Arm/resnet-18-int8-xnnpack-executorch

ResNet-18 optimized for Arm-based Edge Linux systems

An INT8-quantized version of microsoft/resnet-18 for image classification, exported to ExecuTorch (.pte) and optimized for Arm-based Edge Linux systems.

Summary

This repository contains an Arm-optimized version of microsoft/resnet-18 for image classification, quantized to INT8 via static post-training quantization — per-channel symmetric weights, per-tensor affine activations. The model is provided in ExecuTorch (.pte) format, targeting Edge Linux systems.

This version is intended to demonstrate efficient inference on Arm-based platforms while preserving the original model's intended behavior. Arm has evaluated this model on ImageNet-1k and measured performance on a representative evaluation target.

Key results

Area	Result
Model format	ExecuTorch (.pte)
Target device class	Edge Linux
Reference device	Raspberry Pi 5 (Cortex-A76, Linux Raspberry Pi OS 64-bit, based on Debian 13 "Trixie")
Primary performance result	p50 latency 8.751 ms (3.61x faster than baseline)
Accuracy result	Top-1 69.57%, Top-5 89.00%
Size / memory result	11.239 MB (3.97x smaller), peak memory 23.97 MB

Original model

Field	Value
Original model	microsoft/resnet-18
Original source	Hugging Face
Original developer	Microsoft
Original model card	microsoft/resnet-18
Original license	Apache-2.0

Model files

File	Description
resnet-18_raspberry_executorch_optimized.pte	Arm-optimized INT8 model for deployment
example.py	Minimal inference example
pyproject.toml	Pinned runtime dependencies for example.py, resolved with uv
uv.lock	Locked dependency resolution for pyproject.toml
config.yaml	Model I/O contract used by the example
benchmarks/	FP32 baseline and Arm-optimized benchmark records

Performance

Performance was measured on the reference configuration below. Results are intended to make the optimization reproducible but do not guarantee identical performance on every Arm-based system.

Reference configuration

Field	Value
Device / platform	Raspberry Pi 5
CPU	Cortex-A76, 4 cores @ 2.4 GHz
System memory	8 GB
OS	Linux, Raspberry Pi OS 64-bit, based on Debian 13 "Trixie"
Runtime	ExecuTorch 1.1.0
Execution backend	CPU (XNNPACK, KleidiAI)
Precision	INT8, static PTQ — per-channel symmetric weights, per-tensor affine activations
Batch size	1
Input resolution	224x224
Runs / warmup	100 / 10

Performance results

Metric	Original / baseline	Arm-optimized	Improvement
Model size (MB)	44.598	11.239	3.97x smaller
End-to-end latency p50 (ms)	31.563	8.751	3.61x faster
End-to-end latency p90 (ms)	31.774	8.818	3.60x faster
Model load time (ms)	98.47	39.12	2.52x faster
Time to first inference (ms)	43.477	17.108	2.54x faster
Peak memory (MB)	83.89	23.97	3.50x less
Average memory (MB)	67.08	23.97	2.80x less
Frames per second	31.68	114.28	3.61x

Accuracy

Accuracy was evaluated using the same preprocessing, input resolution, and evaluation protocol described below. Where possible, the optimized model is compared against the original model under the same evaluation conditions.

Evaluation setup

Field	Value
Dataset	ImageNet-1k
Split	val
Sample count	50000
Metric(s)	Top-1 accuracy, Top-5 accuracy
Runtime	ExecuTorch 1.1.0 (CPU, XNNPACK, KleidiAI)

Accuracy results

Metric	Original / baseline	Arm-optimized	Change
Top-1 accuracy (%)	69.76	69.57	-0.19 pp
Top-5 accuracy (%)	89.08	89.00	-0.08 pp

Accuracy was measured using the evaluation setup described above. Users should re-evaluate the model on their own data before production use.

Arm optimization approach

Arm optimized this model for efficient inference on Arm-based platforms using a hardware-aware conversion and validation flow.

For this release, Arm used:

Optimization area	Applied?	Notes
Model conversion	Yes	Converted to ExecuTorch .pte
Quantization	Yes	INT8 PTQ-static — per-channel symmetric weights, per-tensor affine activations; calibrated on 1,500 ImageNet-1k samples
Runtime/backend selection	Yes	XNNPACK + KleidiAI delegate
Graph/runtime compatibility updates	Yes	Performed as part of the ExecuTorch export pipeline
Accuracy validation	Yes	Compared against the original model or published baseline
Performance validation	Yes	Measured on the reference Arm platform

The goal of this process is to improve deployment characteristics such as latency, memory use, model size, and runtime compatibility while preserving the model's intended behavior. Detailed conversion scripts, calibration configuration, or backend-specific implementation details may be provided separately where appropriate.

Using this model

Install dependencies

Dependencies are declared in pyproject.toml, which ships with this repository. Resolve and install them into a local virtual environment with uv:

uv python install
uv sync --frozen

Run the example

uv run example.py

Expected input

Property	Value
Shape	[1, 3, 224, 224]
Dtype	float32
Range	[0.0, 1.0] before normalization; the tensor passed to the model is normalized (approximately [-2.12, 2.64])
Preprocessing	resize to 256, center crop to 224x224, to tensor, normalize (mean [0.485, 0.456, 0.406], std [0.229, 0.224, 0.225])

Expected output

Property	Value
Shape	[1, 1000]
Format	Raw class logits (unnormalized)
Postprocessing	softmax, top-5

Intended use

This model is intended for developers evaluating image classification workloads on Arm-based platforms. It is suitable as a reference implementation for benchmarking, prototyping, and integration exploration.

Limitations

• Evaluated on the full ImageNet-1k val set (50000 images)
• Fixed input size of 224x224 — the shortest edge is resized to 256 with the aspect ratio preserved, then the center 224x224 region is cropped, so content outside that crop is discarded
• Performance measurements are from Raspberry Pi 5 hardware; results may differ on other Arm devices

Additional notes

• Quantization was performed with PT2E static quantization via XNNPACKQuantizer — INT8, per-channel symmetric weights, per-tensor affine activations. No layers were kept in FP32 — all layers were quantized. Calibration used 1500 images from the ImageNet-1k val set.
• Sample input: sample_input.jpg is derived from Samoyed on Beach by Appleinfl, via Wikimedia Commons (public domain).

About this version

Original Model: microsoft/resnet-18 by Microsoft - Repository

Optimization/conversion: Arm-Optimized version for execution on Arm-based platforms.

Converted/optimized by: Arm

License: The Original Model and the Optimized Model are subject to Apache-2.0.

This repository contains a converted or optimized version of the Original Model (the “Optimized Model”). The Original Model has been converted or optimized as described above for execution on Arm-based platforms.

No retraining or fine-tuning of the Original Model was performed as part of the conversion or optimization. The conversion or optimization was not intended to change the Original Model’s behavior or intended use.

Original Model and Documentation

For information about the Original Model, including its development, training data, intended uses, limitations and other relevant information, please refer to the Original Model repository. Information in that repository was provided by the original developer or other third parties and, unless expressly stated otherwise, has not been independently verified by Arm.

Licenses and Third-Party Terms

Use of the Original Model and the Optimized Model is subject to the applicable licenses, usage restrictions and other terms identified above and in the relevant repositories. Publication of the Optimized Model does not grant any rights beyond those provided under the applicable license terms.

You are responsible for reviewing those terms and ensuring that your use of the Original Model and the Optimized Model is permitted.

Purpose of this Release

The Optimized Model is provided as a reference implementation to demonstrate and evaluate execution and performance on Arm-based systems. It is not a production-ready or supported solution.

Arm’s publication of the Optimized Model does not constitute an endorsement or certification of the Original Model or a representation that the Optimized Model is suitable for production use or any particular purpose.

To the fullest extent permitted by applicable law (i) the Optimized Model is provided “as is.” Arm makes no representations or warranties that the Original Model, the Optimized Model or their outputs are accurate, safe, secure, non-infringing, legally compliant, suitable for production use or fit for any particular purpose; and (ii) Arm will not be liable for any loss or damage arising from or in connection with the Optimized Model, its use or its outputs.

You are responsible for independently evaluating the Optimized Model, its outputs and its suitability for your intended use, including compliance with applicable legal, regulatory, safety and security requirements.

Arm does not commit to provide ongoing support, maintenance or updates for the Optimized Model. Any use of or reliance on the Optimized Model or its outputs is at your own risk.