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Local AI and new frontiers for performance evaluation

on December 19, 2023

Recently, we discussed some ways the PC market may evolve in 2024, and how new Windows on Arm PCs could present the XPRTs with many opportunities for benchmarking. In addition to a potential market shakeup from Arm-based PCs in the coming years, there’s a much broader emerging trend that could eventually revolutionize almost everything about the way we interact with our personal devices—the development of local, dedicated AI processing units for consumer-oriented tech.

AI already impacts daily life for many consumers through technologies such as such as predictive text, computer vision, adaptive workflow apps, voice recognition, smart assistants, and much more. Generative AI-based technologies are rapidly establishing a permanent, society-altering presence across a wide range of industries. Aside from some localized inference tasks that the CPU and/or GPU typically handle, the bulk of the heavy compute power that fuels those technologies has been in the cloud or in on-prem servers. Now, several major chipmakers are working to roll out their own versions of AI-optimized neural processing units (NPUs) that will enable local devices to take on a larger share of the AI load.

Examples of dedicated AI hardware in recently-released or upcoming consumer devices include Intel’s new Meteor Lake NPU, Apple’s Neural Engine for M-series SoCs, Qualcomm’s Hexagon NPU, and AMD’s XDNA 2 architecture. The potential benefits of localized, NPU-facilitated AI are straightforward. On-device AI could reduce power consumption and extend battery life by offloading those tasks from the CPUs. It could alleviate certain cloud-related privacy and security concerns. Without the delays inherent in cloud queries, localized AI could execute inference tasks that operate much closer to real time. NPU-powered devices could fine-tune applications around your habits and preferences, even while offline. You could pull and utilize relevant data from cloud-based datasets without pushing private data in return. Theoretically, your device could know a great deal about you and enhance many areas of your daily life without passing all that data to another party.

Will localized AI play out that way? Some tech companies envision a role for on-device AI that enhances the abilities of existing cloud-based subscription services without decoupling personal data. We’ll likely see a wide variety of capabilities and services on offer, with application-specific and SaaS-determined privacy options.

Regardless of the way on-device AI technology evolves in the coming years, it presents an exciting new frontier for benchmarking. All NPUs will not be created equal, and that’s something buyers will need to understand. Some vendors will optimize their hardware more for computer vision, or large language models, or AI-based graphics rendering, and so on. It won’t be enough for business and consumers to simply know that a new system has dedicated AI processing abilities. They’ll need to know if that system performs well while handling the types of AI-related tasks that they do every day.

Here at the XPRTs, we specialize in creating benchmarks that feature real-world scenarios that mirror the types of tasks that people do in their daily lives. That approach means that when people use XPRT scores to compare device performance, they’re using a metric that can help them make a buying decision that will benefit them every day. We look forward to exploring ways that we can bring XPRT benchmarking expertise to the world of on-device AI.

Do you have ideas for future localized AI workloads? Let us know!

Justin

Posted in AI, AMD, Apple, Arm, battery life, benchmark, Benchmark metrics, Benchmarking, Cloud, computer vision, Cross-platform benchmarks, Data privacy, Future of performance evaluation, graphics, Intel, large language models, Machine learning, Meteor Lake, NPU, on premises, on-device AI, PCs, Qualcomm, SaaS, WebXPRT, WebXPRT 4 | Also tagged AI, AMD, Apple, benchmark, BenchmarkXPRT, Intel, large language models, local AI, machine learning, Meteor Lake, on-device AI, Qualcomm, rendering, SaaS, WebXPRT, WebXPRT 4

Understanding the basics of AIXPRT precision settings

By Justin Greene

on September 5, 2019

A few weeks ago, we discussed one of AIXPRT’s key configuration variables, batch size. Today, we’re discussing another key variable: the level of precision. In the context of machine learning (ML) inference, the level of precision refers to the computer number format (FP32, FP16, or INT8) representing the weights (parameters) a network model uses when performing the calculations necessary for inference tasks.

Higher levels of precision for inference tasks help decrease the number of false positives and false negatives, but they can increase the amount of time, memory bandwidth, and computational power necessary to achieve accurate results. Lower levels of precision typically (but not always) enable the model to process inputs more quickly while using less memory and processing power, but they can allow a degree of inaccuracy that is unacceptable for certain real-world applications.

For example, a high level of precision may be appropriate for computer vision applications in the medical field, where the benefits of hyper-accurate object detection and classification far outweigh the benefit of saving a few milliseconds. On the other hand, a low level of precision may work well for vision-based sensors in the security industry, where alert time is critical and monitors simply need to know if an animal or a human triggered a motion-activated camera.

FP32, FP16, and INT8

In AIXPRT, we can instruct the network models to use FP32, FP16, or INT8 levels of precision:

FP32 refers to single-precision (32-bit) floating point format, a number format that can represent an enormous range of values with a high degree of mathematical precision. Most CPUs and GPUs handle 32-bit floating point operations very efficiently, and many programs that use neural networks, including AIXPRT, use FP32 precision by default.
FP16 refers to half-precision (16-bit) floating point format, a number format that uses half the number of bits as FP32 to represent a model’s parameters. FP16 is a lower level of precision than FP32, but it still provides a great enough numerical range to successfully perform many inference tasks. FP16 often requires less time than FP32, and uses less memory.
INT8 refers to the 8-bit integer data type. INT8 data is better suited for certain types of calculations than floating point data, but it has a relatively small numeric range compared to FP16 or FP32. Depending on the model, INT8 precision can significantly improve latency and throughput, but there may be a loss of accuracy. INT8 precision does not always trade accuracy for speed, however. Researchers have shown that a process called quantization (i.e., approximating continuous values with discrete counterparts) can enable some networks, such as ResNet-50, to run INT8 precision without any significant loss of accuracy.

Configuring precision in AIXPRT

The screenshot below shows part of a sample config file, the same sample file we used for our batch size discussion. The value in the “precision” row indicates the precision setting. This test configuration would run tests using INT8. To change the precision, a tester simply replaces that value with “fp32” or “fp16” and saves the changes.

Note that while decreasing the precision from FP32 to FP16 or INT8 often results in larger throughput numbers and faster inference speeds overall, this is not always the case. Many other factors can affect ML performance, including (but not limited to) the complexity of the model, the presence of specific ML optimizations for the hardware under test, and any inherent limitations of the target CPU or GPU.

As with most AI-related topics, the details of model precision are extremely complex, and it’s a hot topic in cutting edge AI research. You don’t have to be an expert, however, to understand how changing the level of precision can affect AIXPRT test results. We hope that today’s discussion helped to make the basics of precision a little clearer. If you have any questions or comments, please feel free to contact us.