Frame Navigation leaks memory.

[Noemata]

Steps to reproduce the bug

App1.zip

Steps to reproduce the behavior:

1. Build attached app.
2. Run app.
3. Change pages using Go xxx Page buttons
4. Watch memory growth using Task Manager

Expected behavior
Memory should be reclaimed.

Screenshots
n/a

Version Info

NuGet package version:
[Microsoft.UI.Xaml.2.6.0-prerelease.210315002]

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
October 2020 Update (19042)	Yes

Device form factor	Saw the problem?
Desktop	Yes

Additional context

[Noemata]

https://social.msdn.microsoft.com/Forums/windowsapps/en-US/6a90654b-eb7c-44de-af6b-04140b0ee6ca/uwp-page-navigation-memory-leak?forum=wpdevelop

[StephenLPeters]

@Noemata do you know if this is a regression with 2.6 or if it was present in 2.5 as well? If you call GC.Collect mannually does it fix the leak?

[asierpn]

@Noemata in my tests by removing the TabView and setting NavigationCacheMode = Disabled the memory seems to stay below 225 MB, but if you set NavigationCacheMode = Enabled the memory keeps growing, in this case it is the DataGrid that is causing the memory leaks with NavigationCacheMode = Enabled.

This scenario must be tested using all WinUI controls.

[asierpn]

@Noemata at this moment you have the same questions that we have about UWP performance, there is memory leaks using NavigationCacheMode="Enabled" and there is also a delay when switching pages which we don't understand if all the visual tree of the page is cached. This delay increases when the visual tree of the page is big and also when the process is consuming so much memory caused by memory leaks, in low powered machines these delays are very noticeable, and if you stress the app during them you can crash it, this scenario can be easily reproduced with the XAML Controls Gallery official app.

I'll leave it to you to hound Microsoft on that one. I'm pretty sure they're sick of me already. @asierpn, suggest you file a separate issue for DataGrid with the sample below.

I hope they are not fed up with you, this feedback is necessary to improve the platform even if it is not pleasant to hear.

We don't use the DataGrid of the Windows Community Toolkit in our production app, I used it in this repro project to show you better our real scenario, we use a 3rd party DataGrid which has the same issue and we have reported it to our UWP controls provider.

[asierpn]

@Noemata It seems that Microsoft was aware of these issues for a long time and finally they have started to address them, at least the memory leaks: https://github.com/microsoft/CsWinRT/releases/tag/1.2.0.210402.1

And the issue with the delays navigating to cached pages must be directly related to #1633 and #3335, this other issue must be priorized.

[asierpn]

@Noemata your last results are very interesting, it is really hard to work with this kind of issues when VS is interfering in the tests, but still must be there some issues with frame navigation and memory leaks, open the official XAML Controls Gallery and navigate to each page, you will see how memory usage grows and render performance decreases, if the application is stressed it finally crashes.

I've to do more tests on my production app where we have navigation memory leaks to determine which controls or code is causing it.

[asierpn]

@Noemata I'm agree with you, I will restart all my tests to try to find what is causing the memory leaks in our app, your last sample is a good point to start, running it always outside VS.

[Noemata]

The following testing tool is mostly self explanatory if you have a close look at the code: https://github.com/Noemata/RosettaNavigation

The tool may be used to test both performance and Navigation Frame memory issues for both WinUI and UWP.

[lukedukeus]

Somehow, this is still an issue, on windows 11 22000, winui 1.1 preview 3

[CalebPowell57]

@Noemata I'm running into this issue and wonder if you've found any workaround or solution? I've tried different target versions, different uwp versions. I've even tried not using frame navigation, but instead, setting the content of a page to another page. In each scenario, it seems on general render, memory is leaked.

[github-actions]

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