Windows 11 24H2 Update: Enhancing App Performance with User-Mode Work Submission

As Windows 11 prepares for its latest update, known as 24H2, users can look forward to more than just enhancements related to artificial intelligence. The update, expected to roll out in September or October 2024 on Intel and AMD PCs, introduces an intriguing new feature designed to improve the performance of many applications. This feature, termed "User-mode work submission," will allow apps to communicate more swiftly with the GPU, enhancing both speed and efficiency.

Unpacking the User-mode Work Submission Feature​

The new User-mode work submission feature is particularly significant for applications that rely on frequent small tasks being sent to the GPU. Traditionally, applications, especially those requiring intensive graphics processing, such as video editors or gaming software, experience delays caused by the time it takes to queue tasks to the GPU. With this new API, apps can communicate directly with the GPU, reducing latency and improving response times.

How It Works​

With this feature, applications no longer need to go through multiple layers to submit their requests to the GPU. Instead, they can directly submit workloads, optimizing performance for tasks that require quick, repetitive submissions. As Microsoft officially states in its support documentation, “The goal is to improve performance of applications that submit small workloads frequently to the GPU.” Furthermore, the implementation of GPU "doorbells" assists this process. Doorbells are notifications that alert the GPU when new tasks are available. Microsoft has delineated two distinct models of doorbells:

• Global Doorbells: All queues share a single notification system that the GPU checks continuously.
• Dedicated Doorbells: Each task queue maintains its own notification mechanism, simplifying task management for the GPU. By utilizing these models, Windows aims to streamline the communication process further and ensure that tasks are dispatched with minimal waiting time.

Implications for Performance​

The User-mode work submission feature is poised to have a substantial impact on applications running inside containers or virtual machines. This enhancement is particularly relevant as more users migrate to virtualized environments for their computing needs. As stated in Microsoft's documentation, applications running in VMs can significantly benefit from reduced overhead when submitting tasks, achieving much lower latency and potentially better overall application performance.

Energy Management Considerations​

A key concern with increased reliance on GPU tasks is the potential for increased power consumption. Microsoft has addressed this by ensuring that User-mode work submission integrates seamlessly with Windows’ existing engine state transition mechanisms. This system helps manage the power state of the GPU, switching it between high-power modes for busy tasks and low-power modes when idle. This ensures that while performance is increased, energy efficiency is not compromised. When an application sends a request for the GPU, this triggers a transition into a high-performance state, which reverts once tasks are complete and no further requests are pending.

Historical Context and Evolution​

Windows 11 24H2’s approach to GPU communication and performance optimization reflects a continuing trend within operations systems to enhance efficiency. Over the years, Microsoft has made several strides towards increasing application performance through enhanced graphics processing. The introduction of DirectX and advancements in graphics driver interfaces has laid the groundwork for more sophisticated interactions between applications and GPUs. The Windows Display Driver Model (WDDM), which continually evolves, illustrates Microsoft's commitment to incorporating advanced technologies that optimize the user experience. In past updates, elements such as hardware acceleration and optimizations for specific application types were included; however, the degree of interaction introduced with User-mode work submission is a more granular improvement that promises to refine operational efficiencies even further.

User Experience and Expected Benefits​

With an eye on the growing demand for faster, more responsive application performance, Windows 11 24H2’s new API can shape how users experience daily tasks. Users running graphic-intensive applications can expect noticeable improvements in performance, whether through faster rendering times, smoother playback in video editing tools, or improvements in gaming visuals. The broader implications also extend to developers who will need to consider these new capabilities when designing software for Windows environments. Enhanced performance features may require updates to existing applications to maximize the benefits provided with the 24H2 update. Furthermore, as the Windows user base adopts GPU-centric workloads more aggressively in cloud-based and high-performance computing scenarios, this enhancement becomes even more critical. It arms users with the tools needed to efficiently leverage GPU resources without significant trade-offs in operational efficiency.

Conclusion​

Windows 11 24H2 is set to deliver impressive enhancements that extend beyond its AI-oriented improvements. The introduction of User-mode work submission reveals Microsoft's dedication to refining how applications interact with hardware, particularly GPUs. As we anticipate the wider rollout later this year, users can be excited about the prospect of faster, more efficient applications—a crucial factor in today's resource-intensive computing landscape. For further reading and detailed information, refer to the original article on Windows Latest: Windows 11 24H2's new feature could help some apps run faster.