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feat(mm-routing): add Qwen video-aware KV routing for SGLang - #15014
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Signed-off-by: krishung5 <krish@nvidia.com>
…o-routing Signed-off-by: krishung5 <krish@nvidia.com> # Conflicts: # lib/llm/src/model_card.rs
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WalkthroughThe change adds SGLang Qwen video-routing contracts, updates Rust multimodal preprocessing, forwards validated multimodal hashes, enables frontend video decoding, and expands runtime, integration, and documentation coverage. ChangesSGLang video routing and frontend decoding
Priority: ➖ Normal Estimated code review effort: 4 (Complex) | ~60 minutes Merge Risk: 🔵 Low · up to The new video-routing test does not exercise its configured frame count, and malformed grouped hash metadata can be associated with the wrong media item. These are bounded issues but should be corrected for reliable routing validation. 🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
Full details: Docstring CoverageExplanation Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 62 functions across 16 files. (6 skipped: 6 unsupported.)
✨ Finishing Touches 💡 1🛠️ Fix failing CI checks 💡
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In `@components/src/dynamo/sglang/request_handlers/llm/mm_disagg_utils.py`:
- Around line 159-174: Update extract_mm_hashes to validate each modality’s
hash-list length against the corresponding multi_modal_data count before
flattening. Return None on any mismatch so SGLang recomputes hashes; otherwise
preserve the existing _SGLANG_MM_ITEM_MODALITY_ORDER flattening and invalid-type
handling.
In `@tests/serve/test_sglang.py`:
- Around line 713-715: Update the DYN_MM_VIDEO_NUM_FRAMES setting in the test
configuration to match the 10-frame MULTIMODAL_VIDEO_URL fixture, or replace the
fixture with one containing at least 32 frames; ensure the test’s configured
frame count matches the frames actually decoded.
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📒 Files selected for processing (22)
components/src/dynamo/sglang/register.pycomponents/src/dynamo/sglang/request_handlers/llm/decode_handler.pycomponents/src/dynamo/sglang/request_handlers/llm/mm_disagg_utils.pycomponents/src/dynamo/sglang/tests/test_sglang_frontend_decoding.pycomponents/src/dynamo/sglang/tests/test_sglang_multimodal_utils.pycomponents/src/dynamo/sglang/tests/test_sglang_video_routing.pycomponents/src/dynamo/sglang/video_routing.pycontainer/context.yamlcontainer/templates/sglang_runtime.Dockerfilecontainer/templates/wheel_builder.Dockerfiledocs/fern/pages/use-cases/multimodal-serving/additional-media-decoders.mddocs/fern/pages/use-cases/multimodal-serving/parallel-media-decoding.mddocs/fern/pages/use-cases/multimodal-serving/video-decode-gpu-requirements.mdexamples/backends/sglang/launch/agg_multimodal_router.shlib/llm/src/discovery/watcher.rslib/llm/src/local_model/runtime_config.rslib/llm/src/model_card.rslib/llm/src/preprocessor.rslib/llm/src/preprocessor/mm_routing/mod.rslib/llm/src/preprocessor/mm_routing/nemotron.rslib/llm/src/preprocessor/mm_routing/qwen3.rstests/serve/test_sglang.py
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Signed-off-by: krishung5 <krish@nvidia.com>
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Review: video-aware KV routing for SGLang Qwen
Approving. Two P3 test-coverage items, no blockers.
I checked the cache key first, because the value of this change is entirely in whether the key is right.
What goes into the key, and whether it is complete
The key has two parts, and both are covered.
The media identity is hash_video_content in lib/llm/src/preprocessor/media/rdma.rs:118. It hashes the literal video, the tensor rank, every dimension as a fixed-width integer, the dtype byte, the serialized decoded metadata, and the decoded RGB bytes. The metadata and the bytes are both length-prefixed. So the sampled frame count, the resolution, and any start or end offset all reach the key, because each of them changes either the shape or the pixel bytes. The key is the decoded content, not the URL, so a URL that changes content does not alias.
The token layout is derived from that identity plus the worker contract. Every field of the contract, including fps, max_frames and runless_boundary_hash, reaches the cohort fingerprint through qwen_video_contract_digest, and cohort_video_contract requires all members to agree. I measured this: changing sglang_preprocess.fps from 2.0 to 1.0 gives 8acba840... against the baseline 3fe5f8be..., changing max_frames gives bcaa6f4b..., and adding runless_boundary_hash gives bd127cbf.... The control, the same contract with reordered keys, gives the baseline digest unchanged.
The one per-request input that can change frame selection is mm_processor_kwargs. It fails closed at preprocessor.rs:3564 and :1317.
Whether two inputs can share a key
I could not construct a collision. The rank and each dimension are fixed-width, and the metadata and the pixel bytes are each length-prefixed, so no concatenation is ambiguous. The digest is a full 64-bit xxh3 value and is not truncated. The cohort fingerprint is a full 256-bit blake3 hex string.
The 64-bit width is the pre-existing width that images already use. It is not introduced here.
Routing, and the three fallback cases
The blast radius of a wrong key is bounded. The routing tokens pick a worker. The worker still runs its own preprocessing and its own prefix match on real token IDs, so a key that is wrong costs cache hits. It cannot serve one request the content of another.
When no worker holds the video, the router scores zero overlap and falls back to load-based selection. When the holder is gone, the standard router path applies. When the video cannot be decoded or is not eligible, preprocessor.rs:3600 clears exact_mm_routing_eligible and the request uses text-prefix routing.
A silent fallback to text-prefix routing looks healthy and answers correctly, so the test has to separate the two. This one does: tests/serve/test_sglang.py requires at least 128 cached tokens, at least 10 routing blocks, and a mean router hit rate of at least 0.9. A text-only prefix hit cannot reach 0.9 on a 10-frame video request. That is the right control.
Model coupling
The coupling is honest. _resolve_qwen_video_processor_contract publishes a contract only when model_type is one of four Qwen values and the architecture is one of four Qwen classes. A different multimodal model publishes nothing, the frontend finds no contract, and exact video routing stays off. The frame assumption is never applied to another model. The Rust side repeats the model-type check in Qwen3VideoRoutingSpec::from_model_dir.
The device coupling is honest too. enable_media_ffmpeg: "true" is now the SGLang default with no per-device override, but wheel_builder.Dockerfile:594 routes SGLang on XPU to a fixed feature list without media-ffmpeg, and the new build assertion in sglang_runtime.Dockerfile sits inside {% if device == "cuda" %}. XPU stays codec-free, as the description says.
Tests I ran, and the lane
Rust, macOS ARM64, --no-default-features --features mm-routing: 35 passed in preprocessor::mm_routing, plus tracked_video_boundary_matches_token_only_worker_contract, tracked_video_boundary_uses_native_metadata_only_when_needed, qwen_video_contract_digest_is_canonical_and_engine_specific and video_processor_runtime_contract_checksum_boundaries.
Python, AMD64, in the SGLang runtime test image with the pull-request tree overlaid: 45 passed across the three new files.
Marker selection, measured by collection in that image: video_agg_fd_qwen is selected by pre_merge and sglang and gpu_1. That is the sglang-runtime Test job in pr.yaml:861, CUDA 13.0, AMD64. Its profiled_vram_gib(18.7) is under the stage cap of 24, so it is admitted rather than deselected.
Five of eight mutants turned a test red. The three that survived are the two in the first comment and the one in the second.
Where verification stopped
I did not run a live two-worker deployment, so I did not independently reproduce the 117/118 block overlap in the description. That number is the author's.
More important, I could not verify from this repository that the frontend's replication of SGLang frame selection matches what SGLang actually derives from frontend-decoded frames. The Rust code treats the frontend's already-sampled frame count as SGLang's total_frames and reconstructs an effective frame rate from the first and last timestamps. Whether SGLang derives the same rate from the frames it receives is the load-bearing assumption of the whole path, and it is only testable against a running worker. Unverified here. The end-to-end hit-rate guard is what would catch it if it were wrong.
Related, the reconstruction of the effective frame rate from only the first and last timestamps assumes the frontend sampled uniformly. validate_input requires non-decreasing timestamps but not even spacing. I did not find a non-uniform case reachable from the shipped decoder configuration, so I am not raising it. Unverified.
|
Thank you. Primarily 2 P2 comments + ffmpeg |
Signed-off-by: krishung5 <krish@nvidia.com>
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Re-approving at 6dbaca448
My earlier approval was at 28b6eb649 and no longer covered the tree. I read the new commit in full and re-ran the work below at the live head. The approval now stands at 6dbaca448.
The push is an ordinary append. 28b6eb649 is still an ancestor of 6dbaca448, the issue timeline records no head_ref_force_pushed event, and committer dates match author dates at distinct times, so nothing was rewritten. The merge base is bbc55cb409 at both commits, so it did not move.
What changed since the approved commit, and what I re-ran
One commit, fix(mm-routing): align SGLang video routing contracts, over three files and 140 added lines. It answers four threads.
| thread | change |
|---|---|
preprocessor.rs:1169 |
early return for token-only contracts, plus tracked_mixed_token_only_boundary_preserves_canonical_pads |
qwen3.rs:289 and :298 |
float linspace frame selection with a pinned final index, plus sglang_frame_sampling_matches_numpy_float_linspace |
qwen3.rs:522 and :307 |
sglang_pre_resize_uses_ties_to_even and sglang_long_video_applies_total_pixel_budget |
video_routing.py:96 |
a ("llava", "Qwen3VLForConditionalGeneration") case |
Both of my open items are closed by mutation, each with controls that moved a different test. Details are on their own threads.
The frame-selection fix is right against real NumPy. np.linspace(0, 45, num=34, dtype=np.int64) returns exactly the 34 indices the new test lists, and the old integer-division formula first differs at index 11.
Both lanes that run the new code are named and green at this head. rust-tests builds with mm-routing at dynamo-pipeline.yml:165. pr.yaml:953 and :957 select the new Python tests pre-merge, which I measured rather than read.
I merged current main (81fa669fcb) into this head myself. It merges with no conflicts, and cargo test -p dynamo-llm --lib --no-default-features --features mm-routing -- preprocessor:: gives 283 passed and 0 failed on the merged tree, against 282 and 0 on the head alone. Five commits main gained since the merge base touch neighboring code, and none touch a file in this diff.
A divergence on this path costs a cache miss, not a wrong answer. apply_tracked_mm_replacements feeds only MmRoutingInfo, and every error path returns None and falls back to text-prefix routing. The per-request allocation is sampled_timestamps, bounded by min(contract.max_frames, input.frame_count).
One P3 stays open, on the early return at preprocessor.rs:1132. It is a guard that is no longer reachable, not a live defect, and it does not block.
I did not author any commit on this pull request.
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Previously reported defects still present:
- Original discussion: The early return at preprocessor.rs:1128 still bypasses the later normalization equality check for token-only contracts, so an inconsistent future replacement would no longer fail closed.
- Original discussion: The token-only early return remains at preprocessor.rs:1128-1132 and bypasses the normalization equality check for every block. An inconsistent token-only replacement would therefore be routed using tokens the worker does not hash instead of falling back; retain the equality check while suppressing only runless-boundary MM metadata.
- Original discussion: Verified still present: a frontend-decoded two- or three-frame clip reaches
max_frames < min_framesand disables exact routing, although SGLang's frame-count clamp can retain an even two-frame sample. The request succeeds but silently loses video-aware KV routing. - Original discussion: Verified still present: the token-only early return at
preprocessor.rs:1132bypasses the existing normalized-token equality check for every block. Current Qwen construction keeps the two forms equal, but a future contract/layout mismatch will silently route on tokens the worker does not hash instead of failing closed to text-prefix routing. - Original discussion: Verified: for 2- or 3-frame frontend-decoded clips, the added
max_frames >= min_framescheck rejects exact routing, while SGLang clamps to the available even frame count and processes the clip. Requests still succeed via text-prefix routing, but the new SGLang video-aware routing feature is silently disabled for this supported input.
Questions for the author:
- lib/llm/src/preprocessor/mm_routing/qwen3.rs: For supported vLLM and Nemotron video requests, the new no-SGLang-contract path clones
sampled_timestampsinto a Vec before immediately borrowing it. Please provide the expected frame-count distribution and an allocation or latency measurement for those existing inference paths to assess the regression.
Signed-off-by: krishung5 <krish@nvidia.com>
…o-routing Signed-off-by: krishung5 <krish@nvidia.com>
The head commit moved to f3dddc5 after this approval. The approved tree is not the tree under review now. This approval is dismissed while a new review round runs.
Signed-off-by: krishung5 <krish@nvidia.com>
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Re-review at dbf8cc83b
Approving. I found no new defect. I dismissed both of my earlier approvals first, because the head moved past the trees they covered, and I then read the whole change again rather than checking it against my old notes.
Push shape: an ordinary append, and the merge carried no edits
The chain from my last approval is 6dbaca448 to 4b6af2b24 to f3dddc585 (merge of main) to dbf8cc83b. Nothing was rewritten.
- The issue timeline records no
head_ref_force_pushedevent. repos/ai-dynamo/dynamo/compare/6dbaca448...dbf8cc83breturnsstatus: ahead,ahead_by: 41,behind_by: 0.- Locally
git merge-base --is-ancestor 6dbaca448 HEADsucceeds, on a clone wheregit rev-parse --is-shallow-repositoryprintsfalse. A shallow clone gives a wrong answer here, so I checked that first.
Of the 41 commits, only two are the author's own work. 4b6af2b24 is the code change, and dbf8cc83b removes one parametrize case from a test. The merge commit is the third. The remaining 38 arrived from main through the merge.
The merge itself is mechanical. I re-did it from 4b6af2b24 against origin/main at 9d3ce5d892 and got tree 08a0d97ae9ba3c745ffc07acffcd28e72dfd0684, which is the same tree as f3dddc585. A merge can carry hand edits, and this one does not.
Base drift: none, and the merged result is what I tested
The base branch is main. 9d3ce5d892 is both the current origin/main tip and the merge base of this PR, so there is nothing to merge in. git rev-list --count HEAD..origin/main returns 0. Because re-doing the merge reproduced the head tree exactly, every check below is already a check on the merged result, and no conflict resolution of mine can affect any finding.
The fix I can verify hardest: the short-clip clamp matches real SGLang
4b6af2b24 removes the max_frames >= min_frames guard from prepare_input and lets the clamp collapse instead. The added comment claims this matches SGLang. I read the real source in the pinned runtime image rather than trusting the comment.
sglang/srt/multimodal/processors/qwen_vl.py, SGLang 0.5.19, smart_nframes:
min_frames = ceil_by_factor(ele.get("min_frames", FPS_MIN_FRAMES), FRAME_FACTOR)
max_frames = floor_by_factor(ele.get("max_frames", min(FPS_MAX_FRAMES, total_frames)), FRAME_FACTOR)
nframes = total_frames / video_fps * fps
nframes = min(min(max(nframes, min_frames), max_frames), total_frames)
nframes = floor_by_factor(nframes, FRAME_FACTOR)There is no max_frames >= min_frames guard in SGLang, and the order is the same one the Rust now uses. The published constants also match the contract the worker sends: IMAGE_FACTOR 28, VIDEO_MIN_PIXELS 100352, VIDEO_MAX_PIXELS 602112, VIDEO_TOTAL_PIXELS 90316800, FRAME_FACTOR 2, FPS 2.0, FPS_MIN_FRAMES 4, FPS_MAX_FRAMES 768.
One detail I checked because it is easy to get wrong. SGLang floors a float, and the Rust truncates to usize first and then floors. Those agree, because floor(x/k)*k equals floor(floor(x)/k)*k for a positive integer k.
Explicit null against absent key, on the two new contract types
4b6af2b24 splits the contract into VllmQwenVideoProcessorContract and SglangQwenVideoProcessorContract. A JSON null is not the same as a missing key, so I probed both. I added one temporary test, ran it, and removed it. The mod.rs md5 before was 6a5e7ee8f51d9759fe79cf6bea79718f, the mutant differed, and the restore returned the same md5.
| case | result |
|---|---|
| vLLM key, both optional fields absent | accepted, identity MmMetadata, no SGLang preprocessing |
vLLM key, both optional fields explicitly null |
accepted, identical to the absent case |
vLLM key claiming "runless_boundary_hash": "tokens_only" |
rejected |
SGLang key, explicit null on each of the four required fields |
rejected, all four |
| SGLang key with an unknown extra field | accepted, so the shape stays forward compatible |
Explicit null and absent agree where they must, and every required field fails closed. There is no deny_unknown_fields anywhere under preprocessor/mm_routing/, so a new field added by a future worker does not break an older frontend.
Test runs, CI triage, and what I did not check
All 48 tests under preprocessor::mm_routing pass at this head with cargo test -p dynamo-llm --no-default-features --features mm-routing --lib mm_routing, on AMD64 Linux. The baseline was green before any mutation, so the mutation results above rest on a clean harness.
CI at dbf8cc83b has no failing check. Twenty jobs were still running when I finished, so I cannot read their silence as agreement. The jobs that cover this change are the SGLang CPU and GPU lanes, and I measured by collection that both pick up the new tests.
Limits of this round. I did not run the two-worker GPU end-to-end test, so the 0.9 router hit rate stays the author's measurement and the CI lane's. I did not build the SGLang CUDA image, so the new MediaDecoder build assertion is verified by reading only. I did confirm that enable_video sits behind #[cfg(feature = "media-ffmpeg")] in lib/bindings/python/rust/llm/preprocessor.rs, so that assertion is a real feature probe and not an inert one.
Open items I am not closing
The FFmpeg question on container/context.yaml:152 is still open between two maintainers, and the author has not answered it. That is a policy call about what the image is allowed to ship, not a code defect, and it is not mine to settle. I am naming it so that approving is a decision and not an oversight. On the mechanical side the image keeps its positive codec guard, which requires the VP9 encoder and rejects any H.264, H.265, AAC or NVENC encoder, and the compliance audit job is green.
One P3 from the mod.rs:55 thread is only partly closed. Making sglang_preprocess required removes the fail-open path, which was the main ask. The round-trip test still parses a hand-written JSON constant in Rust, and the Python test asserts a hand-written dict. Those two literals can still drift apart if somebody renames a field in both Python places at once. I did not measure that drift, so I am recording it as an observation rather than a finding.
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Previously reported defects still present:
- Original discussion: Still present:
video_agg_fd_qwenusesrepeat_count=3.CachedTokensChatPayloadwarms on the first request and validates cached tokens plus router hit-rate over requests after the first, sorepeat_count=2preserves the cache-hit and router-overlap coverage while avoiding the third identical expensive SGLang video inference.
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Previously reported defects still present:
- Original discussion: The SGLang video contract is still published without confirming mm_hashes support. On an older or forked engine where the handler omits mm_hashes, frontend-derived video pad values cannot match worker KV events, so exact video routing permanently misses instead of falling back to text-prefix routing.
- Original discussion: The integration payload still uses repeat_count=3. This retains a third identical, expensive video inference although the existing cache-hit and router-overlap assertions are already exercised after the warmup request.
- Original discussion: Verified still present:
register.pypublishes the SGLang exact-video contract without checkingasync_generate(mm_hashes=...)support, whileDecodeWorkerHandlersilently omits hashes when that argument is unsupported. Older or forked SGLang workers therefore receive frontend-derived routing keys but worker-derived media pads, causing permanent video-routing misses instead of the intended text-prefix fallback.
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Docs-only review.
The three changed pages are accurate for what they say, but this PR flips behavior that several unchanged docs assert the opposite of, and the headline feature — exact video-aware KV routing on SGLang — isn't documented anywhere. Inline comments cover the changed files; these are outside the diff so they can't be anchored:
1. docs/fern/pages/developer-guide/knowledge-base/modular-components/backends/sglang/multimodal.md
Four direct contradictions, three of them in one IMPORTANT block:
- Support matrix row:
**Video** | … | Aggregated: No | Disaggregated: Yes, H.264/H.265, Qwen2-family only. This PR ships aggregated Qwen3-VL video. - "The runtime image ships no software video decoder" / "Video in any other format (VP8, VP9, AV1) cannot be decoded at all" — false once
enable_media_ffmpeg: "true"lands for sglang CUDA. - "In an aggregated deployment SGLang resolves and decodes the media URL itself … video input is therefore unavailable in aggregated deployments of this image."
- "Video is also skipped for … the Qwen3-VL family … Use a Qwen2-family vision model." — Qwen3-VL aggregated video is exactly what this PR enables.
2. docs/fern/pages/use-cases/multimodal-serving/multimodal-kv-routing.md
The natural home for this feature, and it still says the opposite:
- SGLang tab: "Exact video routing is not available on this path; video requests use text-prefix routing."
- Support Matrix, SGLang row: badge
Images, note "Video requests use text-prefix routing." - "Exact Video Routing Limits" lists only the vLLM-path models. The new Qwen VL/SGLang support and its fallback conditions (legacy or mismatched worker cohorts, processor-contract mismatch) aren't there.
- "At worker startup, vLLM reports the installed processor behavior that affects this sequence" — SGLang does too now, via the contract published in
register.py. - "Verify Video Routing" is vLLM-launcher-only. The SGLang tab doesn't mention that
agg_multimodal_router.shnow passes--frontend-decoding, nor thatDYN_MM_VIDEO_NUM_FRAMEShas to match across SGLang workers.
3. backends/sglang/reference-guide.md
Still never documents --frontend-decoding, yet parallel-media-decoding.md links there for it. Pre-existing, but the flag is load-bearing for SGLang video as of this PR.
…o-routing Signed-off-by: furionw <qiwa@nvidia.com>
Signed-off-by: furionw <qiwa@nvidia.com>
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Approving again at 3e9b6672a. My last approval was at dbf8cc83b. The two commits since then are a merge of main (b2c14f3dd) and a docs update (3e9b6672a). I found no new defect.
What I tested at this head:
- The merge has one conflict, in the imports of
components/src/dynamo/sglang/register.py, and it keeps both sides. When I redo the merge, every other file matches the committed tree, so the merge carries no hand edits. - The Rust code that needs both
mm-routingandmedia-ffmpegpasses its tests at this head. It also passes at the base and at this head merged with the currentmain. No CI job has built that code at this head, so I ran it on AMD64 Linux. - The SGLang CPU lane tests pass at this head and at the base. The only difference between the two runs is the 14 tests that this PR adds.
- Mutation tests show that the tests of this PR still catch a broken fix at this head. One mutant targets the
async_generatecall that the merge changed. - The new docs match the code for the
--frontend-decodingrules and for which images build the frontend video decoder.
I did not run the two-worker GPU hit-rate test or the SGLang image build. The PR workflow last ran at dbf8cc83b, so CI has not run them at this head either.
I wrote no commits here. 4b6af2b24 contains a fix that I asked for in an earlier round.
Test counts at head, base and merge
| Run | Head 3e9b6672a |
Base 517572309 |
Head merged with main at a83ba19b4 |
|---|---|---|---|
cargo test --locked -p dynamo-llm --lib --no-default-features --features mm-routing,media-ffmpeg |
2865 passed, 0 failed | 2848 passed, 0 failed | 2865 passed, 0 failed |
pytest -m "pre_merge and sglang and gpu_0" over components/src/dynamo/sglang and tests/serve/test_sglang.py |
760 passed, 0 failed | 746 passed, 0 failed | not run |
The 17 extra Rust tests and the 14 extra Python tests at the head are the tests that this PR adds. The Python runs used the SGLang nightly image built from main at 8612fc1, with container/deps/requirements.test.txt installed and the tree first on PYTHONPATH.
Mutation results at this head, each restored to its original checksum
| Mutant | Result |
|---|---|
Put back the early return in apply_tracked_mm_replacements that 4b6af2b24 removed |
tracked_token_only_worker_still_validates_normalizable_blocks fails. The other 6 tracked_* tests pass. |
Remove **mm_hashes_kwargs from the aggregated async_generate call in decode_handler.py |
test_aggregated_forwards_grouped_mm_hashes_in_sglang_item_order fails. The other 48 tests pass. |
Control: reverse _SGLANG_MM_ITEM_MODALITY_ORDER in mm_disagg_utils.py |
That test and test_extract_mm_hashes_flattens_in_sglang_item_order fail. |
Docs claims and the evidence for each
| Docs claim | Evidence |
|---|---|
--frontend-decoding is allowed on the frontend-facing encode worker and rejected on internal EPD workers |
test_validate_accepts_frontend_decoding_with_encode_worker and both test_validate_rejects_frontend_decoding_* tests pass at this head. |
| The SGLang XPU image has no frontend FFmpeg decoder. The vLLM CPU and XPU images have it. | container/render.py for the runtime target: the SGLang XPU file builds the wheel without media-ffmpeg and copies no libav* files. The vLLM CPU, XPU and CUDA files and the SGLang CUDA file build it with media-ffmpeg. |
|
/ok to test 3e9b667 |
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/ok to test a5dcabb |
dmitry-tokarev-nv
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dmitry-tokarev-nv
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Approving again at a5dcabbbf4, tree abd99efca7. GitHub moved my approval of 3e9b6672a3 to this head after the "Update branch" merge of main. The changes of this PR are the same as in the tree that I approved, and nothing new broke.
No finding is open. CI built the SGLang image at this head, and the build step that requires the frontend video decoder passed. The rust-gpu job and the video_agg_fd_qwen test passed at 3e9b6672a3. Their runs at this head did not finish before I posted.
I wrote no commits here. 6dbaca448 and 4b6af2b24 contain tests and a fix that I asked for in earlier rounds.
What I measured at this head, with its base as the control.
| Run | Head a5dcabbbf4 |
Base 9ae086bb94 |
|---|---|---|
cargo test --locked -p dynamo-llm --lib --no-default-features --features mm-routing,media-ffmpeg |
2866 passed, 0 failed | 2849 passed, 0 failed |
pytest -m "pre_merge and sglang and gpu_0" over components/src/dynamo/sglang and tests/serve/test_sglang.py |
762 passed, 0 failed | 748 passed, 0 failed |
The extra tests at the head are the 17 Rust tests and the 14 Python tests that this PR adds. In CI, only the rust-gpu job runs the tests of the mm-routing and media-ffmpeg code. I also ran them on AMD64 Linux, with the base as the control. The Python runs used the SGLang nightly image built from main at 8612fc1. I installed container/deps/requirements.test.txt and redis 8.1.0 in it. The tree was first on PYTHONPATH.
The tests of this PR still catch a broken fix in the merged files. I restored each file to its original checksum.
| Mutant | Result |
|---|---|
Remove **mm_hashes_kwargs from the aggregated async_generate call in decode_handler.py |
test_aggregated_forwards_grouped_mm_hashes_in_sglang_item_order fails. The other 48 tests pass. |
Put back the early return in apply_tracked_mm_replacements that 4b6af2b24 removed |
tracked_token_only_worker_still_validates_normalizable_blocks fails. The other 6 tracked_* tests pass. |
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/ok to test b8d23aa |
dmitry-tokarev-nv
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dmitry-tokarev-nv
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Approving again at b8d23aa5cd. The new merge of main does not change this PR, and no finding is open.
GitHub moved my two approvals from 2026-09-23 onto this head after the merge of main, so they named code that I had not read. This approval names the code that I read.
What I found at this head:
- The merge of
mainat51b83df91fhas no conflicts and no hand edits. The 25 files of this PR add and remove the same lines as ata5dcabbbf4. mainalso changed 5 of these files. I read those changes and found no effect on the code of this PR.- The Rust tests of
dynamo-llmand the SGLang Python unit tests pass at this head and at its base. The only extra tests at the head are the 17 Rust tests and the 14 Python tests that this PR adds. - In CI at this head,
rust-gpupassed. The SGLang GPU testvideo_agg_fd_qwenalso passed. It runs two workers and requires a router KV hit rate of at least 0.9. - The open thread from harryskim on
video-decode-gpu-requirements.mdasks for a change that3e9b6672a3made. The branch rules ofmainrequire resolved threads before a merge, so that thread still blocks the merge. It is not my thread, so I did not resolve it.
I wrote no commits here. 6dbaca448 and 4b6af2b24 contain tests and a fix that I asked for in earlier rounds.
Both trees pass, and the tests of this PR catch two mutants.
| Run | Head b8d23aa5cd |
Base 51b83df91f |
|---|---|---|
cargo test --locked -p dynamo-llm --lib --no-default-features --features mm-routing,media-ffmpeg |
2877 passed, 0 failed | 2860 passed, 0 failed |
pytest -m "pre_merge and sglang and gpu_0" over components/src/dynamo/sglang and tests/serve/test_sglang.py |
765 passed, 1 skipped | 751 passed, 1 skipped |
The Rust runs used AMD64 Linux. The Python runs used the SGLang nightly image built from main at 8612fc1. I installed container/deps/requirements.test.txt and redis 8.1.0 in it, and put the tree first on PYTHONPATH. The skipped test needs CUDA.
| Mutant | Result |
|---|---|
Remove **mm_hashes_kwargs from the aggregated async_generate call in decode_handler.py |
test_aggregated_forwards_grouped_mm_hashes_in_sglang_item_order fails. The other 42 tests in its two files pass. |
In preprocessor.rs, remove the guard against two Qwen video contracts and the PadValueTokens arm of apply_tracked_mm_replacements |
dual_qwen_video_contracts_disable_exact_routing, tracked_video_boundary_matches_token_only_worker_contract and tracked_mixed_token_only_boundary_preserves_canonical_pads fail. No other test changes its result. |
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@harryskim Following up on the out-of-diff points in your docs review: they were addressed in 3e9b667.
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…o-routing Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Signed-off-by: furionw <qiwa@nvidia.com>
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/ok to test 04613ba |
7 participants
Why
SGLang RadixAttention includes multimodal identity in its prefix-cache keys, but Dynamo previously routed video requests using only their text prefix. Exact reuse requires the frontend and worker to agree on frame sampling, resizing, timestamp tokens, and placeholder expansion; otherwise the request silently misses the cached blocks. vLLM already supports VP8/VP9 frontend decoding, so its support-matrix change corrects stale documentation; this PR adds the SGLang CUDA path.
Closes DIS-2882
What Change
Test Plan
Related Issues
🚫 This PR is NOT linked to an issue:
Summary by CodeRabbit
New Features
Documentation
Tests