how to profile silverlight mvvm application with a lot of custom controls

Question

There is a quite big LOB silverlight application and we wrote a lot of custom controls which are rather heavy in drawing.

All data is loaded by RIA service, processed and bound (using INofityPropertyChanged interface) to the view.

The problem is that first drawing takes a lot time. Following calls to the service (server) and redrawing is quite fast.

I used Equatec profiler to track the problem. I saw that processing takes a couple of miliseconds only so my idea is that the drawing by SL engine is slow.

I'm wondering if it is possible to profile somehow processes inside SL to check which drawing operations are taking too much time. Are there any guidelines how to implement faster drawing of complex custom controls?

Answer 1

Short answer is - No, there's no super easy way of figuring out why your application is slow.

Long Answer:
I have never used Equatec profiler for Silverlight but it seems similar to dotTrace. Either way, they both end up showing the same information as xPerf.
Basically the information you should have in front of you is saying which methods and classes took up the most time to execute.

If that information points back to Silverlight framework graphics engine (agcore.dll and npctrl.dll), you'll have to start a slow process of figuring out what you did wrong.
At this point I strongly recommend that you'll watch every single talk Seema Ramchandani gave about Silverlight performance. Specifically PDC08, Mix09 and Mix10.

Step #1 of perf optimization: Measure. Measure. Measure.
Have a clear baseline of what you're trying to improve, and set a numeric expectation to when performance is good enough.
That way you can verify that your changes are having a positive impact on performance.

Step #2 of perf optimization: Start removing stuff.
In your case, I'd start commenting out controls out off the form. When perf massively improves, you've found your culprit.

Step #3 of perf optimization: Try to fix the weak link.

That's how I would go about solving this issue.

Sincerely,
-- Justin Angel

Answer 2

Try profiling with the Visual Studio profiler in order to get a good measure of your managed code and the native code executing within Silverlight. The profiler will help point you to where you're spending the most of your time (what the hot path's are) and whether or not your spending it in framework (SL) code or your own code.

The basics of profiling are:

1. Open a Visual Studio Command Prompt (as admin), 'cd' to the directory where your DLL and PDB files are (typically your "Debug" folder)
2. VSPerfClrEnv /sampleon
3. VSPerfCmd -start:sample -output:somefile.vsp VSPerfCmd -globalon VSPerfCmd -launch:"c:\Program Files (x86)\Internet Explorer\iexplore.exe" -args:""
4. VSPerfCmd -shutdown
5. VSPerfClrEnv /off

You can find detailed instructions on using the profiler on my blog: http://www.nachmore.com/2010/profiling-silverlight-4-with-visual-studio-2010/

If you find that you are spending time within Silverlight, track down the code path to see where your code is triggering the expensive calls, so that you can then investigate specific solutions based on the cause of the slow down.

Hope that helps,

• Oren