GPU Usage

Use the GPU Usage tool in the Visual Studio Performance and Diagnostics Hub to better understand the high-level hardware utilization of your Direct3D app. You can use it to determine whether the performance of your app is CPU-bound or GPU-bound and gain insight into how you can use the platform's hardware more effectively. GPU Usage supports apps that use Direct3D 12, Direct3D 11, and Direct3D 10; it doesn't support other graphics APIs such as Direct2D or OpenGL.

This is the GPU Usage Report window:

Requirements

The following are requirements for using the GPU Usage tool that are in addition to Graphics Diagnostics requirements.

• A GPU and driver that support the necessary timing instrumentation.

  Note

  For more information on supported hardware and drivers, see Hardware and driver support at the end of this document.

  For more information about Graphics Diagnostics requirements, see Getting Started.

Using the GPU Usage tool

When you run your app under the GPU Usage tool, Visual Studio creates a diagnostic session that graphs high-level information about your app’s rendering performance and GPU utilization in real-time.

To start the GPU Usage tool:

1. In the main menu, choose Debug, then Performance and Diagnostics (Keyboard: Press Alt+F2).

2. In the Performance and Diagnostics hub, check the box next to GPU Usage. Optionally, check the boxes next to other tools you’re interested in. You can run several Performance and Diagnostics tools concurrently to get a fuller picture of your app’s performance.

   

   Note

   Not all Performance and Diagnostics tools can be used at the same time.

3. Choose the blue Start button at the bottom of the Performance and Diagnostics hub to run your app under the tools you selected.

   The high-level information that’s displayed in real-time includes frame timing, frame rate, and GPU utilization. Each of these pieces of information are graphed independently, but use a common time-scale so that you can easily relate between them.

   The Frame time (ms) and Frames per second (FPS) graphs contain two red, horizontal lines that represent performance targets of 60 and 30 frames per second. In the Frame time graph, your app is exceeding the performance target when the graph is below the line and missing it when the graph is above the line. For the Frames per second graph it’s the opposite – your app is exceeding the performance target when the graph is above the line and missing it when the graph is below the line. Primarily, these graphs are used to get a high-level idea of your app’s performance and to identify slow-downs that you might want to investigate -- for example, a sudden drop in frame rate or a spike in GPU Utilization.

   While your app runs under the GPU Usage tool, the diagnostics session also collects detailed information about graphics events that were executed on the GPU. This information is used to generate a more granular report of how your app utilizes the hardware. Because this report takes some time to generate from the collected information, it’s only available after the diagnostics session is done collecting information.

   When you want to look at a performance or utilization issue more closely, stop collecting performance information so that the report can be generated.

To generate and view the GPU Usage Report:

1. In the bottom portion of the diagnostics session window, choose the Stop Collection link or press Stop in the upper left-hand corner.

   

2. In the top portion of the report, select a section from one of the graphs that shows the issue you want to investigate. Your selection can be up to 3 seconds long; longer sections are truncated towards the beginning.

   

3. In the bottom portion of the report, choose the view details link in the …click here to view details of GPU usage for that range message to view a detailed timeline of your selection.

   

   This opens a new tabbed document that contains the report. The GPU Usage report helps you to see when a graphics event is started on the CPU, when it reaches the GPU, and how long it takes the GPU to execute it. This information can help you to identify bottlenecks and opportunities for increased parallelism in your code.

Using the GPU Usage report

The top portion of the GPU Usage report displays timelines for the CPU processing activity, GPU rendering activity and GPU copy activity. These timelines are divided by light-grey, vertical bars that represent the display's vsync; the frequency of the bars matches the refresh rate of one of the displays (selected by using the Display drop-down) that GPU Usage data was collected from. Because the display might have a higher refresh rate than your app's performance target there might not be a 1-to-1 relationship between vsync and the frame-rate you want your app to achieve. To meet its performance target an app must complete all processing, perform rendering, and make a Present() call at the targeted framerate, but the rendered frame will not be displayed until the next vsync after Present().

The bottom portion displays a listing of the graphics events that occurred during the time period of the report.

Here’s the GPU Usage Report window:

Selecting one of the events in the bottom portion of the report places a marker at corresponding events in the relevant timelines, typically one event on a CPU thread that represents the API call and another event on one of the GPU timelines that represents when the GPU completed the task. Likewise, selecting one of the events in a timeline highlights the corresponding event in the bottom portion of the report.When zoomed out of the timelines in the top portion of the report, only the most time-consuming events are visible. To see events that have a shorter duration, zoom into the timelines by using Ctrl + wheel on your pointing device, or the scaling control in the lower left-hand corner of the top panel. You can also drag the timeline panel’s contents to move through the recorded events.

To help you find what you’re looking for, you can filter the GPU Usage Report based on Process names, Thread IDs, and the event name; additionally, you can choose which display's refresh rate determines the vysnc lines and you can sort events hierarchically if your app uses the ID3DUserDefinedAnnotation interface to group rendering commands.

Here are more details:

The list of events in the bottom portion of the GPU Usage Report displays the details of each event.

GPU Usage settings

You can configure the GPU Usage tool to postpone collection of profiling information, rather than starting to collect information as soon as the app starts. Because the size of the profiling information can be significant, this is useful when you know that slowdowns in your app’s performance won’t appear until later.

To postpone profiling from the start of the app:

1. In the main menu, choose Debug, then Performance and Diagnostics (Keyboard: Press Alt+F2).

2. In the Performance and Diagnostics hub, follow the settings link next to GPU Usage.

3. Under GPU Profiling Configuration, on the General property page, clear the Begin profiling at app start checkbox to postpone profiling.

   

When you postpone the collection of profiling information by using this setting, an additional link becomes available in the bottom portion of the GPU Usage tool window when you run your app under the GPU Usage tool. To start collecting profiling information, choose the Start link in the Start collecting additional detailed GPU Usage Data message.

Hardware and driver support

The following GPU hardware and drivers are supported:

Multi-GPU configurations such as NVIDIA® SLI™ and AMD Crossfire™ are not supported at this time. Hybrid graphics setup, such as NVIDIA® Optimus™ and AMD Enduro™ are supported.

See also

• Solve the Tough Graphics Problems with your Game Using DirectX Tools (video)

• GPU Usage Tool in Visual Studio (video)

• GPU Usage tool in Visual Studio 2013 Update 4 CTP1 (blog)

• GPU Usage for DirectX in Visual Studio (blog)