Significant performance regression between 5.1.0 and 5.2.1

[database64128]

Bug explanation

After releasing a new version of my app with MaterialDesignThemes 5.2.1, a user reported that the UI would hang after some activity. Upon investigation, it became clear that the hang was caused by frequent content updates to the log viewer TextBox overloading the UI thread. The relevant logic in my app did not change between releases, so I tested older versions of MaterialDesignThemes. Reverting to version 5.1.0 resolved the issue. The UI no longer hangs.

While there are certainly optimizations I can make in my app, this performance regression in MaterialDesignThemes also deserves attention. I attempted to capture a CPU profile during the unresponsive state, but 87% of the CPU time was spent inside ReactiveUI.IReactiveObjectExtensions.RaiseAndSetIfChanged, which was not helpful for pinpointing the cause.

In case anyone wants to look at the CPU profile: youtube-dl-wpf-ui-hang.diagsession.zip

Possibly related: #3840.

Version

5.2.1

[corvinsz]

@database64128 while this isn't fixing the issue itself, and I'm not sure if you can/want to, but have you considered using a ListBox to output logs? It comes with (UI) virtualization enabled by default and can handle multiple thousand items no problem.

[corvinsz]

@database64128 in the .diagsession dump you provided 85,31% of the total CPU time was calling System.Windows.Controls.TextBox.get_LineCount().
PR #3874 could be a possible fix for this issue.
Could you download the latest prelease of this library and check if the problem persists?

[database64128]

while this isn't fixing the issue itself, and I'm not sure if you can/want to, but have you considered using a ListBox to output logs? It comes with (UI) virtualization enabled by default and can handle multiple thousand items no problem.

@corvinsz Thanks for the suggestion! Yes I have considered switching, but decided against doing so, because I don't want to lose the ability to select many lines of log messages. I'm more of a terminal person, and I want the log viewer to behave more like a terminal 😄

[Keboo]

@database64128 are you able to test with the latest 5.3.0 preview NuGet package to see if #3874 does solve the issue it resolves the performance issue?

[database64128]

After upgrading to 5.3.0-ci1132, the UI is now as responsive as with 5.1.0. I guess now the question is, when will 5.3.0 be released?

[Keboo]

After upgrading to 5.3.0-ci1132, the UI is now as responsive as with 5.1.0. I guess now the question is, when will 5.3.0 be released?

I am going to try and get it out this weekend. So stay tuned.