[Doc] fix docs Feature Design and Module Design (#283)

Signed-off-by: hsliu <liuhongsheng4@huawei.com>
Signed-off-by: Hongsheng Liu <liuhongsheng4@huawei.com>
Co-authored-by: WeiQing Chen <40507679+david6666666@users.noreply.github.com>
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Hongsheng LiuandWeiQing Chen authored and GitHub committed 2025-12-12 14:52:53 +08:00
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@@ -36,13 +36,13 @@ nav:
- design/index.md
- design/architecture_overview.md
- Feature Design:
- design/feature/multi_request_streaming_design.md
- design/feature/omni_connector_design.md
- design/feature/disaggregated_inference.md
- design/feature/multi_request_streaming.md
- design/feature/ray_based_execution.md
- Module Design:
- design/module/ar_module_design.md
- design/module/dit_module_design.md
- design/module/entrypoint_module_design.md
- design/module/ar_module.md
- design/module/dit_module.md
- design/module/entrypoint_module.md
- Docs Guide: contributing/DOCS_GUIDE.md
- API Reference:
- api/README.md
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# Summary
## Entry Points
Main entry points for vLLM-Omni inference and serving.
## Configuration
Configuration classes.
- [vllm_omni.config.model.OmniModelConfig][]
## EntryPoints
Main entrypoints for vLLM-Omni inference and serving.
- [vllm_omni.entrypoints.async_omni.AsyncOmni][]
- [vllm_omni.entrypoints.async_omni.AsyncOmniStageLLM][]
@@ -48,7 +55,6 @@ Engine classes for offline and online inference.
Core scheduling and caching components.
- [vllm_omni.core.dit_cache_manager.DiTCacheManager][]
- [vllm_omni.core.sched.omni_ar_scheduler.OmniARScheduler][]
- [vllm_omni.core.sched.omni_generation_scheduler.OmniGenerationScheduler][]
- [vllm_omni.core.sched.output.OmniNewRequestData][]
@@ -91,28 +97,14 @@ Model execution components.
- [vllm_omni.model_executor.models.qwen3_omni.qwen3_omni_moe_thinker.Qwen3_VisionPatchEmbed][]
- [vllm_omni.model_executor.models.qwen3_omni.qwen3_omni_moe_thinker.Qwen3_VisionPatchMerger][]
## Configuration
Configuration classes.
- [vllm_omni.config.model.OmniModelConfig][]
- [vllm_omni.diffusion.cache.teacache.config.TeaCacheConfig][]
## Workers
Worker classes and model runners for distributed inference.
- [vllm_omni.diffusion.worker.gpu_worker.GPUWorker][]
- [vllm_omni.diffusion.worker.gpu_worker.WorkerProc][]
- [vllm_omni.diffusion.worker.npu.npu_worker.NPUWorker][]
- [vllm_omni.diffusion.worker.npu.npu_worker.NPUWorkerProc][]
- [vllm_omni.worker.gpu_ar_model_runner.GPUARModelRunner][]
- [vllm_omni.worker.gpu_ar_worker.GPUARWorker][]
- [vllm_omni.worker.gpu_generation_model_runner.GPUGenerationModelRunner][]
- [vllm_omni.worker.gpu_generation_worker.GPUGenerationWorker][]
- [vllm_omni.worker.gpu_model_runner.OmniGPUModelRunner][]
- [vllm_omni.worker.npu.npu_ar_model_runner.NPUARModelRunner][]
- [vllm_omni.worker.npu.npu_ar_worker.NPUARWorker][]
- [vllm_omni.worker.npu.npu_generation_model_runner.NPUGenerationModelRunner][]
- [vllm_omni.worker.npu.npu_generation_worker.NPUGenerationWorker][]
- [vllm_omni.worker.npu.npu_model_runner.OmniNPUModelRunner][]
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# Profiling vLLM-Omni (update soon)
Profiling is only intended for vLLM-Omni developers and maintainers to understand the proportion of time spent in different parts of the codebase. **vLLM-Omni end-users should never turn on profiling** as it will significantly slow down the inference.
@@ -1,4 +1,4 @@
# OmniConnector: a unified connector interface of disaggregated inference for omni-modality models
# Disaggregated Inference for Omni-Modality Models
This guide explains how to configure and use distributed connectors (vllm_omni/distributed/connectors) in vllm-omni for multi-stage pipelines.
@@ -0,0 +1,47 @@
## Multi-Request Streaming (MRS) on a Single Machine
### 1. Background & Scope
- All processing runs on a single physical machine with multi-process, per-stage workers. No proxy or network transport involved.
- Current alignment with vllm-omni: `OmniLLM` supports multiple stages (`OmniStage`). GPU runners already expose streamable steps (prefill/decoding/diffusion), but the entry layer still collects lists and lacks intra-stage streaming and window scheduling.
- Goal: implement multi-stage, multi-request streaming (MRS) locally. Each stage outputs segments; downstream stages stitch and trigger compute based on configured windows. Shared memory and zero-copy strategies reduce data movement overhead.
### 2. Key Constraints
- Multi-process per stage: each stage is an independent process with a while loop; device visibility can be configured (`CUDA_VISIBLE_DEVICES`/`torch.cuda.set_device`).
- Simple IPC (copy-based): use `multiprocessing.Queue`/Pipe for inter-process communication with CPU copies/serialization; do not rely on CUDA IPC/SHM zero-copy in this version.
- Cross-stage pipeline: different stages can process different requests concurrently (e.g., stage A handles request 1 while stage B handles request 0).
### 3. Architecture Overview
- Processes & IPC queues
- Each "sub-stage" is an OS process (worker). The loop: take from input_queue → compute → put to output_queue.
- Inter-stage connection via IPC: copy-based `multiprocessing.Queue` passing dict payloads; use shared memory for large objects.
- Each link is SPSC (single-producer/single-consumer): the upstream is the orchestrator and the downstream is a single stage process; queues are unbounded (maxsize=0) on the orchestrator side.
- Device visibility
- Each stage sets `CUDA_VISIBLE_DEVICES` or calls `torch.cuda.set_device` to bind to GPU sets.
- A stage may use multiple GPUs internally (TP/PP/DP) but presents as a single stage unit.
- Simplified IPC: copy-based queues/pipes for data transfer; zero-copy is future work.
- Pipeline progression: when a stage finishes a request, it enqueues outputs to the downstream stage; if downstream is idle, it starts immediately.
- Scheduling
- A downstream stage triggers only after the upstream completes the request.
- Windowed segmentation/stitched triggering is not implemented; intra-stage streaming is not provided.
### 4. IPC Implementation (simplified: copy-based)
- Use `multiprocessing.Queue`/Pipe for inter-process communication (control + data).
- Data is serialized/copied via CPU; no CUDA IPC/SHM zero-copy in this version.
- Backpressure: queues are unbounded; pressure manifests as compute-rate differences. Optional SHM reduces large-object transfer cost; RX/decoding overhead is recorded for observability.
### 5. Scheduling & Cancellation (simplified)
- Pipeline: when a stage finishes a request, it enqueues to the next stage; that stage immediately pulls the next request from its input queue, enabling cross-stage concurrency.
- Cancellation/timeout: explicit cancellation/timeouts are not provided; graceful shutdown uses a `None` sentinel sent to each stage input queue.
#### Short sequence example (req0/req1, stage A→B)
1) t0: stage A handles req0
2) t1: req0 completes on A → enters B; A immediately starts req1
3) t2: B handles req0 while A handles req1 (parallel across stages)
### 6. Integration Points (by file)
- `vllm_omni/entrypoints/omni.py` (Orchestrator)
- Class `Omni` orchestrates multi-process stages; constructs `OmniStage` instances in parallel and spawns per-stage workers.
- Spawns stage processes per config (set `CUDA_VISIBLE_DEVICES`/`torch.cuda.set_device`), creates control/data channels, builds simple full-trigger flow.
- Stats/logging are disabled by default; per-stage and orchestrator stats are only written when explicitly enabled.
- Manages process lifecycle: start/wait for readiness, graceful shutdown; forwards results between stages using copy-based IPC and optional SHM.
- Stage readiness: each stage emits `{"type": "stage_ready"}` after initialization; the orchestrator waits for all stages or times out and logs diagnostic suggestions.
@@ -1,188 +0,0 @@
## Multi-Request Streaming (MRS) on a Single Machine
### 1. Background & Scope
- All processing runs on a single physical machine with multi-process, per-stage workers. No proxy or network transport involved.
- Current alignment with vllm-omni: `OmniLLM` supports multiple stages (`OmniStage`). GPU runners already expose streamable steps (prefill/decoding/diffusion), but the entry layer still collects lists and lacks intra-stage streaming and window scheduling.
- Goal: implement multi-stage, multi-request streaming (MRS) locally. Each stage outputs segments; downstream stages stitch and trigger compute based on configured windows. Shared memory and zero-copy strategies reduce data movement overhead.
### 2. Key Constraints
- Multi-process per stage: each stage is an independent process with a while loop; device visibility can be configured (`CUDA_VISIBLE_DEVICES`/`torch.cuda.set_device`).
- Simple IPC (copy-based): use `multiprocessing.Queue`/Pipe for inter-process communication with CPU copies/serialization; do not rely on CUDA IPC/SHM zero-copy in this version.
- Cross-stage pipeline: different stages can process different requests concurrently (e.g., stage A handles request 1 while stage B handles request 0).
### 3. Architecture Overview
- Processes & IPC queues
- Each "sub-stage" is an OS process (worker). The loop: take from input_queue → compute → put to output_queue.
- Inter-stage connection via IPC: copy-based `multiprocessing.Queue` passing dict payloads; use shared memory for large objects.
- Each link is SPSC (single-producer/single-consumer): the upstream is the orchestrator and the downstream is a single stage process; queues are unbounded (maxsize=0) on the orchestrator side.
- Device visibility
- Each stage sets `CUDA_VISIBLE_DEVICES` or calls `torch.cuda.set_device` to bind to GPU sets.
- A stage may use multiple GPUs internally (TP/PP/DP) but presents as a single stage unit.
- Simplified IPC: copy-based queues/pipes for data transfer; zero-copy is future work.
- Pipeline progression: when a stage finishes a request, it enqueues outputs to the downstream stage; if downstream is idle, it starts immediately.
- Scheduling
- A downstream stage triggers only after the upstream completes the request.
- Windowed segmentation/stitched triggering is not implemented; intra-stage streaming is not provided.
### 7. IPC Implementation (simplified: copy-based)
- Use `multiprocessing.Queue`/Pipe for inter-process communication (control + data).
- Data is serialized/copied via CPU; no CUDA IPC/SHM zero-copy in this version.
- Backpressure: queues are unbounded; pressure manifests as compute-rate differences. Optional SHM reduces large-object transfer cost; RX/decoding overhead is recorded for observability.
### 8. Scheduling & Cancellation (simplified)
- Pipeline: when a stage finishes a request, it enqueues to the next stage; that stage immediately pulls the next request from its input queue, enabling cross-stage concurrency.
- Cancellation/timeout: explicit cancellation/timeouts are not provided; graceful shutdown uses a `None` sentinel sent to each stage input queue.
#### Short sequence example (req0/req1, stage A→B)
1) t0: stage A handles req0
2) t1: req0 completes on A → enters B; A immediately starts req1
3) t2: B handles req0 while A handles req1 (parallel across stages)
### 9. Integration Points (by file)
- `vllm_omni/entrypoints/omni_llm.py` (Orchestrator)
- Class `OmniLLM` orchestrates multi-process stages; constructs `OmniStage` instances in parallel and spawns per-stage workers.
- Spawns stage processes per config (set `CUDA_VISIBLE_DEVICES`/`torch.cuda.set_device`), creates control/data channels, builds simple full-trigger flow.
- Stats/logging are disabled by default; per-stage and orchestrator stats are only written when explicitly enabled.
- Manages process lifecycle: start/wait for readiness, graceful shutdown; forwards results between stages using copy-based IPC and optional SHM.
- Stage readiness: each stage emits `{"type": "stage_ready"}` after initialization; the orchestrator waits for all stages or times out and logs diagnostic suggestions.
### 9.1 Process Device Visibility
- Device binding: set `CUDA_VISIBLE_DEVICES` before process start, or call `torch.cuda.set_device` early in init; configs can be single/multi-GPU.
- Cross-device transfer (simplified): via CPU copies; zero-copy paths are out of scope for now.
### 10. Worker Template (pseudo-code)
```python
def stage_worker(input_q, output_q, runtime, shm_threshold):
# Device binding
set_stage_gpu_devices(runtime.devices)
engine = OmniStageLLM(model, **engine_args)
batch_seq = 0
while True:
first = input_q.get()
if first is None:
break
# Batch intake (up to runtime.max_batch_size)
batch = [first]
while len(batch) < int(runtime.max_batch_size or 1) and not input_q.empty():
nxt = input_q.get()
if nxt is None:
input_q.put(None)
break
batch.append(nxt)
# Decode IPC payload and sampling params
request_ids = []
engine_inputs = []
rx_bytes = {}
rx_decode_ms = {}
for t in batch:
ein, rx = maybe_load_from_ipc_with_metrics(t, "engine_inputs", "engine_inputs_shm")
request_ids.append(t["request_id"])
engine_inputs.extend(ein if isinstance(ein, list) else [ein])
rx_bytes[t["request_id"]] = rx["rx_transfer_bytes"]
rx_decode_ms[t["request_id"]] = rx["rx_decode_time_ms"]
# Generate and dispatch (grouped by request_id)
batch_seq += 1
outputs = list(engine.generate(engine_inputs, batch[0]["sampling_params"], use_tqdm=False))
grouped = group_by_request_id(outputs, request_ids)
for rid in request_ids:
r_out = grouped.get(rid, [])
use_shm, payload = maybe_dump_to_shm(r_out, shm_threshold)
msg = {
"request_id": rid,
"metrics": {
"batch_id": batch_seq,
"rx_transfer_bytes": int(rx_bytes.get(rid, 0)),
"rx_decode_time_ms": float(rx_decode_ms.get(rid, 0.0)),
# omitted: generation latency and token stats
},
}
if use_shm:
msg["engine_outputs_shm"] = payload
else:
msg["engine_outputs"] = payload
output_q.put(msg)
```
### 12. Observability
- Metrics (as implemented):
- per-request (emitted by stages): `num_tokens_out`, `stage_gen_time_ms`, `rx_transfer_bytes`, `rx_decode_time_ms`, `rx_in_flight_time_ms`, `batch_id`
- orchestrator aggregates: E2E latency, tokens/s (written only when stats are enabled)
- optional per-stage JSONL: `{log_file}.stage{stage_id}.stats.jsonl`
- Logs/tracing:
- optional per-stage log files: `{log_file}.stage{stage_id}.log`
- the orchestrator can log readiness, forward size/time, and summary information
### 15. Risks & Mitigations
— End-to-end latency: full-trigger sacrifices interactivity; start simple/correct, add windowed streaming later.
— CPU copy overhead: copy-based IPC for maintainability; add SHM/zero-copy later as an optimization path.
### 16. Refactor: Sink LLM init and process into Stage (diagram)
Objective: without changing external call patterns, encapsulate per-stage LLM init, process creation, and worker logic inside `Stage`, so `PipelinedOmniLLM` focuses on orchestration (seeding, polling, forwarding, collecting) while keeping multi-process, shared memory, and device mapping capabilities.
Key changes (vs. current):
- Before: Orchestrator created processes directly, passing `_stage_worker`; device setup, LLM init, batching, and SHM were implemented there.
- After: enhanced `OmniStage` owns its subprocess (`init_stage_worker`), with `_stage_worker` as the entry; device setup, LLM init, batching, and SHM live in `OmniStage`.
Classes & responsibilities
- OmniLLM (orchestrator)
- Build `OmniStage` list in parallel (preserve `process_engine_inputs` wiring)
- Connect adjacent `Stage` input/output queues; seed requests to stage 0
- Poll stage outputs, decode results, call `process_engine_inputs`, then encode and forward to next stage
- Termination & cleanup: distribute shutdown signals; join/terminate subprocesses
- Stage (stage unit)
- Members: `stage_config` (with `engine_args` and `runtime`), `in_q/out_q`, subprocess handle, stats
- API:
- `init_stage_worker(...)`: spawn subprocess
- `stop_stage_worker()`: graceful exit
- `submit(ipc_payload)`: submit to input queue (may use shared memory)
- `try_collect() -> Optional[payload]`: non-blocking get from output queue
- `process_engine_inputs(stages, prompts)`: reuse/delegate existing logic
- Subprocess entry `worker_main()`:
- `set_stage_gpu_devices` (`CUDA_VISIBLE_DEVICES` & logical index mapping)
- build `OmniStageLLM(model, **engine_args)`
- while-loop:
- take first task + up to `runtime.max_batch_size-1` non-blocking; support `max_batch_size>=1`
- `maybe_load_from_ipc_with_metrics` per `engine_inputs` in batch
- `stage_engine.generate(batched_inputs, sampling_params)` (window `-1`)
- write per-request aggregated outputs to output queue after `maybe_dump_to_shm`
- log start/finish; report `error` per request on exceptions
Data flow (sketch)
```
OmniLLM
├─ Stage[0].start_process(in0, out0)
├─ Stage[1].start_process(in1, out1)
├─ ...
└─ Orchestrator loop:
- stage0.submit(encode(engine_inputs))
- for each stage:
res = stage.try_collect()
outputs = decode(res)
stage.set_engine_outputs(outputs)
if !final: next_inputs = next_stage.process_engine_inputs(stages, original_prompt)
next_stage.submit(encode(next_inputs))
```
Config (preserve & extend)
- `runtime.devices`:
- Comma-separated visibility list (e.g., "2,5,7"): set visible set; default logical index 0 (first GPU)
- Number/string: treat as logical index (0/1-based per implementation) mapping to physical GPUs
- `runtime.max_batch_size`: max requests taken per intake (default 1)
- `shm_threshold_bytes`: objects larger than this go via shared memory (default 64KB; injected into stages)
- Stage link and inputs:
- `engine_input_source`: list of upstream stage_id(s) from which the downstream stage takes inputs (typically a single source)
- `custom_process_input_func`: function to construct downstream engine_inputs from upstream outputs
- Output flags:
- `final_output`, `final_output_type`: marks that a stage produces the final external output and its type
Kept & strengthened
- Multi-process: each stage in its own process; parallel across stages; serial/batching inside a stage controlled by `max_batch_size`
- Shared memory: large objects via SHM with strict `memoryview -> close -> unlink`
- Device mapping: unified `set_stage_gpu_devices`, support comma lists and logical indices
Migration (execution order)
1) Enhanced `OmniStage` with `init_stage_worker/stop_stage_worker/submit/try_collect/_stage_worker`.
2) `OmniLLM` holds `OmniStage` instances, replacing the older pipelined class; uses Stage APIs.
3) Reuse `entrypoints/stage_utils`: device/SHM/encode-decode utilities live here.
4) Regression: single/multi-request, various `max_batch_size`, SHM threshold, device mapping, multi-stage parallelism, error paths, and shutdown flows.
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# VLLM-Omni Distributed Utilities
# Distributed utils
This directory (vllm_omni/distributed/ray_utils) contains utilities for distributed execution in vllm-omni, supporting both **Ray** and **Multiprocessing** backends.
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@@ -8,12 +8,12 @@ This section contains design documents and architecture specifications for vLLM-
## Feature Design Documents
- [Multi-Request Streaming](feature/multi_request_streaming_design.md)
- [Omni Connector Design](feature/omni_connector_design.md)
- [Disaggregated Inference](feature/disaggregated_inference.md)
- [Multi-Request Streaming](feature/multi_request_streaming.md)
- [Ray-based Execution](feature/ray_based_execution.md)
## Module Design Documents
- [AR Module Design](module/ar_module_design.md)
- [DIT Module Design](module/dit_module_design.md)
- [Entrypoint Module Design](module/entrypoint_module_design.md)
- [AR Module](module/ar_module.md)
- [DIT Module](module/dit_module.md)
- [Entrypoint Module](module/entrypoint_module.md)
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"""
DiT Cache Manager for vLLM-Omni.
This module provides caching functionality for DiT (Diffusion Transformer) models
to optimize inference performance and memory usage.
"""
class DiTCacheManager:
"""Manages DiT-specific caching for optimized inference."""
def __init__(self, config):
pass