How To Scale ML Inference to Improve Reliability, Speed, and Cost Efficiency

Last updated: 2023-03-23

While you can argue on the legitimate use of the acronym AI, you cannot ignore that today, machine learning models play a vital role in various industries, from healthcare and finance to autonomous vehicles and marketing. Moreover, as machine learning models become more complex, the demand for reliable, fast, and cost-efficient inference solutions has grown. In this blog post, I’ll explore the strategies and technologies you need to scale machine learning inference for optimal performance and cost-effectiveness. I will cover popular technologies such as Nvidia Triton Inference Server, TorchServe, ONNX, Torch Dynamo, Facebook AITemplate, and OpenAI Triton, highlighting their unique features and benefits and discussing the need for proper GPU workload scheduling and orchestration.

Understanding Machine Learning Inference

What is Inference?

After a machine learning model has been trained on a dataset and learned the underlying patterns, it can be used to generate predictions new inoputs or unseen data. This process called inference is crucial for deploying machine learning models in real-world applications, as it allows organizations to harness the power of their models and derive actionable insights from data.

Machine learning inference is generally performed on different profiles of hardware than during the training phase. Training is generally computationally intensive and requires powerful GPUs or clusters. On the other hand, inference can be executed on various devices, from cloud-based servers to edge devices.

Challenges in Scaling Inference

As machine learning models become increasingly complex and the demand for real-time predictions grows, organizations face several challenges when it comes to scaling inference:

• Latency: Ensuring low-latency predictions is essential, particularly for applications requiring near real-time decision-making, such as fraud detection systems or applications with stringent UX expectations. As the number of requests for inference increases, providing timely results becomes increasingly critical.
• Throughput: Scaling inference involves handling many parallel requests efficiently. Maximizing throughput, or the number of predictions made per unit of time, is crucial for meeting the demands of high-traffic applications and maintaining a responsive system.
• Cost Efficiency: Running inferences on powerful hardware can be expensive, and organizations must balance performance and cost. Optimizing the utilization of available resources and minimizing the cost per prediction is essential for long-term viability.
• Reliability: Ensuring consistent performance and high availability is essential for business-critical applications that rely on machine learning models. Maintaining system stability and minimizing downtime become top priorities as inference workloads scale.

Addressing these challenges requires the implementation of advanced technologies and strategies designed to optimize machine learning inference. In the following sections, we’ll explore popular solutions like NVIDIA Triton Inference Server, TorchServe, Torch Dynamo, Facebook AITemplate, and OpenAI Triton, which have been developed to help organizations overcome these obstacles and achieve scalable, reliable, and cost-efficient inference.

Serving Models for Inference

NVIDIA Triton Inference Server

Overview and Features

NVIDIA Triton Inference Server (formerly known as TensorRT Inference Server) is an open-source platform designed to optimize and scale machine learning inference across a wide range of deep learning frameworks and models. Triton offers a comprehensive solution for deploying AI models in production, addressing the challenges associated with latency, throughput, cost efficiency, and reliability.

Notable features of the NVIDIA Triton Inference Server include:

• Multi-framework support: Triton is compatible with various deep learning frameworks, such as TensorFlow, PyTorch, ONNX Runtime, and TensorRT. This flexibility allows organizations to use their preferred frameworks and models without being locked into a specific ecosystem.
• Model ensemble support: Triton enables the creation of model ensembles, which combine multiple models into a single pipeline for more accurate and efficient predictions.
• Dynamic batching: Triton supports dynamic batching to optimize resource utilization and throughput, automatically aggregating multiple inference requests for more efficient execution.
• Model versioning: Triton simplifies model deployment and management with built-in support for model versioning, allowing organizations to roll out updates and improvements seamlessly.
• GPU support: Triton is designed to leverage the power of NVIDIA GPUs, enabling accelerated inference and improved performance.

Implementing Triton for Scalable Inference

To deploy machine learning models using NVIDIA Triton Inference Server, follow these steps:

1. Install Triton: First, you need to install Triton on your target hardware. You can use the pre-built Docker container provided by NVIDIA or build Triton from the source code. For detailed installation instructions, refer to the official documentation.
2. Prepare your models: Convert your trained machine-learning models into a format supported by Triton. This step may involve exporting models from TensorFlow, PyTorch, or other frameworks to ONNX or TensorRT formats. Additionally, organize your models in a directory structure that follows Triton’s model repository layout.
3. Configure Triton: Create a configuration file for each model you want to deploy, specifying parameters like input and output tensor names, dimensions, data types, and optimization settings. For more information on creating configuration files, consult the Triton documentation.
4. Launch Triton: Start the Triton server with your prepared model repository, specifying the path to your models and any additional settings like the number of GPUs, HTTP/GRPC ports, and logging preferences.
5. Send inference requests: Once Triton runs, you can send inference requests to the server using HTTP or gRPC APIs. In addition, client libraries are available for various programming languages, making integrating Triton with your existing applications easy.

By implementing NVIDIA Triton Inference Server, you can unlock the potential of your machine learning models with scalable, efficient, and reliable inference, addressing the challenges associated with deploying AI solutions in production environments.

TorchServe

Introduction to TorchServe

TorchServe is an open-source, flexible, easy-to-use tool for serving PyTorch models in production environments. Developed jointly by AWS and Facebook, TorchServe aims to streamline the process of deploying, managing, and scaling machine learning models built with PyTorch. In addition, it provides a performant, lightweight solution for organizations looking to overcome the challenges of inference scaling, such as latency, throughput, and cost efficiency.

The main features of TorchServe include the following:

• Native PyTorch support: TorchServe is specifically designed to work seamlessly with PyTorch models, eliminating the need for model conversion or additional tooling.
• Model versioning: TorchServe supports model versioning, allowing for simplified model management and seamless updates.
• Batching: TorchServe offers configurable batching support to optimize resource utilization and improve throughput.
• Customizable pre and post-processing: TorchServe allows you to easily integrate custom pre-processing and post-processing steps into your inference pipeline, enabling greater control over the entire process.
• Metrics and monitoring: TorchServe exposes various metrics via a RESTful API, making it simple to monitor the performance and health of your deployed models.

Deploying Models with TorchServe

To deploy your PyTorch models using TorchServe, at a high level, you will have to follow these steps:

1. Install TorchServe: Begin by installing TorchServe and its dependencies. You can do this using pip or by building TorchServe from the source. For detailed installation instructions, refer to the official documentation.
2. Export your model: Export your trained PyTorch model as a TorchScript file using the torch.jit.trace or torch.jit.script methods. TorchScript is a statically-typed subset of Python that can be optimized and executed by the Torch JIT (Just-In-Time) compiler, improving inference performance.
3. Create a model archive: Package your TorchScript model and any necessary metadata and configuration files into a model archive file. This file is a compressed archive containing all the required components for TorchServe to serve your model.
4. Start TorchServe: Launch TorchServe with your model archive, specifying the desired settings for REST APIs, logging, and other configurable options.
5. Send inference requests: Once TorchServe runs, you can send inference requests to the server using the REST APIs. In addition, client libraries are available for various programming languages, making integrating TorchServe with your existing applications easy.

By deploying your PyTorch models with TorchServe, you can take advantage of a streamlined, performant, and easy-to-use serving solution explicitly designed for PyTorch, enabling you to address the challenges of scaling machine learning inference in production environments.

ONNX Inference: A Unified Approach to Machine Learning Inference

Introduction to ONNX

The Open Neural Network Exchange ( ONNX) is an open standard for representing machine learning models developed by an open source community with open governance. Founding members include Microsoft, Facebook, and IBM. ONNX provides a standard format for model interchange between deep learning frameworks, such as TensorFlow, PyTorch, and Caffe2. By using ONNX, developers can more easily move models between frameworks, simplifying the process of deploying and scaling machine learning inference.

ONNX Runtime is a cross-platform, high-performance inference engine for ONNX models. With ONNX Runtime, you can run machine learning models on various hardware and platforms, including CPUs, GPUs, and edge devices, ensuring efficient resource utilization and optimized performance.

Benefits of ONNX Inference

Some of the main benefits of ONNX inference include the following:

• Framework interoperability: ONNX allows you to move models between different deep learning frameworks, providing flexibility and reducing vendor lock-in.
• Optimized performance: ONNX Runtime employs various optimization techniques to ensure low latency and high throughput during inference, addressing the challenges associated with scaling machine learning inference.
• Hardware compatibility: ONNX Runtime supports various hardware configurations, including CPUs, GPUs, and edge devices, enabling you to deploy models across diverse environments. 10.3 Deploying ONNX Models for Inference

To leverage ONNX for scalable machine learning inference, at a high level, you will follow these steps:

1. Convert your model to ONNX format: Export your trained machine learning model from your preferred deep learning framework (e.g., TensorFlow or PyTorch) to the ONNX format using the appropriate conversion tools or libraries. Refer to the ONNX tutorials.
2. Install ONNX Runtime: Install the ONNX Runtime inference engine on your target platform, ensuring you have the necessary dependencies and hardware support.
3. Load and run your ONNX model: Use the ONNX Runtime APIs to load your ONNX model, prepare input data, and execute inference requests. The APIs are available for various programming languages like Python, C++, and C#.
4. Integrate with serving solutions: You can also deploy your ONNX models using popular serving solutions, such as NVIDIA Triton Inference Server or TorchServe, which offer native support for ONNX models.

By adopting ONNX and ONNX Runtime for your machine learning inference pipeline, you can benefit from a unified, cross-platform approach that enables efficient resource utilization, optimized performance, and seamless deployment across various deep learning frameworks and hardware configurations.

Model Optimization for Inference

Torch Dynamo

The Role of Torch Dynamo in Inference Scaling

Torch Dynamo is a Just-In-Time (JIT) compiler developed by Facebook to optimize and accelerate the execution of PyTorch models. Torch Dynamo significantly reduces latency and improves inference performance by converting PyTorch models into efficient, low-level code. This process allows organizations to scale their machine learning inference workloads more effectively, addressing the challenges of latency, throughput, and cost efficiency.

Torch Dynamo achieves performance improvements by applying a series of optimizations, such as:

• Operator fusion: Combining multiple operations into a single one, reducing the overhead of executing them individually.
• Kernel specialization: Generating specialized versions of kernels for specific input shapes and data types, resulting in more efficient execution.
• Memory optimizations: Reducing memory usage by reusing memory buffers and minimizing intermediate allocations.

Integrating Torch Dynamo with Your Machine Learning Pipeline

To leverage Torch Dynamo for optimizing your PyTorch models at a high level, you will have to follow these steps:

1. Install Torch Dynamo: Ensure you have the latest version of PyTorch installed, as Torch Dynamo is integrated into Torch as a JIT compiler since version 1.13. For older torch versions, you may need to use the legacy torchdynamo repositiory.
2. Convert your model to TorchScript: Export your trained PyTorch model as a TorchScript file using the torch.jit.trace or torch.jit.script methods. This process allows Torch Dynamo to apply its optimizations to the model during the JIT compilation process.
3. Deploy your optimized model: With Torch Dynamo enabled, you can deploy your optimized TorchScript model using your preferred serving solution, such as TorchServe or NVIDIA Triton Inference Server.

By integrating Torch Dynamo into your machine learning pipeline, you can significantly improve the performance of your PyTorch models during inference, enabling you to address the challenges of scaling machine learning inference workloads and achieving better resource utilization, lower latency, and higher throughput.

Facebook AITemplate (AIT)

A Glimpse into Facebook AITemplate

Facebook AITemplate is an open-source, customizable, high-performance framework that renders neural networks into high-performance CUDA/HIP C++ code. Developed by Facebook, AITemplate is designed to provide high-performance, open, and flexible deep learning model inference, focusing on compatibility and extendability for both NVIDIA and AMD GPU platforms.

The key benefits of Facebook AITemplate (AIT) include:

• High performance: AIT achieves close to the maximum potential performance (roofline) on NVIDIA GPU TensorCore and AMD GPU MatrixCore for fp16 (half-precision floating-point) calculations. It supports major models such as ResNet, MaskRCNN, BERT, VisionTransformer, and Stable Diffusion, implying that it is efficient and optimized for various AI tasks.
• Unified, open, and flexible: AIT offers a unified framework for deep neural network models that work seamlessly with NVIDIA and AMD GPUs, allowing developers to leverage their capabilities without worrying about GPU-specific implementations. In addition, being fully open-source, AIT encourages collaboration and adaptability, making it easier for developers to extend and improve the framework.
• Extensive fusion support: AIT supports a more comprehensive range of fusions than existing solutions for both NVIDIA and AMD GPU platforms, which can lead to better performance and resource utilization.

Leveraging AITemplate for Enhanced Inference

To deploy your machine learning models using Facebook AITemplate, at a high level, you will follow these steps:

1. Install AITemplate: Begin by installing AITemplate and its dependencies. Refer to the official documentation for detailed installation instructions.
2. Prepare your models: Export your trained machine learning models and define AIT modules by following the tutorial How to inference a PyTorch model with AIT
3. Deploy your AIT model to your inference server: Deploy your template to a solution like NIVIDIA Triton Inference Server or TorchServe. Once your AITemplate model is deployed, you can send inference requests to your inference server and benefit from AITemplate optimization.

By deploying your machine learning models with Facebook AITemplate, you can use a highly optimized, unified, and open-source framework that offers seamless integration with NVIDIA and AMD GPUs. This process enables rapid inference serving, better resource utilization, and improved performance across a wide range of deep learning models, ultimately enhancing your AI-driven applications and solutions.

OpenAI Triton

Exploring OpenAI Triton

OpenAI Triton (not to be confused with NVIDIA Triton Inference Server) is an open-source programming language and compiler specifically designed for high-performance numerical computing on GPUs. Developed by OpenAI, Triton aims to simplify the process of writing high-performance GPU code (custom GPU kernels), allowing developers and researchers to more easily leverage the power of GPUs for machine learning and other computationally intensive tasks.

Triton provides a Python-embedded domain-specific language (DSL) that enables developers to write code that runs directly on the GPU, maximizing its performance. The Triton compiler takes care of the low-level optimizations and code generation, allowing developers to focus on the high-level logic of their algorithms.

Some key benefits of OpenAI Triton include the following:

• Improved performance: Triton can deliver performance close to hand-tuned CUDA code, enabling researchers and developers to perform better without spending extensive time on low-level optimizations.
• Ease of use: Triton is designed to be easier than traditional GPU programming languages like CUDA, allowing developers to implement and optimize their algorithms for GPU execution more quickly.
• Integration with Python: Triton’s Python-embedded DSL enables developers to write and execute GPU code directly from Python scripts, simplifying the development process and making it more accessible to researchers and engineers familiar with the Python programming language.

Overall, OpenAI Triton aims to make GPU programming more accessible and efficient, allowing researchers and developers to more easily tap into the power of GPUs for high-performance computing tasks.

Integrating OpenAI Triton into Your Inference Pipeline

To leverage OpenAI Triton to accelerate your machine learning models at a high level, you will follow these steps:

1. Install OpenAI Triton: Begin by installing the Triton compiler and its dependencies. Detailed installation instructions can be found in the official documentation
2. Implement custom GPU kernels: Write custom GPU kernels using OpenAI Triton’s Python-like syntax, focusing on the specific operations and optimizations most relevant to your machine learning workloads.
3. Compile and test your kernels: Compile your custom Triton kernels and test them for correctness and performance. Benchmark your kernels against existing implementations to ensure your optimizations are effective.
4. Integrate Triton kernels into your models: Modify your machine learning models to use your custom Triton kernels instead of the default implementations provided by your deep learning framework. This process may involve updating your model code or creating custom PyTorch or TensorFlow layers that utilize your Triton kernels.
5. Deploy your optimized models: With your custom Triton kernels integrated, deploy your optimized machine learning models using your preferred serving solution, such as NVIDIA Triton Inference Server or TorchServe.

By incorporating OpenAI Triton into your machine learning pipeline, you can unlock significant performance improvements, enabling you to overcome the challenges of scaling machine learning inference and achieving better resource utilization, lower latency, and higher throughput.

Specialized GPU Orchestration and Scheduler for Optimizing GPU Usage

The Importance of GPU Orchestration and Scheduling

As organizations scale their machine learning inference workloads, effective management and utilization of GPU resources become crucial for achieving cost efficiency, high throughput, and low latency. Specialized GPU orchestration and scheduling solutions can help optimize GPU usage by allocating resources intelligently, monitoring workloads, and ensuring optimal performance across multiple models and devices.

These solutions play a critical role in handling various challenges associated with GPU usage, such as:

• Resource contention: Ensuring fair allocation of GPU resources among multiple models and users, preventing bottlenecks and performance degradation.
• Dynamic scaling: Automatically scaling GPU resources in response to changing workload demands, maximizing resource utilization and cost efficiency.
• Fault tolerance: Monitoring GPU health and managing failures gracefully, ensuring continuous operation and minimizing downtime.

Key Solutions for GPU Orchestration and Scheduling

Some of the famous GPU orchestration and scheduling solutions include:

1. Kubernetes: Kubernetes is a widely used container orchestration platform that can be extended with tools like Kubeflow and NVIDIA GPU Operator to manage GPU resources effectively. Kubernetes can schedule and manage GPU-accelerated machine learning workloads, ensuring efficient resource utilization and seamless scaling.
2. Apache Mesos: Though close to being relegated to the Attic, Apache Mesos is a distributed systems kernel that provides fine-grained resource management for GPU-accelerated workloads. With frameworks like Marathon and NVIDIA DC/OS GPU, Mesos can efficiently orchestrate GPU resources and manage machine learning inference tasks. Unless you already depend on Mesos, I would not do a new deployment on this technology.
3. SLURM: SLURM is an open-source workload manager designed for Linux clusters, including GPU-accelerated systems. SLURM provides advanced scheduling capabilities for GPU resources, allowing users to allocate GPUs based on various constraints, such as memory, power usage, and device type.

Many commercial options are available for AI Orchestration that often work on top of a Kubernetes deployment like run.ai.

Embracing a Comprehensive Approach to Inference Scaling

In this blog post, I explored several cutting-edge technologies designed to address the challenges of scaling machine learning inference, including NVIDIA Triton Inference Server, TorchServe, Torch Dynamo, Facebook AITemplate, and OpenAI Triton. Each solution offers unique features and capabilities that cater to different requirements and preferences.

Addressing the challenges of scaling machine learning inference for reliability, speed, and cost efficiency requires a comprehensive approach considering various aspects, including serving technologies, GPU management strategies, and model interchangeability. In this blog post, I have explored different cutting-edge solutions designed to tackle these challenges, such as NVIDIA Triton Inference Server, TorchServe, ONNX inference, Torch Dynamo, Facebook AITemplate, OpenAI Triton, and specialized GPU orchestration and scheduling solutions. Of course, there is a lot more that I could have covered, including the considerable improvements coming with PyTorch 2.0 or open-source framework like Kernl that help optimize and accelerate PyTorch models.

To achieve optimal performance and resource utilization, balancing the chosen inference technologies and GPU management strategies is crucial. Consider factors such as framework compatibility, hardware requirements, customizability, ease of integration, and the unique requirements of your machine learning workloads when selecting the best-suited technologies for your use case.

You can effectively scale your machine learning inference workloads by thoroughly evaluating your options and integrating the right mix of serving platforms, GPU orchestration solutions, and model interchange standards like ONNX. This comprehensive approach will enable your organization to address the challenges associated with scaling model inference, ensuring optimal performance, reliability, and cost efficiency.