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rfdetr-seg: Triton kernel for pre-processing (Jetson Orin NX 8GB) [Includes changes from #2403]#2404

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rfdetr-seg: Triton kernel for pre-processing (Jetson Orin NX 8GB) [Includes changes from #2403]#2404
aseembits93 wants to merge 29 commits into
roboflow:mainfrom
aseembits93:opt-preprocess+opt-python-postproc

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@aseembits93 aseembits93 commented Jun 3, 2026

What does this PR do?

It adds the optimized RF-DETR Triton preprocessing path on top of the Triton RLE postprocess branch. End-to-end numbers for this PR therefore represent the cumulative postproc + preproc gain.

The preprocessing fast path is guarded by:

INFERENCE_MODELS_RFDETR_TRITON_PREPROC_ENABLED=true

The implementation uses a two-pass Triton resize/normalize flow:

  • pass 1: PIL-compatible antialias horizontal resize into a uint8 CHW scratch buffer
  • pass 2: vertical resize + /255 + normalization into the TensorRT input tensor

The low-level kernels live in triton_preprocess.py. The TensorRT adapter delegates fast-path eligibility, reusable buffer state, warning throttling, and CUDA event handoff to FastPreprocessRuntime in triton_preprocess_runtime.py. That runtime caches resample tables, pinned host input, device input, scratch buffers, and a ring of output tensors so later pipelined execution can reuse buffers safely. The fast path remains opt-in and falls back to the reference path with a RuntimeWarning when the request is outside the supported Triton contract.

Type of Change

  • Other: Performance improvement

Testing

  • I have tested this change locally
  • I have added/updated tests and benchmark coverage for this change

Test details: (Make sure Triton is installed in your environment)

  • Cumulative postproc + preproc gains on TensorRT video input

Reference command on main:

INFERENCE_MODELS_RFDETR_TRITON_POSTPROC_ENABLED=false \
  INFERENCE_MODELS_RFDETR_TRITON_PREPROC_ENABLED=false \
  ENABLE_AUTO_CUDA_GRAPHS_FOR_TRT_BACKEND=false \
  RFDETR_PIPELINE_DEPTH=1 \
  PYTHONPATH=<repo>:<repo>/inference_models \
  python development/stream_interface/rfdetr_nano_seg_trt_workflow.py \
    --video_reference <video> \
    --backend trt

Candidate command on opt-preprocess:

INFERENCE_MODELS_RFDETR_TRITON_POSTPROC_ENABLED=true \
  INFERENCE_MODELS_RFDETR_TRITON_PREPROC_ENABLED=true \
  ENABLE_AUTO_CUDA_GRAPHS_FOR_TRT_BACKEND=false \
  RFDETR_PIPELINE_DEPTH=1 \
  PYTHONPATH=<repo>:<repo>/inference_models \
  python development/stream_interface/rfdetr_nano_seg_trt_workflow.py \
    --video_reference <video> \
    --backend trt

vehicles_312px.mp4 (538 frames, src 312x176):

fps elapsed ms/frame
main reference 34.58 15.56 s 28.92
Triton postproc + preproc 50.00 10.76 s 20.00
Delta +44.6% -4.80 s -8.92 ms

vehicles_720p.mp4 (538 frames, src 1280x720):

fps elapsed ms/frame
main reference 18.25 29.48 s 54.79
Triton postproc + preproc 29.97 17.95 s 33.37
Delta +64.2% -11.53 s -21.42 ms

vehicles_1080p.mp4 (538 frames, src 1920x1080):

fps elapsed ms/frame
main reference 10.76 49.98 s 92.94
Triton postproc + preproc 18.99 28.33 s 52.66
Delta +76.5% -21.65 s -40.28 ms
  • Correctness on 1000 same-shape COCO val2017 images vs main flags-off
PARITY_MODEL_PATH=<repo>/rfdetr-seg-nano-orin-trt-package \
  PYTHONPATH=<repo>:<repo>/inference_models \
  python development/stream_interface/rfdetr_coco_same_shape_parity.py \
    --base-ref main \
    --candidate-ref opt-preprocess \
    --coco-dir <repo>/coco/val2017 \
    --height 480 \
    --width 640 \
    --image-count 1000 \
    --warmup-frames 10
main flags-off opt-preprocess
Images 1000 1000
Detections 5959 5959
Matched same-class IoU > 0.5 5959 (100.00%)
Count-mismatch images 0
Class-id disagreements 0
Mean / min box IoU 0.999992 / 0.981132
Mean / max |Δscore| 0.000e+00 / 0.000e+00
Mean / min mask IoU 0.999497 / 0.000000
Byte-identical RLEs 5954 / 5959
  • Preprocess microbench replay from captured e2e inputs

Triton replay exercises the production FastPreprocessRuntime helper used by the TRT adapter; the harness only materializes captured inputs and compares outputs.

PYTHONPATH=<repo>:<repo>/inference_models \
  python development/stream_interface/rfdetr_preprocess_microbenchmark.py \
    --mode replay \
    --cases-dir <captured-cases-dir> \
    --replay-implementation <reference|triton> \
    --repeats 3 \
    --warmup-repeats 1 \
    --device captured \
    --atol 1e-6

Each row uses 100 captured calls and 300 timed replays per implementation. These numbers were rerun after replay was switched to the production FastPreprocessRuntime helper.

captured case set reference mean / p50 / p90 / p99 Triton mean / p50 / p90 / p99 mean speedup
vehicles_312px 3.204 / 3.128 / 3.518 / 4.089 ms 0.745 / 0.707 / 0.916 / 0.971 ms 4.30x
vehicles_720p 14.957 / 14.837 / 15.084 / 17.787 ms 1.151 / 1.104 / 1.421 / 1.495 ms 12.99x
vehicles_1080p 30.697 / 29.415 / 34.063 / 35.713 ms 1.884 / 1.837 / 2.098 / 2.180 ms 16.29x

All Triton replay outputs matched captured reference outputs at atol=1e-6.

  • Unit tests and compile checks
python -m py_compile \
  development/stream_interface/rfdetr_coco_same_shape_parity.py \
  development/stream_interface/rfdetr_preprocess_microbenchmark.py \
  inference_models/inference_models/configuration.py \
  inference_models/inference_models/models/rfdetr/rfdetr_instance_segmentation_trt.py \
  inference_models/inference_models/models/rfdetr/triton_preprocess.py \
  inference_models/inference_models/models/rfdetr/triton_preprocess_runtime.py \
  inference_models/tests/integration_tests/models/test_rfdetr_seg_predictions_trt.py \
  inference_models/tests/unit_tests/models/rfdetr/test_triton_preprocess.py \
  inference_models/tests/unit_tests/models/rfdetr/test_trt_preprocess_fast_path.py

PYTHONPATH=<repo>:<repo>/inference_models \
  python -m pytest -q \
    inference_models/tests/unit_tests/models/rfdetr/test_pre_processing.py \
    inference_models/tests/unit_tests/models/rfdetr/test_triton_preprocess.py \
    inference_models/tests/unit_tests/models/rfdetr/test_trt_preprocess_fast_path.py

RFDETR_SEG_TRT_PACKAGE_PATH=<repo>/rfdetr-seg-nano-orin-trt-package \
  PYTHONPATH=<repo>:<repo>/inference_models \
  python -m pytest -q \
    inference_models/tests/integration_tests/models/test_rfdetr_seg_predictions_trt.py::test_trt_triton_preprocess_output_matches_reference_preprocess

Results: unit coverage 40 passed; model-level Triton preproc parity 1 passed
with the local Orin TRT package override. The default T4 fixture skips cleanly
on this Orin runtime due TensorRT serialized-engine platform mismatch.

Checklist

  • My code follows the style guidelines of this project
  • I have performed a self-review of my own code
  • My changes generate no new runtime errors in the tested paths above
  • I have updated the documentation accordingly (if applicable): changelog updated

Additional Context

Replace the per-frame PIL-bilinear-antialias + to_tensor + normalize chain
in the RF-DETR TRT instance-segmentation model with a single Triton
kernel that resizes, swaps BGR↔RGB, scales by 1/255, and applies
ImageNet normalization — writing straight into the preallocated TRT
input buffer.

Byte-exact port of PIL's separable bilinear-antialias resize
(PRECISION_BITS=22, int32 fixed-point, uint8 quantization between the
horizontal and vertical passes). The horizontal uint8 intermediate
lives in registers.

Correctness
- Preproc max abs error vs PIL: 4.77e-7 (fp32 ULP on the final
  /255+normalize step; the uint8 resize result is byte-identical).
- Full coco/val2017 detection parity (rfdetr-seg-nano, conf=0.4):
  26,721 / 26,721 matched at IoU>0.5, mean box IoU 1.0000,
  |Δscore| 0, 0 class-id disagreements, all matched masks
  pixel-identical.

Performance (vehicles_312px.mp4, 538 frames)
- Baseline (PIL path): 76.25 fps
- Triton fast path:    99.83 fps (+31%)
- Preproc microbench (1080p → 312²): 27.0 ms → 2.8 ms per frame (~10×)

Scope
- Gated on: single-image numpy uint8 HWC input, stretch/letterbox/
  center-crop/letterbox-reflect resize modes (all collapse to a single
  PIL stretch when dataset_version_resize_dimensions is None, verified
  via synthetic-package test), no static_crop/grayscale/contrast,
  3-channel, scaling_factor in {None, 255}, normalization set.
- Falls back to the existing PIL-based pre_process_network_input
  when any precondition fails.

Also adds the benchmark driver
development/stream_interface/rfdetr_nano_seg_trt_workflow.py used to
measure the above numbers.
INFERENCE_MODELS_RFDETR_TRITON_PREPROC_ENABLED (default true). Setting
it to false short-circuits _try_fast_preprocess so every call falls
back to the PIL reference path — useful for A/B benchmarking and as an
escape hatch if the fused kernel is ever implicated in a regression.

e2e on vehicles_312px.mp4 (538 frames, rfdetr-seg-nano TRT, mean of 3):
  ON  (default): 98.57 fps
  OFF (env=false): 76.60 fps
  Δ: +28.7% / −2.90 ms/frame
@aseembits93 aseembits93 changed the title rfdetr-seg: Triton kernel for post-processing (Jetson Orin NX 8GB) [Includes changes from #2403] rfdetr-seg: Triton kernel for pre-processing (Jetson Orin NX 8GB) [Includes changes from #2403] Jun 3, 2026
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