Skip useless handler mappings calls while connecting #27259

albyrock87 · 2025-01-21T17:43:55Z

Description of Change

This is an alternative initial version of #27042.
Everything has already been explained there.

Based on/includes #28077 PR

Credits to @MartyIX to have explored the effectiveness of skipping specific mappers.

Key differences from the other PR:

Avoid pre-mapping defaults: if the developer replaced the mapper and we skip execution, we're also skipping their custom code which would bring them wonder why their code it's not working while it should be
Adds easy-to-use extension methods to IElement and IElementHandler to get the handler state
We can selectively skip native calls close to them and by platform (for example on iOS MappingFrame takes care of all the coordinates, even translations, while on other platforms the situation is different)

Benchmark using Nalu Weather app

https://github.com/nalu-development/nalu/tree/main/Samples/Nalu.Maui.Weather

Click on the links in the table to download the speedscope.json file.

Platform	`SetVirtualView` (SR4)	`SetVirtualView` (PR)	Improvement
iOS	411.99ms	233.62ms	43%
Android	340.62ms	299.34ms	12%
Windows	1.94s	1.50s	22%

Thanks to @MartyIX for collecting speedscopes on Windows!

Benchmark (from CI - on iOS UI tests)

Note: there is some variability in the benchmark caused by the runner itself, but looking at many recent PRs, main branch never goes under 2600ms.

main branch

#27042 original PR

this PR

Issues Fixed

Fixes #17303

PureWeen · 2025-01-21T18:26:47Z

/azp run

azure-pipelines · 2025-01-21T18:27:10Z

Azure Pipelines successfully started running 3 pipeline(s).

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

PureWeen · 2025-01-23T22:40:16Z

/azp run

azure-pipelines · 2025-01-23T22:40:37Z

Azure Pipelines successfully started running 3 pipeline(s).

MartyIX · 2025-01-24T10:33:58Z

src/Core/src/Handlers/InternalElementHandlerExtensions.cs

+		internal static bool IsMappingProperties(this IElementHandler handler) =>
+			(handler as IElementHandlerStateExhibitor)?.State.HasFlag(ElementHandlerState.MappingProperties) ?? false;


The method as-is is user-friendly. However, the result is perhaps unexpected when handler is not IElementHandlerStateExhibitor. In that case, I would expect to get null (and not false) as it would tell me "perhaps the handler is actually mapping properties but it does not provide the information". Though, I'm aware that that might lead to less friendly API.

Anyway, feel free to ignore if you feel like it does not add any value.

This is only temporary for .NET9, and the ?. is there for type safety.
Hopefully these methods will be public and moved to IElementHandler in .NET10.

src/Core/src/Handlers/Border/BorderHandler.cs

bcaceiro · 2025-01-30T08:57:59Z

Is this already available in nightlies?

marcojak · 2025-01-30T09:10:00Z

Definitely it would be good to try it.

Great to see attention to the performances as MAUI struggles a lot there.

albyrock87 · 2025-01-30T09:11:32Z

Is this already available in nightlies?

Try this out and let us know: 9.0.40-ci.main.25073.66

bcaceiro · 2025-01-30T11:43:50Z

@albyrock87 just tried the latest nightly, everything seems smooth! ( only tested so far on Android)

PureWeen · 2025-01-30T12:37:31Z

@albyrock87 just tried the latest nightly, everything seems smooth! ( only tested so far on Android)

do you have a repro I can test against to compare before and after this PR?

Or possibly a video of what you mean by "everything seems smooth"?

bcaceiro · 2025-01-30T17:16:38Z

@PureWeen not really, since my app is quite complex (ble, views, etc) I haven't still recorded a speedscope, so it is really just more a "feeling" than any measurable data. In debug mode, and release mode, it seems the loads are a bit faster in pages Appearing, not dramatically faster, but seems faster.

Once I have opportunity I will try to record something though

albyrock87 · 2025-01-30T18:04:17Z

@bcaceiro if you record the speedscopes for comparison, you should check timings on SetVirtualView method.

bcaceiro · 2025-02-04T15:17:12Z

Update: this is not available on nightlies. So I really didn' test this PR in my previous "feeling".
Nevertheless, now I have sucessfully configured manually the downloaded Nuget, and yes, now it is noticeable in a page with a collectionview, labels and 2 buttons, the difference in the render ( in debug mode). I haven't recorded a speedscope since I'm having some issues with VSCode.

OvrBtn · 2025-02-04T15:36:02Z

@MartyIX If I remember correctly in case of this page most of the delay is thanks to CollectionView and ContentPresenter but maybe it will be useful somehow
https://github.com/OvrBtn/MAUIPerf/blob/master/MAUIPerf/Views/CollectionView1Page.xaml

If you want I can try to create some example based more around changes in this PR but from what I've seen you already have one.
(Testing on real device (Samsung Galaxy A50, release config)

version
video	v30.mp4	v40.mp4

azure-pipelines · 2025-02-26T14:01:20Z

Azure Pipelines successfully started running 3 pipeline(s).

src/Core/src/PropertyMapper.cs

PureWeen · 2025-06-25T20:06:02Z

/azp run

azure-pipelines · 2025-06-25T20:06:29Z

Azure Pipelines successfully started running 3 pipeline(s).

PureWeen

Test failures on this one seem accurate

bhavanesh2001 · 2025-06-26T19:27:51Z

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

 		/// <param name="view">The associated <see cref="IView"/> instance.</param>
 		public static void MapFlowDirection(IViewHandler handler, IView view)
 		{
+			if (handler.IsConnectingHandler() && view.FlowDirection == FlowDirection.MatchParent) return;


This is preventing FlowDirection propagation to child view

Since now path wont make it to this

maui/src/Core/src/Platform/iOS/ViewExtensions.cs

Line 121 in 3d584fa

updateValue = GetParentMatchingSemanticContentAttribute(view);

Related failing test : EntryClearButtonWorks

Thanks, apparently UIKit is the only one not having an automatic MatchParent behavior, so I'm gonna skip this check if it's IOS || MACCATALYST.

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

MartyIX · 2025-06-27T12:21:09Z

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

+				return;
+			}
+#else
+			if (handler.IsConnectingHandler() && double.IsNaN(view.MinimumWidth)) return;


@albyrock87 This should not be on Windows to fix the check box test.

PureWeen · 2025-06-27T14:25:57Z

/azp run

azure-pipelines · 2025-06-27T14:26:25Z

Azure Pipelines successfully started running 3 pipeline(s).

* Skip useless initial handler mappings calls * Apply suggestions from code review, fixes check on Maximum* * Windows: automation properties are extremely costly * Fix broken UI tests * Workaround Windows broken tests --------- Co-authored-by: MartyIX <203266+MartyIX@users.noreply.github.com>

albyrock87 requested a review from a team as a code owner January 21, 2025 17:43

albyrock87 requested review from PureWeen and rmarinho January 21, 2025 17:43

dotnet-policy-service bot added the community ✨ Community Contribution label Jan 21, 2025

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albyrock87 force-pushed the skip-useless-initial-handler-mappings-calls branch from 5573017 to 893e551 Compare January 22, 2025 20:29

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albyrock87 force-pushed the skip-useless-initial-handler-mappings-calls branch from 893e551 to 21694d0 Compare February 26, 2025 12:13

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albyrock87 force-pushed the skip-useless-initial-handler-mappings-calls branch 3 times, most recently from 69a569a to f15369c Compare February 28, 2025 13:48

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Apply suggestions from code review, fixes check on Maximum*

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Windows: automation properties are extremely costly

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Fix broken UI tests

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albyrock87 mentioned this pull request Jul 23, 2025

StackLayout performance degrades in .NET MAUI (1s) vs Xamarin (0.5s) with 100+ labels in Release Mode #30721

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		internal static bool IsMappingProperties(this IElementHandler handler) =>
		(handler as IElementHandlerStateExhibitor)?.State.HasFlag(ElementHandlerState.MappingProperties) ?? false;

Skip useless handler mappings calls while connecting #27259

Skip useless handler mappings calls while connecting #27259

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albyrock87 commented Jan 21, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description of Change

Benchmark using Nalu Weather app

Benchmark (from CI - on iOS UI tests)

Issues Fixed

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PureWeen commented Jan 21, 2025

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