Add Profiling (Lite) functionality

[bitsandfoxes]

This is more like a brain-dump than an actionable issue for now. Feel free to chime in.

In an ideal world, we'd ship with a profiler, and have detailed and granular insights as part of the offering. But that's technically somewhat unfeasible and there the issue with performance overhead.
Additionally, the profiler is part of the Editor and developers typically profile on their machine.

Instead, what we could look into are general bottlenecks.

Unity has a fixed execution order of systems. What we could do here is hook up into this life-cycle and time it. This would allow us to answer general questions like

• How much time is spent on rendering each frame?
• How much time is spent on physics?
• How much time is spent on updating the game logic (user code - all update-calls combined)

That, combined with the context that the SDK is already collecting (i.e. device/OS) would already provide valuable insights.

[bruno-garcia]

But that's technically somewhat unfeasible and there the issue with performance overhead.

It's technically possible, but yeah it's high risk with the overhead sensitivity of games

Additionally, the profiler is part of the Editor and developers typically profile on their machine.

Right, the existing profiler in its current form only exists in the editor. But we could build our own (since afaik Unity's isn't open source and we can't fork/built on top of it)

The proposal makes sense but how is it related to Profiling?
Could we offer this functionality based on spans and span-metrics?

[bitsandfoxes]

Since these would be "per frame"-measurements, I don't think pure spans are the way to go. We could aggregate and add them as span-metrics over bigger periods of time. With spans and transactions we're always running into the question of when/where to start and finish.

I'm thinking about this more as a OOTB feature that is providing something like vitals. Ideally, those could be associated with sessions and releases. Users could observe trends that way too.

[bruno-garcia]

We could aggregate and add them as span-metrics over bigger periods of time. With spans and transactions we're always running into the question of when/where to start and finish.

👍 or keep a span around to use it to track the metric and flush when the game closes or something. It's hard with span metrics I'm afraid. Yeah what you said makes sense.

I'm thinking about this more as a OOTB feature that is providing something like vitals. Ideally, those could be associated with sessions and releases. Users could observe trends that way too.

Vitals today are based on transactions. We do need something that starts and ends. And it has a start/end timestamp so if we hack to be whole game duration that is probably going to look messy in the product.

[bitsandfoxes]

This might be something for Metrics indeed, see getsentry/sentry-docs#15178