Essential WPF

In this great WPF performance session, Bart De Smet and Eric Harding have talked about WPF performance and demonstrates some of the performance tools the WPF team uses.

One of the important things to do regards performance is to start measure early. Perceived performance, make it feel fast, turn it to an art and not a science. There would be trade offs – CPU versus memory, etc.

Memory

New WPF application called FishBowl has been announced. It’s a small application dealing with facebook as a case study.

To profile memory do:

• Run the application
• Open process explorer (the app wastes 150mb)
• Open VMMap to break down memory usage and shows where memory is going Both in native and managed heap.
  • Render uses native memory
  • Images uses native memory
• Open .NET Memory Profile – WPF team uses it – see where memory was allocated
• Look at the shortest root path to know who holds the objects

Cold Start

To profile cold start do:

• Prevent unnecessary DLLs from being loaded
• Set xperf to run at startup – this shows how much CPU by process also disk IO
• Use .NET memory profiler again to know what object was loaded

Warm Start

To profile warm start do:

• Run the application
• Use WPF Perf Visual Profiler, and attach to application to analyze the visual tree (how many elements loaded)
• Use CPU profile such in Visual Studio Profiler to look for the hot path with higher CPU time

Runtime

To profile runtime do:

• Use WPF Perf Visual Profiler to see were CPU spend its time
• Use perforator to see rendering performance
  • High IRTs (GPU) may effect frame rate – effects, clips, opacity and opacity mask
  • Element count may increase IRTs – input and routed events
• In .NET 4.0 here is a Cache Composition trading video memory with CPU

Runtime Best Practice

• Don’t block UI thread
• Use UI Virtualization and Data Virtualization when possible
• Freeze your freezables – no change notification callbacks
• Hardware vs Software
  • RDP, virtual machines, old hardware
  • RenderCapability.Tier
  • Reduce frame rate, 3D rendering

This is it for this session. In a future post I’ll describe this process in more details.