts. Other layouts use the
 ordinary loader. Per-tensor online FP8 linears can use DLO AllGather after the
@@ -494,6 +520,9 @@ AllGather, because DP replicas did not share checkpoint-backed runtime
 weights. This is a functional and memory smoke test, not a production-quality
 performance or output-quality benchmark.
 
+These B300 DP waves intentionally reused the same prompt and seed, so they do
+not establish independent-prompt isolation across DP replicas.
+
 ### Host-memory measurement
 
 A two-worker MiniMax-H3 FL2VA measurement on one L20X node compared the

docs/user_guide/diffusion/offloader/distributed_layerwise_offload.md

@@ -36,7 +36,8 @@ vllm serve /path/to/model --omni \
 vllm serve /path/to/model --omni \
   --enable-distributed-layerwise-offload \
   --data-parallel-size 4 \
-  --dlo-no-use-allgather
+  --dlo-no-use-allgather \
+  --dlo-offload-components '{"text_encoder": false}'
 
 # Sequence parallel deployment
 vllm serve /path/to/model --omni \
@@ -51,6 +52,7 @@ omni = Omni(
     model="/path/to/model",
     enable_distributed_layerwise_offload=True,
     dlo_use_allgather=True,
+    dlo_offload_components={"text_encoder": False},
 )
 ```
 
@@ -63,6 +65,7 @@ omni = Omni(
 | `--dlo-use-allgather` | Shard host weights and reconstruct with AllGather | `true` |
 | `--dlo-no-use-allgather` | Stream complete rank-local blocks without a DLO weight collective | `false` |
 | `--dlo-resident-layers N` | Keep N leading main-DiT blocks on device; requires no-AllGather and model-declared resident paths | `0` |
+| `--dlo-offload-components JSON` | Permit or disable offload for discovered encoder/VAE components | `{}` |
 | `--host-weight-runtime-mode {disabled,preferred,required}` | HWR policy: no interaction, populate on a miss, or require an exact hit | `disabled` |
 | `--host-weight-runtime-root PATH` | Writable node-local HWR store shared by workers in one storage domain; required for `preferred` and `required` | unset |
 | `--dlo-host-registration-limit-gib N` | Optional per-worker ceiling for registering an HWR mmap; zero adds no ceiling | `0` |
@@ -244,6 +247,25 @@ class MyPipeline(nn.Module):
 When no plan exists, discovery falls back to
 `_layerwise_offload_blocks_attrs` and then heuristic attribute lookup.
 
+## Auxiliary component policy
+
+`dlo_offload_components` follows the same component-map style as diffusion
+quantization. Keys are discovered encoder or VAE paths, values are booleans,
+and `default` is the optional fallback:
+
+```python
+dlo_offload_components = {
+    "text_encoder": False,
+    "default": True,
+}
+```
+
+`True` permits the model's existing DLO behavior for that component. `False`
+keeps the whole component resident, including its child blocks and non-block
+modules. An empty map preserves current behavior. Unknown keys are rejected;
+the map does not control DiT blocks because enabling DLO gives the backend
+ownership of DiT streaming.
+
 ## Data-parallel concurrency
 
 With `data_parallel_size > 1` and AllGather enabled, the scheduler can process
@@ -268,6 +290,13 @@ must enter each collective.
   are validated.
 - Resident leading layers require `--dlo-no-use-allgather` and a model
   `OffloadPlan` that declares eligible `resident_dit_paths`.
+- Component policy applies only to discovered auxiliary encoders and VAEs;
+  it cannot disable DLO for a DiT.
+- MiniMax-H3's encoder TP group is global rather than DP-replica-local. An
+  encoder TP size that spans multiple DP replicas (for example TP4 with
+  DP2/TP2 or DP2/SP2 on four ranks) is not supported for independent-prompt
+  AllGather waves: the current pipeline broadcasts rank 0's conditioning to
+  both replicas. This limitation is independent of the component policy.
 - DP concurrency requires an explicit, identical inference-step count.
 
 Sharing quantized or otherwise unvalidated transformed layouts through a