[WinUI] Perf when creating non-trivial grids (and other visual controls)

[MartyIX]

Description of Change

Notes:

• Clicking "Batch Generate Grid" multiple times lead to ever increasing time to finish the operation. I'm not sure why.

• Relevant issue [performance] all PropertyMapper's set the same values over and over #17303

• This PR is mostly a bait to attract the MAUI team's attention to the problem that it seems it's not that hard to improve status quo substantially. However, my discussion with @jonathanpeppers¹ somewhat suggests that the approach of this PR is not the best (mediocre at best I guess):

  that [this PR] would help Windows
  but same issue on all platforms, I think
  maybe this could be a redesign thing for future, like .NET 9

  me:

  maui/src/Core/src/Handlers/View/ViewHandler.Android.cs

  Line 75 in 0a562dc

  handler.ToPlatform().UpdateRotationX(view);

  - so it differs on android
  https://github.com/dotnet/maui/blob/main/src/Core/src/Handlers/View/ViewHandler.iOS.cs - all the same
  https://github.com/dotnet/maui/blob/main/src/Core/src/Handlers/View/ViewHandler.Windows.cs - all the same
  https://github.com/dotnet/maui/blob/main/src/Core/src/Handlers/View/ViewHandler.Tizen.cs - all the same
  So it seems like Android can be an exception
  and others would just handle one of these transform properties

  Jonathan:

  The part that makes me want to rethink this:

  1. Every control has TranslateX/Y default to 0
  2. Do we actually need to pass 0 to the platform? for every control?

  I think there needs to be a concept of a default value
  Where if you set TranslateX/Y it would pass to the platform and not otherwise
  But I don't know if that breaks some fundamental design
  this is just my observation
  It would also be nice to get rid of one layer of Dictionary<string, lookup if that were possible

Master

851 ms

PR:

676 ms

-> 20% faster.

Issues Fixed

Contributes to #21787

Footnotes

1. I hope he doesn't mind me copying it here. ↩

[MartyIX]

@PureWeen What do you think please?

[bcaceiro]

This looks interesting! performance should be on top of the list, and changes like this, as well as to other platforms should be really a priority. Since it is in the core, would love to see this going forward. Not developing anything for Windows, but super interested for Android and iOS

[MartyIX]

• Clicking "Batch Generate Grid" multiple times lead to ever increasing time to finish the operation. I'm not sure why.

@AdamEssenmacher Can the slowdown be caused by #21809 please?

[AdamEssenmacher]

@MartyIX I don't think so. Your Labels are getting GC'ed.

It does seem like there's a memory leak in this sample though, so the slowdown could be related to that in some way. It's just not the propagating leak I describe in #21809

I'll further observe that the major leak appearing in this sample goes away and the time to run each batch becomes very consistent if you modify the batch generation method like:

	private async void BatchGenerate_Clicked(object sender, EventArgs e)
	{
		Stopwatch sw = Stopwatch.StartNew();		

		int batchSize = int.Parse(BatchSize.Text);

		for (int i = 0; i < batchSize; i++)
		{
			contentGrid.Clear();

			for (int rowIndex = 0; rowIndex < rowCount; rowIndex++)
			{
				for (int columnIndex = 0; columnIndex < columnCount; columnIndex++)
				{
					Label label = new Label() { Text = $"[{columnIndex}x{rowIndex}]" };
					contentGrid.Add(label, column: columnIndex, row: rowIndex);
				}
			}

			await Task.Delay(500);
		}

		sw.Stop();
		info.Text = $"Grid was created {batchSize} times and it took {sw.ElapsedMilliseconds} ms in total. Avg run took {Math.Round(sw.ElapsedMilliseconds / (double)batchSize, 2)} ms";
	}

So, I suspect this batch test has something else entirely going on, most likely related to UI elements being added to the visual tree that never get a chance to be fully flushed out to the screen.

[jonathanpeppers]

Overall, this seems like it could be a temporary solution if it doesn't change any behavior.

Does this make ordering matter? What if you have code such as:

view.TranslateX = 10;
view.TranslateY = 10;
// set the other properties *after* TranslateX

For this related change for Android:

• [android] reduce JNI calls by moving logic into Java #3372

I believe it changed some behavior with handlers, so we put it in the next .NET release. So this change might be more suitable for .NET 9, so it could get more testing?

[MartyIX]

Overall, this seems like it could be a temporary solution if it doesn't change any behavior.

Mostly I was hoping that this PR would nudge the MAUI team to recognize that there is a lot of performance on the table and even with medium effort, it seems like one can make it substantially faster. I don't want really to put too much effort in this because this is not trivial for me and there is too much space for "it's nice but we decided we'll do X instead". This simply requires some coordination from the code owners. I'm not even the best to implement something like this.

For the record, I believe that your idea with default values it much much better because it would save (especially on Windows) a ton of time. But again, how can I evaluate the idea? Maybe it has been on the table before and it was rejected because who know what would it lead to.

So all in all this PR is just a demonstration that "it looks like that with a rather simple change, it can be about 20% faster". Unfortunately, for me it's still not sufficient because I need something like up to 100ms to draw a complex grid ... :-(.

Also it's not like I'm lazy. Today, for example, I spent whole day fixing a bug that spans somewhere between MAUI and WinUI and I'm on the verge of giving up ...

[jonathanpeppers]

I need something like up to 100ms to draw a complex grid

Have you thought about using SkiaSharp for this one piece of UI? You likely don't need all the rows & columns to be actual MAUI (& WinUI) Labels?

[MartyIX]

I need something like up to 100ms to draw a complex grid

Have you thought about using SkiaSharp for this one piece of UI? You likely don't need all the rows & columns to be actual MAUI (& WinUI) Labels?

I haven't mostly because it feels hard to create a data grid in 2D graphics. I don't know much about SkiaSharp. Is it somehow easy to create such data grid? I mean it sounds like a lot of low-level computing on my side to make it work.

Moreover, values in "labels" would not be easy to copy & paste, or would it?

Maybe a custom layout would be a way.

[MartyIX]

@jonathanpeppers I have come up with a different approach in #23987 (the main idea is: https://github.com/dotnet/maui/pull/23987/files#diff-fe5090f560d95c536e43dfc5f39442add6ad2d8eb555d675bdb4a0f82a30793dR35). Could you please take a look?

[jsuarezruiz]

/azp run

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