qualcomm

Development

Build, test, or develop the QNN (Qualcomm AI Engine Direct) backend. Use when working on backends/qualcomm/, building QNN (use backends/qualcomm/scripts/build.sh), adding new ops or passes, running QNN delegate tests, or exporting models for Qualcomm HTP/GPU targets. Also exposes a Buck-vs-CMake parity workflow — invoke as `/qualcomm buck-fix`, `/qualcomm buck-cmake fix`, `/qualcomm buck-parity`, or any user request to fix `test-qnn-buck-build-linux` CI failures or check buck/cmake drift in backends/qualcomm/. Also covers QNN intermediate-output / per-layer accuracy debugging — trigger on phrases like "QNN accuracy issue", "QNN output doesn't match CPU", "debug per-layer for QNN", "find which QNN layer is wrong".

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Source SKILL.md: https://github.com/pytorch/executorch/blob/HEAD/.claude/skills/qualcomm/SKILL.md

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QNN (Qualcomm AI Engine Direct) Backend

Slash command argument routing

When this skill is invoked with arguments (e.g. /qualcomm <args>), classify the args FIRST and route before doing anything else:

If args contain any of…	Route to
`buck-fix`, `buck-cmake`, `buck cmake`, `buck-parity`, `buck parity`, `buck ci`, `qnn buck`, `fix qnn ci`, `test-qnn-buck-build-linux`, or any natural-language request to fix QNN buck CI / catch buck-cmake drift	Read `buck_parity.md` and follow it end-to-end. Default mode: full iterative-fix loop. If the args also contain `check` or `diagnose`, run buck once and report only — do not apply fixes.
(no args) or any other args	Stay in this file; treat as a normal `/qualcomm` discovery request and use the Advanced Topics table below.

Advanced Topics

When the user's request falls into one of these areas, read the corresponding file before proceeding:

Topic	File	When to read
Export / lowering / quantization options / pass pipelines	`lowering_export.md`	User asks about exporting, lowering, quantization config, QuantDtype, QuantRecipe, pass pipelines
New op development	`new_op_development.md`	User asks to add/implement a new op or op builder
Model enablement	`model_enablement.md`	User asks to enable a new model end-to-end
Buck vs CMake parity (pre-PR or fix red CI)	`buck_parity.md`	User changed BUCK / TARGETS / `targets.bzl` or `CMakeLists.txt` under `backends/qualcomm/`, added new `.cpp` / `.h` / `#include` there, is preparing to push a PR that touches QNN, or the `test-qnn-buck-build-linux` CI check on their PR is red and they want to fix it locally. Direct trigger: `/qualcomm buck-fix`.
Profiling & debugging	`profiling.md`	User asks about profiling, optrace, QHAS, QAIRT Visualizer (file TBD)
QNN intermediate-output / per-layer accuracy debugging	`qnn_intermediate_debugger.md`	User reports QNN-vs-CPU accuracy divergence, asks to debug per-layer / intermediate output for QNN, mentions `QNNIntermediateDebugger` / `QcomNumericalComparator`, or wants to find which layer causes a QNN accuracy drop. Workflow generates a new debug script from the user's existing example script.

Building

Use backends/qualcomm/scripts/build.sh. Linux only (macOS not supported).

Environment variables:

QNN_SDK_ROOT — path to QNN SDK (auto-downloaded if not set)
ANDROID_NDK_ROOT — path to Android NDK (auto-downloaded if not set)

Build targets:

Target	Default	Build dir
x86_64 (Python interface + host tools)	enabled	`build-x86/`
Android arm64-v8a (device runner)	enabled	`build-android/`
Direct mode (LPAI ADSP or Hexagon CDSP)	disabled	`build-direct/`
OE Linux embedded	disabled	`build-oe-linux/`

Common build commands:

# Full build (x86_64 + Android)
./backends/qualcomm/scripts/build.sh

# x86_64 only (faster, for Python interface development)
./backends/qualcomm/scripts/build.sh --skip_linux_android

# Android only (skip x86_64)
./backends/qualcomm/scripts/build.sh --skip_x86_64

# Incremental build (skip clean)
./backends/qualcomm/scripts/build.sh --no_clean

# Enable Hexagon DSP direct mode (requires HEXAGON_SDK_ROOT, HEXAGON_TOOLS_ROOT, DSP_VERSION)
./backends/qualcomm/scripts/build.sh --enable_hexagon

# OE Linux embedded target (requires TOOLCHAIN_ROOT_HOST, TOOLCHAIN_ROOT_TARGET)
./backends/qualcomm/scripts/build.sh --enable_linux_embedded

# Release build
./backends/qualcomm/scripts/build.sh --release

# Control parallelism
./backends/qualcomm/scripts/build.sh --job_number 8

After x86_64 build, the Python interface .so files are copied to backends/qualcomm/python/ automatically.

Testing

QNN_SDK_ROOT=/path/to/qnn_sdk \
ANDROID_NDK_ROOT=/path/to/android_ndk \
LD_LIBRARY_PATH=/path/to/executorch/build-x86/lib:/path/to/qnn_sdk/lib/x86_64-linux-clang \
PYTHONPATH=$(dirname $EXECUTORCH_ROOT) \
python backends/qualcomm/tests/test_qnn_delegate.py \
    TestQNNFloatingPointOperator.test_qnn_backend_abs \
    -H $HOST -s $DEVICE_SERIAL -m SM8850 -b build-android -a /path/to/artifacts

Note (build from source): Set PYTHONPATH to the parent directory of the executorch repo root. Required because executorch.examples.qualcomm lives in the source tree and is not installed into site-packages.

Required flags: -m (SoC model), -b (Android build dir). Optional: -s (device serial), -H (host), -a (artifact dir), -c (compile only), -x (run on x86_64).

Test classes:

Class	Description
`TestQNNFloatingPointOperator`	FP16 operator tests
`TestQNNQuantizedOperator`	Quantized operator tests
`TestQNNFloatingPointModel`	FP16 model-level tests
`TestQNNQuantizedModel`	Quantized model-level tests
`TestQNNFloatingPointUtils`	FP16 utility tests
`TestQNNQuantizedUtils`	Quantized utility tests
`TestExampleLLMScript`	LLM script tests
`TestExampleMultimodalityScript`	Multimodality script tests
`TestExampleOssScript`	OSS model script tests
`TestExampleScript`	General example script tests
`TestUtilsScript`	Utility script tests