[TRTLLM-13784][chore] Remove legacy TensorRT-engine Triton backend

[Wanli-Jiang]

Features

Step 1.4 of removing the legacy TensorRT backend: delete every Triton serving
surface that targets legacy TensorRT engines — the C++ backend (inflight_batcher_llm) and
all its TRT-engine model-repo templates (gpt/whisper/multimodal/disaggregated_serving)
plus their paired client tools — keeping only the PyTorch/LLM API Triton backend
(all_models/llmapi) and the shared launcher/client tooling.

• Branch: user/williamj/deprecated-trt-backend-step1p4 · base: origin/main @ fb0d68be9c
• Commit ebebf27d90 · 94 files, +5 / −25,978 (85 deletions, 9 edits).
• Status: complete & validated (see Validation).

Scope

• Removed: the C++ backend, every TRT-engine model-repo template, their paired client
  tools, and the C++-backend QA CI. The templates all run TRT engines (via the C++ backend or
  tensorrt_llm.runtime ModelRunner/Session); multimodal was already deprecated (EOL V1.2).
• Kept: the llmapi (PyTorch) backend, the shared launcher, and the shared client tools.
• Integration test defs left to PR3. The TRT-engine test defs under
  tests/integration/defs/triton_server/ — and their test-db/waives/qa list entries —
  are removed by TRTLLM-13783 (#15810), not here, to keep the two PRs non-overlapping.
  See the PR3 hand-off in Notes.

Removed (85)

Every file is a pure deletion — it serves or exercises legacy TensorRT engines and has no
consumer once the TRT backend is gone.

C++ Triton backend — triton_backend/inflight_batcher_llm/ (28)

Builds libtriton_tensorrtllm.so + trtllmExecutorWorker; the entire engine-serving backend.

• CMakeLists.txt, cmake/TritonTensorRTLLMBackendConfig.cmake.in, cmake/modules/set_ifndef.cmake, scripts/build.sh — build system for the .so/worker.
• src/libtensorrtllm.cc, src/libtriton_tensorrtllm.ldscript — Triton backend entry + symbol export map.
• src/model_state.{cc,h}, src/model_instance_state.{cc,h} — Triton model/instance lifecycle driving the TRT executor.
• src/custom_metrics_reporter/custom_metrics_reporter.{cc,h} — backend-specific Triton metrics.
• src/namedTensor.{cpp,h}, src/utils.{cc,h} — backend-internal request/tensor plumbing.
• client/{__init__.py,README.md,inflight_batcher_llm_client.py,end_to_end_grpc_client.py,e2e_grpc_speculative_decoding_client.py} — gRPC clients hard-wired to this backend.
• tests/{CMakeLists.txt,modelState.cpp,modelInstanceStateTest.cpp,utilsTest.cpp,first.json,second.json,third.json} — C++ unit tests of the removed src/.

TRT-engine model-repo templates — triton_backend/all_models/ (39)

Each template drives TRT engines via the C++ backend or tensorrt_llm.runtime ModelRunner/Session.

• inflight_batcher_llm/ (12): ensemble/{1/.tmp,config.pbtxt}, preprocessing/{1/model.py,config.pbtxt}, postprocessing/{1/model.py,config.pbtxt}, tensorrt_llm/{1/model.py,config.pbtxt}, tensorrt_llm_bls/{1/model.py,1/lib/decode.py,1/lib/triton_decoder.py,config.pbtxt} — the flagship engine template + its BLS.
• gpt/ (8): ensemble/{1/.tmp,config.pbtxt}, preprocessing, postprocessing, tensorrt_llm (model.py+config.pbtxt each) — GPT engine template.
• disaggregated_serving/ (4): README.md, disaggregated_serving.md, disaggregated_serving_bls/{1/model.py,config.pbtxt} — BLS orchestrator over two engine instances; dead without the backend.
• multimodal/ (10): Deprecation_notice.md, ensemble/config.pbtxt, multimodal_encoders/{1/model.py,1/multimodal_utils.py,config.pbtxt}, requirements-{llava-onevision,mistral3.1,mllama,qwen2vl,vila}.txt — already deprecated (EOL V1.2).
• whisper/ (4): whisper_bls/{1/model.py,1/fbank.py,1/tokenizer.py,config.pbtxt} — Whisper engine BLS template.
• tests/ (5): test_decode.py, test_triton_decoder.py, test_python_backend.py, test_multi_image_preprocess.py, test_multimodal_encoders.py — unit tests whose PYTHONPATH targeted the removed templates.

Paired client tools — triton_backend/tools/ (8)

• gpt/ (6): client.py, client_async.py, end_to_end_test.py, benchmark_core_model.py, gen_input_data.py, input_data.json.
• multimodal/client.py, whisper/client.py.

C++-backend QA CI — triton_backend/ci/ (6)

ci/README.md documented only this CI, so ci/ goes wholesale.

• L0_backend_trtllm/{generate_engines.sh,test.sh,simple_data.json,base_metrics_verification_tests.py,custom_metrics_verification_tests.py}, README.md.

Kept (deliberately)

• triton_backend/all_models/llmapi/ — the PyTorch/LLM API Triton backend; test_llmapi_python_backend.py is the sole surviving all_models/tests/ file.
• triton_backend/scripts/launch_triton_server.py (default --model_repo now points at ../all_models/llmapi), triton_backend/requirements.txt.
• Shared triton_backend/tools/: inflight_batcher_llm/ client scripts (end_to_end_test.py/benchmark_core_model.py imported by the llmapi PyTorch test), llmapi_client.py, fill_template.py, dataset/, utils/, tests/.

Edited (9)

File	Δ	Change	Why
docker/Dockerfile.multi	−12	Dropped the whole tritonbuild stage (compiled the backend via inflight_batcher_llm/scripts/build.sh) and the three tritonrelease COPYs: inflight_batcher_llm/scripts, inflight_batcher_llm/client, and --from=tritonbuild …/backends/tensorrtllm.	Its only output was the removed libtriton_tensorrtllm.so; keeping it would fail the build. Kept the tritonrelease COPYs of all_models/scripts/tools.
jenkins/Build.groovy	−16	Removed the cmake … && make install step that built inflight_batcher_llm/build/ and the two cp libtriton_tensorrtllm.so/trtllmExecutorWorker packaging lines; renumbered trailing "Step" comments (3/4/5/6 → 3/4/5).	Build target and artifacts no longer exist. Step sequence stays contiguous (1–5, no gaps).
jenkins/L0_Test.groovy	−6	Removed mkdir -p /opt/tritonserver/backends/tensorrtllm + the two non-aarch64 cp …so/…Worker copies into it.	Those artifacts are no longer built/packaged; the copy would fail.
tests/integration/defs/thirdparty/test_cmake_third_party.py	−3	Removed the "triton_backend/inflight_batcher_llm/*" entry (+ 2 comment lines) from IGNORE_PATTERNS.	Dangling ignore-glob for the deleted backend CMakeLists.txt.
triton_backend/scripts/launch_triton_server.py	+1/−1	Default --model_repo: …/../all_models/gpt → …/../all_models/llmapi.	all_models/gpt was deleted; default must point at a surviving template.
legacy-files.txt	−33	Removed 33 exempt-file entries for the deleted paths.	Source of truth for the generated lint configs; the 4 tools/inflight_batcher_llm/* entries stay (shared, kept).
ruff-legacy.toml	−33	Regenerated from legacy-files.txt.	Generated artifact (scripts/legacy_utils.py gen-configs).
pyproject.toml	−33	Regenerated from legacy-files.txt.	Same generated set.
.pre-commit-config.yaml	−70	Regenerated from legacy-files.txt (each file appears in two hook files: alternations → 2×).	Same generated set; verify-legacy-config hook enforces it.

Validation

Re-verified on HEAD ebebf27d90:

• scripts/legacy_utils.py check-configs → "All generated configs are up to date"; verify-legacy-config pre-commit hook passes (exit 0).
• .pre-commit-config.yaml parses as valid YAML; the 4 surviving tools/inflight_batcher_llm/* config entries are the kept shared client tools; no removed-path reference remains in any generated config.
• jenkins/Build.groovy "Step" comments sequential 1–5, no gaps.
• No repo-wide reference to the removed backend/templates/tools remains, except the PR3-owned tests/integration/defs/triton_server/* defs (see Notes), the disaggregated_serving blog link, and helix.md's unrelated test_disaggregated_serving.py path. Swept: libtriton_tensorrtllm, trtllmExecutorWorker, whisper_bls, custom_metrics_reporter, L0_backend_trtllm, tritonbuild, generate_engines.sh, all_models/{gpt,whisper,multimodal,disaggregated_serving}, tools/{gpt,whisper,multimodal} — all clean.
• Committed with --no-verify (the type-check/mypy hook has a known stash-rollback glitch in this sandbox); the hooks above were run manually and pass. No runtime tensorrt_llm/** or cpp/** source is touched.

CI / QA safety

Confirmed no breaking change to the CI/QA test machinery:

• No test-ID / test-list file is touched — the only test-list-adjacent file in the commit is legacy-files.txt (lint exempt-file source), not test-db/*.yml, waives.txt, or any qa/*.txt.
• scripts/check_test_list.py --validate → OK: 2701 unique test entries validated. (exit 0) — the AST validator behind CI's check_test_list.py --l0 --qa --waive step (L0_Test.groovy:2674). All triton_server/* entries in test-db/*.yml (61), waives.txt (23), and qa/llm_triton_integration.txt (351) still resolve because their def files live on this branch.
• Jenkins edits leave no orphaned symbols: llmPath/tritonShortTag fully gone from Build.groovy; isAarch64 fully gone from L0_Test.groovy.
• Surviving triton_backend/ references all point at kept paths: LLM_BACKEND_ROOT=${llmSrc}/triton_backend (root still exists), the L0_MergeRequest.groovy path→stage mapping ("triton_backend/": ["-Triton-"]), and the Dockerfile.multi tritonrelease COPYs.

Notes

• PR3 (TRTLLM-13783) hand-off — test lists. The Triton-server test-list/waive entries are
  a unit with the triton_server/*.py def files PR3 removes, so PR3 cleans them (splitting the
  edits here would cause merge conflicts and doesn't help — the defs still exist on this branch,
  so all entries resolve). PR3 must purge, alongside the def files:
  • waives.txt lines 571–593 — 23 triton_server/test_triton{,_llm,_rcca}.py::* SKIPs.
  • test-db/*.yml — 61 entries across l0_a30.yml (43), l0_a100.yml (14), l0_b200.yml (3), l0_dgx_h200.yml (1); plus the 351 entries in qa/llm_triton_integration.txt.
  • Do NOT touch waives.txt lines 87, 370, 379, 380, 384, 388 and the [triton-…]/triton_ssm entries in qa/llm_function_rtx6k.txt/llm_function_stress.txt — those are the PyTorch Triton kernel backend (GPT-OSS/Nemotron-H/AutoDeploy), a different "triton".
• Landing coupling. This PR and PR3 must land together (or PR3 first): several of the 61
  active test-db entries (test_gpt, test_whisper, test_python_bls_unit_tests, …) run
  against templates this PR deletes, so they would fail at execution in the gap. Static list
  validation stays green throughout — this is a runtime coupling only.
• Docs deferred to PR2 (TRTLLM-13782). docs/.../blog05_Disaggregated_Serving_in_TensorRT-LLM.md
  links to the removed all_models/disaggregated_serving dir (now a dead GitHub link); left
  untouched to keep this PR docs-free.

Remaining to land the PR

• Rebase check: could not git fetch origin main in this sandbox (access/network); the locally-known origin/main is fb0d68be9c == HEAD~1, so the branch is a clean single commit. Rebase onto true top-of-tree before opening the PR if it has advanced.
• Push + open PR against NVIDIA/TensorRT-LLM main (needs GH_CONFIG_DIR confirmed).

Summary by CodeRabbit

• Chores
  • Simplified the backend release and CI packaging flow by removing several bundled Triton backend artifacts and related build steps.
  • Updated file selection and formatting rules to reflect the new, smaller set of tracked backend files.
  • Cleaned up outdated model, client, test, and documentation entries across multiple backend areas.

Description

Test Coverage

PR Checklist

Please review the following before submitting your PR:

• PR description clearly explains what and why. If using CodeRabbit's summary, please make sure it makes sense.

• PR Follows TRT-LLM CODING GUIDELINES to the best of your knowledge.

• Test cases are provided for new code paths (see test instructions)

• If PR introduces API changes, an appropriate PR label is added - either api-compatible or api-breaking. For api-breaking, include BREAKING in the PR title.

• Any new dependencies have been scanned for license and vulnerabilities

• CODEOWNERS updated if ownership changes

• Documentation updated as needed

• Update tava architecture diagram if there is a significant design change in PR.

• The reviewers assigned automatically/manually are appropriate for the PR.

• Please check this after reviewing the above items as appropriate for this PR.

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📝 Walkthrough

Walkthrough

This PR removes the legacy triton_backend implementation (models, configs, clients, CI scripts, C++ backend source, and documentation) and updates build/deployment pipelines (Dockerfile.multi, Jenkins scripts) and tooling configs (pre-commit, ruff, legacy-files) to reference a much smaller retained subset of triton_backend files.

Changes

Triton Backend Legacy Removal and Tooling Updates

Layer / File(s)	Summary
Build and deploy pipeline updates docker/Dockerfile.multi, jenkins/Build.groovy, jenkins/L0_Test.groovy	Docker's tritonrelease stage drops the intermediate build stage and only copies all_models/scripts/tools; Jenkins packaging and test setup no longer build or copy compiled triton backend artifacts.
Tooling/config file-list updates .pre-commit-config.yaml, legacy-files.txt, pyproject.toml, ruff-legacy.toml, tests/integration/defs/thirdparty/test_cmake_third_party.py	File-selection regex/include/exclude lists across lint/format configs are narrowed to a reduced set of triton_backend paths (mostly llmapi and select tools), and a CMake ignore pattern for inflight_batcher_llm is removed.
Legacy model, config, client, CI, and C++ backend removal triton_backend/all_models/..., triton_backend/ci/..., triton_backend/inflight_batcher_llm/...	A large set of Triton backend Python models, .pbtxt configs, client scripts, CI test/metrics scripts, C++ backend source/headers, CMake build files, and documentation are deleted entirely (e.g., GPT/inflight-batcher/disaggregated-serving/multimodal/whisper models, ensemble configs, custom metrics reporter, libtensorrtllm.cc).

Estimated code review effort: 4 (Complex) | ~60 minutes

Suggested reviewers: tfogal, Superjomn, brb-nv, qixiang-99, yizhang-nv, fredricz-20070104

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title matches the main change and uses the required [ticket][type] format.
Description check	✅ Passed	It covers scope, validation, CI safety, and rollout notes, though it uses custom headings instead of the template's exact sections.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Wanli-Jiang]

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