Profile Blazor WASM using Mono log profiler

[Chris-D-Turk]

AFAIK there's currently no built-in option to profile Blazor WASM apps (cpu sampling). see #76316
But as Blazor WASM uses a Mono Runtime it should be possible to use the Mono log profiler?!
The devs of Uno WASM somehow managed to do this: https://platform.uno/blog/uno-platform-4-1-30-perf-boost-android-12-net-6-mobile-preview-13-and-more/

But I don't know how to pass the necessary arguments to the runtime environment:
--profile=log:sample,output=xxx.mlpd

Is there any way to start a Blazor App with Mono arguments?

[javiercn]

@Chris-D-Turk thanks for contacting us.

@lewing is there a reasonable way in which we can enable this scenario?

[mkArtakMSFT]

Ping @lewing

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 7 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[lewing]

The runtime supports this but the current tooling story is around enabling eventpipe/eventsource so this isn't a supported scenario and you'd be on your own to get it working. We're doing some planning in the next few weeks and it is possible that this could change, I'll let everyone know if it does.

[Chris-D-Turk]

@lewing Thanks for your feedback.
I really hope you understand that good profiling tools are essential for developing production-ready applications.
We are currently evaluating whether to use Blazor WASM for our next project and the absence of profiling tools is a big drawback.
Allowing/Enabling us to use the existing Mono Profiler would be a quick win in my opinion.
Edit: Because you wrote "The runtime supports this" I looked a bit into it and yes - maybe not so "quick" :| There are obviously some problems to solve - like that there is no "real" filesystem to write the profile.mlpd to. But I will try to find a solution.

[Chris-D-Turk]

I managed to enable the profiler by invoking mono_profiler_init_log. But unfortunately the runtime crashes here: https://github.com/mono/mono/blob/main/mono/mini/mini-wasm.c#L495
So it looks like the log profiler is not really supported in mono-wasm :(

[ghost]

Tagging subscribers to 'arch-wasm': @lewing
See info in area-owners.md if you want to be subscribed.

Issue Details

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AFAIK there's currently no built-in option to profile Blazor WASM apps (cpu sampling). see #76316
But as Blazor WASM uses a Mono Runtime it should be possible to use the Mono log profiler?!
The devs of Uno WASM somehow managed to do this: https://platform.uno/blog/uno-platform-4-1-30-perf-boost-android-12-net-6-mobile-preview-13-and-more/

But I don't know how to pass the necessary arguments to the runtime environment:
--profile=log:sample,output=xxx.mlpd

Is there any way to start a Blazor App with Mono arguments?

Author:	Chris-D-Turk
Assignees:	lewing
Labels:	arch-wasm, untriaged
Milestone:	-

[jacob-l]

Hi @Chris-D-Turk , @lewing ,

What is the status of this issue? Is there any way to pass arguments to environment?

[pavelsavara]

I implemented browser profiler based on mono profiler here #77449
There is also HOWTO-use in the PR description.

[pavelsavara]

Closing this in favor of #72870