[Android] CollectionVIew scrolling performance on MAUI lags compared to XF

[PureWeen]

Description

Given the following layout

<ContentPage>
     <CollectionView x:Name="cvGrid" Background="Yellow" HorizontalOptions="Fill"
                             BackgroundColor="Black">
		<CollectionView.ItemTemplate>
			<DataTemplate>
				<Grid BackgroundColor="Purple" ColumnDefinitions="25,25,25,25,25,25,25,25,25,25,25">
					<Label Grid.Column="0" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="1" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="2" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="3" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="4" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="5" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="6" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="7" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="8" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="9" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="10" TextColor="White" Text="{Binding Symbol}"></Label>
					<Label Grid.Column="11" TextColor="White" Text="{Binding Symbol}"></Label>
				</Grid>
			</DataTemplate>
		</CollectionView.ItemTemplate>
	</CollectionView>
</ContentPage>

the performance on XF is much better than MAUI

Steps to Reproduce

Run the following projects on Android and you'll notice that the scrolling on XF is super smooth compared to MAUI. If you perform really fast scrolling, XF remains smooth whereas MAUI starts to glitch and slow down.

MAUI:
MauiCollectionView.zip

XF:
XFCOllectionView.zip

I didn't test this on WinUI/iOS yet but it would be good to validate there as well

Link to public reproduction project repository

No response

Version with bug

8.0.0-rc.2.9373

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android

Did you find any workaround?

No response

Relevant log output

No response

Related Issues

#20433
#19933
#20797

[Amir000001]

this problem also exists in net 7

[PureWeen]

Related #17326

[mattleibow]

Just tested iOS, wow, much slow.

[mjsb212]

I'm having a similar problem with GridItemsLayout and described what I've tried/found in: #17326 -- Does anyone know if the issues are related??

[Alex-Dobrynin]

@PureWeen I have noticed that CreateContent() of datatemplate is much slower than in XF, may be here is the problem. because the same template in XF takes 30 ms to create and 200 ms in MAUI.
I supposed that MAUI should be much performant than XF but it is not

[mikebikerider]

I observed CollectionView sluggishness in MAUI .NET 7, and even more with .NET 8 iOS compared to Xamarin forms. Multiple issues with grids not resizing properly. Star columns and rows do not behave as expected. I moved a big Xamarin iOS project to MAUI .NET 7, I will not publish it. Will keep updating Xamarin.Forms version. With Android it is even worse. Resizing issues worse than with iOS, CollectionView scrolling slower and jerkier. My Android Xamarin.Forms apps run faster than iOS counterparts. MAU Android apps significantly slower than MAUI iOS. Waiting for .NET 8 was a big disappointment. It brought further performance degradation instead of improvement. I like MAUI coding, but MAUI GUI performance is not acceptable.

[BaY1251]

any plan for it?

[Redth]

It's worth noting that if anyone is looking at the speed of scrolling in CollectionView or ListView while debugging their app through Visual Studio, it is definitely going to be slower than on an actual release build. The reason for this is there's a lot more visual tree interaction happening with the live visual tree tooling which slows things down significantly.

Having said that, it does seem like it might be slower than it could be on Android even in a release build. I'm working on collecting some traces so we can look at the details a bit more and see where time is being spent.

[Redth]

Here's a speedscope trace from this app running on a Pixel 4 in release mode...
dotnet-dsrouter.exe_20231205_163422.speedscope.json

Here's a video of the app running:
https://github.com/dotnet/maui/assets/271950/f97cfdf8-631b-4a26-8386-1cc4f40c33bf

I think this is running reasonably fast looking at the video, and nothing stands out too much from the speedscope trace.

@jonathanpeppers thoughts?

[Alex-Dobrynin]

@Redth as i said before, CreateContent() method of DataTemplate is much slower in MAUI than in XF on same templates both in debug mode. in XF it takes 20 -30ms to construct template, in MAUI takes 200 ms. Maybe this is the case

[jonathanpeppers]

The CreateContent() method is showing a small % in the .speedscope file above:

When looking for low-hanging fruit while scrolling, I tended to look for things in the 2% range. But there still could be something done here that would help.

I added this section, as this seems to be coming up a lot:

• https://aka.ms/profile-maui#feature-xyz-was-faster-in-xamarinforms

[jonathanpeppers]

One thing I do see, I think we could completely eliminate this call:

Where it only calls into C# from Java if the TextView.Text is a "formatted string". So plain strings could avoid the interop.

[mikebikerider]

@Redth, is it worth comparing scrolling in CollectionView or ListView in release mode to scrolling of CollectoinView or ListView in Xamarin.Forms in any mode?
I moved a 5 years old Xamarin.Forms project to MAUI .NET 7. Xamarin.Forms ListView and CollectionView scrolling on a physical device (Samsung Galaxy S20) is smooth and fast even when run in Visual Studio debugger with Hot Reload enabled. The MAUI app scrolling is slower, and it is jerky when running on the same device in release mode directly. Pretty much same on iOS, only Android is worse. I think there is more than one cause for poor performance. MAUI Grid.

From Microsoft online documentation https://learn.microsoft.com/en-us/dotnet/maui/user-interface/layouts/grid?view=net-maui-8.0

Caution
Try to ensure that as few rows and columns as possible are set to Auto size. Each auto-sized row or column will cause the layout engine to perform additional layout calculations. Instead, use fixed size rows and columns if possible. Alternatively, set rows and columns to occupy a proportional amount of space with the GridUnitType.Star enumeration value.

Somehow in Xamarin.Forms using 'auto' rows and columns did not cause problems I could notice, and Xamarin.Forms Star rows and columns resize as documented. Not in MAUI .NET 7 or .NET8. Star columns and rows behave like 'auto' and that affects controls they are hosting, and controls that are hosting grid cells. ListView and CollectionView in my apps use one-row multiple columns Grid in the DataTemplate. One of the columns is always Star. Other columns width is bound to datasource (List<>). In Xamarin.Forms it works like a charm. In MAUI works too but does not resize properly when device is rotated.
The app has 7 pages that have either ListView or CollectionView. In theXamarin.Forms app none of the pages has OnSizeAllocated(). I can rotate the device and everything including CollectionView/ListView resizes correctly. In MAUI the same XAML and code behind produce wrong sizing on load and when device is rotated and not just for CollectionView. In MAUI I had to write OnSizeAllocated() for each page to make it look more or less right, like I did in early Xamarin days. I tried .NET 8 when it was released in November. It is so much worse I went back to .NET 7.
The added MAUI code is different between iOS and Android projects. Xamarin.Forms beats MAUI in the 'write code once' area too.
If I would not have the Xamarin.Forms app in respective app stores since 2018 and vastly outperforming the MAUI version I might even publish the iOS version. Android still requires some work. But it makes no sense.

[jonathanpeppers]

is it worth comparing scrolling in CollectionView or ListView in release mode to scrolling of CollectoinView or ListView in Xamarin.Forms in any mode?

That's why we added the section at the top here: https://aka.ms/profile-maui#feature-xyz-was-faster-in-xamarinforms

Compare Release vs Release.

[mikebikerider]

Jonathan, in my experience the Release against Release comparison is hugely in favor of Xamarin.Forms.
Microsoft MAUI .NET 7 and .NET 8 update notes always refer to improvements (in tests) against previous MAUI versions,
The sad thing is I like MAUI coding. I don't like the result, and the ugly tweaks I do to keep layouts intact, more or less, when the screen orientation changes.

[anpin]

@mikebikerider the link you posted seems to be private

[mikebikerider]

I changed the repository to public. Thank you for pointing it out.