Upgrade to Avalonia 11.0.0-preview6

[aldelaro5]

I am leaving this here because I tried to upgrade it and while everything seemed fine and builds, I am hitting a very bad performance issue which profiling seems to suggests that the GC is put under a lot of pressure which didn't happen with preview5. The CPU usage is much higher than it should and the app becomes very unresponsive.

Just in case I can't get anywhere so my branch is there.

[danipen]

Could you please share your profiling data? What are the hot paths?

[danipen]

How do you reproduce the bad performance? Do you experience it in your application or just in the AvaloniaEdit demo project?

[aldelaro5]

Could you please share your profiling data? What are the hot paths?

This is how I got there, I am unfortunately not experienced with profiling so I actually have a hard time figuring out where are the hot paths. Rider doesn't really show me something that jumps out to me. What I do know is the GC has a lot more pressure,
preview6:

preview5:

How do you reproduce the bad performance? Do you experience it in your application or just in the AvaloniaEdit demo project?

The demo project. I just needed to run it to see the issues, it's incredibly unresponsive immediately and all the time.

[danipen]

Quite good perf under windows for me ... Are you trying windows OS?

[danipen]

@aldelaro5 do you experience the same bad perf if you execute the application directly without the debugger?

[aldelaro5]

I am on arch linux, I have access to a windows vm I can try that later, but in digging more, I might have a hint after analysing more profiling:

This path is notably hot in preview 6, but not in preview 5. I also noticed the RunLoop has a lot of "lock contention" which sounds like this hot path could be stalling the UI thread?

It does seem to involve skia, maybe it's a linux specific issue?

[danipen]

Could be a linux specific issue, yes.
cc/ @Gillibald

[Gillibald]

Is MatchFamily called more often than TryCreateGlyphTypeface?

[aldelaro5]

Ok it seems to be an avalonia issue.

This pr AvaloniaUI/Avalonia#10455 is the one that seems to have introduced this problem because it seems if I try ci builds before this pr, the perf comes back, but if I try the ci build of this pr, it reproduces.

[aldelaro5]

Is MatchFamily called more often than TryCreateGlyphTypeface?

I think it's more saying that either MatchFamily is slow OR that it ends up being called using this path so much that this path as a whole is slow. Given the pr I posted above seems the most suspicious, it's most likely the later it seems?

[Numpsy]

fwiw, I've given it a try in both a Windows desktop app and in web assembly, and it seems to work ok, with perf about the same as the preview 2 release

[aldelaro5]

I just filed an avalonia issue about this because I noticed the same degradation in a completely different context. I can however confirm it doesn't seem to affect Windows so this seems to be a Linux specific issue.

[Numpsy]

So, is this perf issue a blocker to getting a preview 6 compatible AvaloniaEdit build released, or as the issue is in Avalonia can we still get a new build here whilst waiting for that? (I just think a new compatible build would be nice for testing other things is all(

[danipen]

LGTM

[danipen]

I think we can merge.

[Numpsy]

Thanks

[bouyeijiang]

The Linux mint system I am using also has the same issue, the window system is fine