--- title: Analyzing Apple GPU performance using the shader cost graph framework: xcode role: article role_heading: Article path: xcode/analyzing-apple-gpu-performance-using-shader-cost-graph-a17-m3 --- # Analyzing Apple GPU performance using the shader cost graph Discover potential shader performance issues by examining pipeline states. ## Overview Overview One key method of triaging performance bottlenecks is to look at the most expensive shaders to understand which functions and lines are the most costly. The shader cost graph allows you to quickly find and triage expensive pipeline states and shaders. important: The shader cost graph feature is available for iOS devices with A17 Pro or later, and Mac computers with M3 or later. View the shader cost graph To open the shader cost graph, click the Performance button in the Metal debugger’s Debug navigator, and then click the Shaders tab above the Performance timeline. note: The shader cost graph is available for pipeline states only. When you select a pipeline state in the Timeline navigator, the shader cost graph for that pipeline state’s shaders appears on the right. Switch between shader types By default, selecting a render pipeline state shows the fragment shader cost graph. Selecting a compute pipeline state shows the compute shader cost graph. You can switch between different shader types using the Vertex and Fragment tabs above the shader cost graph. Navigate the shader cost graph The shader cost graph in the top section left-aligns the most expensive shader function calls, and shows the function call stack from top to bottom. The shader source code of the corresponding shader type appears below the graph. You can select a function in the shader cost graph to view its shader source code below in the source editor. Understand per-line costs The percentage weights appear in the gutter of the shader source code to the left of the lines of code. The pie chart to the right of each weight contains performance statistics to help you improve the shader code. Hover over a pie chart to display the detailed breakdown of the instructions of a line. The instruction details include the following runtime statistics infomation: | | | | | | The shader source line may consist of multiple instructions with different instruction types. For example, sampling a texture may involve math, sample, and synchronization instructions. The instruction details include the following possible instruction types and their cost: Math Comparison Select Bit Manipulation Conversion Permute Reduce Control Flow Predication Sample Synchronization Load Store Load Store Atomic Barrier Fragment Feedback Vertex Processing Image Access Data Movement Ray Tracing Image Block Load Image Block Write Image Write Each arithmetic instruction may operate on different data types, such as half-floats or integers. The instruction details include the following possible data types and their cost: Float16 Float32 Integer Bits Switch between per-line metric modes In the shader source code control bar, you can choose different modes for the per-line shader profiling statistics in the gutter. Options include the following: | | | | For more information about the Metal profiling tools for M3 and A17 Pro, see Discover new Metal profiling tools for M3 and A17 Pro. ## See Also ### Metal workload analysis - [Analyzing your Metal workload](xcode/analyzing-your-metal-workload.md) - [Analyzing resource dependencies](xcode/analyzing-resource-dependencies.md) - [Analyzing memory usage](xcode/analyzing-memory-usage.md) - [Analyzing Apple GPU performance using a visual timeline](xcode/analyzing-apple-gpu-performance-using-a-visual-timeline.md) - [Analyzing Apple GPU performance using counter statistics](xcode/analyzing-apple-gpu-performance-using-counter-statistics.md) - [Analyzing Apple GPU performance with performance heat maps](xcode/analyzing-apple-gpu-performance-using-performance-heatmaps-a17-m3.md) - [Analyzing non-Apple GPU performance using counter statistics](xcode/analyzing-non-apple-gpu-performance-using-counter-statistics.md)