ML Inference Advisor - Introduction

The ML Inference Advisor (MLIA) helps AI developers design and optimize neural network models for efficient inference on Arm® targets (see supported targets). MLIA provides insights on how the ML model will perform on Arm early in the model development cycle. By passing a model file and specifying an Arm hardware target, users get an overview of possible areas of improvement and actionable advice. The advice can cover operator compatibility, performance analysis and model optimization (e.g. pruning and clustering). With the ML Inference Advisor, we aim to make the Arm ML IP accessible to developers at all levels of abstraction, with differing knowledge on hardware optimization and machine learning.

Inclusive language commitment

This product conforms to Arm's inclusive language policy and, to the best of our knowledge, does not contain any non-inclusive language.

If you find something that concerns you, email terms@arm.com.

Releases

Release notes can be found in MLIA releases.

Getting support

In case you need support or want to report an issue, give us feedback or simply ask a question about MLIA, please send an email to mlia@arm.com.

Alternatively, use the AI and ML forum to get support by marking your post with the MLIA tag.

Reporting vulnerabilities

Information on reporting security issues can be found in Reporting vulnerabilities.

License

ML Inference Advisor is licensed under Apache License 2.0.

Trademarks and copyrights

Arm®, Arm® Ethos™-U, Arm® Cortex®-A, Arm® Cortex®-M, Arm® Corstone™ are registered trademarks or trademarks of Arm® Limited (or its subsidiaries) in the U.S. and/or elsewhere.
TensorFlow™ is a trademark of Google® LLC.
Keras™ is a trademark by François Chollet.
Linux® is the registered trademark of Linus Torvalds in the U.S. and elsewhere.
Python® is a registered trademark of the PSF.
Ubuntu® is a registered trademark of Canonical.
Microsoft and Windows are trademarks of the Microsoft group of companies.

General usage

Prerequisites and dependencies

It is recommended to use a virtual environment for MLIA installation, and a typical setup requires:

Ubuntu® 20.04.03 LTS (other OSs may work, the ML Inference Advisor has been tested on this one specifically)
Python® >= 3.8.1
Ethos™-U Vela dependencies (Linux® only)
For more details, please refer to the prerequisites of Vela

Installation

MLIA can be installed with pip using the following command:

pip install mlia

It is highly recommended to create a new virtual environment for the installation.

First steps

After the installation, you can check that MLIA is installed correctly by opening your terminal, activating the virtual environment and typing the following command that should print the help text:

mlia --help

The ML Inference Advisor works with sub-commands, i.e. in general a command would look like this:

mlia [sub-command] [arguments]

Where the following sub-commands are available:

"check": perform compatibility or performance checks on the model
"optimize": apply specified optimizations

Detailed help about the different sub-commands can be shown like this:

mlia [sub-command] --help

The following sections go into further detail regarding the usage of MLIA.

Sub-commands

This section gives an overview of the available sub-commands for MLIA.

check

compatibility

Lists the model's operators with information about their compatibility with the specified target.

Examples:

# List operator compatibility with Ethos-U55 with 256 MAC
mlia check ~/models/mobilenet_v1_1.0_224_quant.tflite --target-profile ethos-u55-256

# List operator compatibility with Cortex-A
mlia check ~/models/mobilenet_v1_1.0_224_quant.tflite --target-profile cortex-a

# Get help and further information
mlia check --help

performance

Estimates the model's performance on the specified target and prints out statistics.

Examples:

# Use default parameters
mlia check ~/models/mobilenet_v1_1.0_224_quant.tflite \
    --target-profile ethos-u55-256 \
    --performance

# Explicitly specify the target profile and backend(s) to use
# with --backend option
mlia check ~/models/ds_cnn_large_fully_quantized_int8.tflite \
    --target-profile ethos-u65-512 \
    --performance \
    --backend "vela" \
    --backend "corstone-300"

# Get help and further information
mlia check --help

optimize

This sub-command applies optimizations to a Keras model (.h5 or SavedModel) or a TensorFlow Lite model and shows the performance improvements compared to the original unoptimized model.

There are currently three optimization techniques available to apply:

pruning: Sets insignificant model weights to zero until the specified sparsity is reached.
clustering: Groups the weights into the specified number of clusters and then replaces the weight values with the cluster centroids.

More information about these techniques can be found online in the TensorFlow documentation, e.g. in the TensorFlow model optimization guides.

rewrite: Replaces certain subgraph/layer of the pre-trained model with candidates from the rewrite library, with or without training using a small portion of the training data, to achieve local performance gains.

Note: A Keras model (.h5 or SavedModel) is required as input to perform pruning and clustering. A TensorFlow Lite model is required as input to perform a rewrite.

Examples:

# Custom optimization parameters: pruning=0.6, clustering=16
mlia optimize ~/models/ds_cnn_l.h5 \
    --target-profile ethos-u55-256 \
    --pruning \
    --pruning-target 0.6 \
    --clustering \
    --clustering-target 16

# Get help and further information
mlia optimize --help

# An example for using rewrite
mlia optimize ~/models/ds_cnn_large_fp32.tflite \
    --target-profile ethos-u55-256 \
    --rewrite \
    --dataset input.tfrec \
    --rewrite-target fully-connected \
    --rewrite-start MobileNet/avg_pool/AvgPool \
    --rewrite-end MobileNet/fc1/BiasAdd

optimization Profiles

Training parameters for rewrites can be specified.

There are a number of predefined profiles:

Name	Batch Size	LR	Show Progress	Steps	LR Schedule	Num Procs	Num Threads	Checkpoints
optimization	32	1e-3	True	48000	"cosine"	1	0	None

##### An example for using optimization Profiles
mlia optimize ~/models/ds_cnn_large_fp32.tflite \
    --target-profile ethos-u55-256 \
    --optimization-profile optimization \
    --rewrite \
    --dataset input.tfrec \
    --rewrite-target fully-connected \
    --rewrite-start MobileNet/avg_pool/AvgPool \
    --rewrite-end MobileNet/fc1/BiasAdd_

Custom optimization Profiles

For the custom optimization profiles, the configuration file for a custom optimization profile is passed as path and needs to conform to the TOML file format. Each optimization in MLIA has a pre-defined set of parameters which need to be present in the config file. When using the built-in optimization profiles, the appropriate toml file is copied to mlia-output and can be used to understand what parameters apply for each optimization.

Example:

# for custom profiles
mlia ops --optimization-profile ~/my_custom_optimization_profile.toml

Target profiles

The targets currently supported are described in the sections below. All sub-commands require a target profile as input parameter. That target profile can be either a name of a built-in target profile or a custom file. MLIA saves the target profile that was used for a run in the output directory.

The support of the above sub-commands for different targets is provided via backends that need to be installed separately, see Backend installation section.

Ethos-U

There are a number of predefined profiles for Ethos-U with the following attributes:

+--------------------------------------------------------------------+
| Profile name  | MAC | System config               | Memory mode    |
+=====================================================================
| ethos-u55-256 | 256 | Ethos_U55_High_End_Embedded | Shared_Sram    |
+---------------------------------------------------------------------
| ethos-u55-128 | 128 | Ethos_U55_High_End_Embedded | Shared_Sram    |
+---------------------------------------------------------------------
| ethos-u65-512 | 512 | Ethos_U65_High_End          | Dedicated_Sram |
+---------------------------------------------------------------------
| ethos-u65-256 | 256 | Ethos_U65_High_End          | Dedicated_Sram |
+--------------------------------------------------------------------+

Example:

mlia check ~/model.tflite --target-profile ethos-u65-512 --performance

Ethos-U is supported by these backends:

Corstone-300
Corstone-310
Vela

Cortex-A

The profile cortex-a can be used to get the information about supported operators for Cortex-A CPUs when using the Arm NN TensorFlow Lite Delegate. Please, find more details in the section for the corresponding backend.

TOSA

The target profile tosa can be used for TOSA compatibility checks of your model. It requires the TOSA Checker backend. Please note that TOSA is currently only available for x86 architecture.

For more information, see TOSA Checker's:

Custom target profiles

For the custom target profiles, the configuration file for a custom target profile is passed as path and needs to conform to the TOML file format. Each target in MLIA has a pre-defined set of parameters which need to be present in the config file. When using the built-in target profiles, the appropriate toml file is copied to mlia-output and can be used to understand what parameters apply for each target.

Example:

# for custom profiles
mlia ops --target-profile ~/my_custom_profile.toml sample_model.tflite

Backend installation

The ML Inference Advisor is designed to use backends to provide different metrics for different target hardware. Some backends come pre-installed, but others can be added and managed using the command mlia-backend, that provides the following functionality:

install
uninstall
list

Examples:

# List backends installed and available for installation
mlia-backend list

# Install Corstone-300 backend for Ethos-U
mlia-backend install Corstone-300 --path ~/FVP_Corstone_SSE-300/

# Uninstall the Corstone-300 backend
mlia-backend uninstall Corstone-300

# Get help and further information
mlia-backend --help

Note: Some, but not all, backends can be automatically downloaded, if no path is provided.

Available backends

This section lists available backends. As not all backends work on any platform the following table shows some compatibility information:

+----------------------------------------------------------------------------+
| Backend       | Linux                  | Windows        | Python           |
+=============================================================================
| Arm NN        |                        |                |                  |
| TensorFlow    | x86_64 and AArch64     | Windows 10     | Python>=3.8      |
| Lite Delegate |                        |                |                  |
+-----------------------------------------------------------------------------
| Corstone-300  | x86_64 and  AArch64    | Not compatible | Python>=3.8      |
+-----------------------------------------------------------------------------
| Corstone-310  | x86_64 and  AArch64    | Not compatible | Python>=3.8      |
+-----------------------------------------------------------------------------
| TOSA checker  | x86_64 (manylinux2014) | Not compatible | 3.7<=Python<=3.9 |
+-----------------------------------------------------------------------------
| Vela          | x86_64 and  AArch64    | Windows 10     | Python~=3.7      |
+----------------------------------------------------------------------------+

Arm NN TensorFlow Lite Delegate

This backend provides general information about the compatibility of operators with the Arm NN TensorFlow Lite Delegate for Cortex-A. It comes pre-installed.

For version 23.05 the classic delegate is used.

For more information see:

Arm NN TensorFlow Lite Delegate documentation

Corstone-300

Corstone-300 is a backend that provides performance metrics for systems based on Cortex-M55 and Ethos-U. It is only available on the Linux platform.

Examples:

# Download and install Corstone-300 automatically
mlia-backend install Corstone-300
# Point to a local version of Corstone-300 installed using its installation script
mlia-backend install Corstone-300 --path YOUR_LOCAL_PATH_TO_CORSTONE_300

For further information about Corstone-300 please refer to: https://developer.arm.com/Processors/Corstone-300

Corstone-310

Corstone-310 is a backend that provides performance metrics for systems based on Cortex-M85 and Ethos-U.

For access to AVH for Corstone-310 please refer to: https://developer.arm.com/Processors/Corstone-310
Please use the examples of MLIA using Corstone-310 here to get started: https://github.com/ARM-software/open-iot-sdk

TOSA Checker

The TOSA Checker backend provides operator compatibility checks against the TOSA specification. Please note that TOSA is currently only available for x86 architecture.

Please, install it into the same environment as MLIA using this command:

mlia-backend install tosa-checker

Additional resources:

Source code: https://review.mlplatform.org/admin/repos/tosa/tosa_checker
PyPi package https://pypi.org/project/tosa-checker/

Vela

The Vela backend provides performance metrics for Ethos-U based systems. It comes pre-installed.

Additional resources:

https://pypi.org/project/ethos-u-vela/