qualcomm

name

qualcomm

description

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".

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