Comment by buzzerbetrayed
2 days ago
That was my initial thought as well. Anyone know what native screen loads typically are? I’m sure it varies wildly between apps, but 500ms seems like it would be on the slower end of a “fast” app.
2 days ago
That was my initial thought as well. Anyone know what native screen loads typically are? I’m sure it varies wildly between apps, but 500ms seems like it would be on the slower end of a “fast” app.
It really depends on what a "screen load" means exactly. If its just rendering the screen from some client-side data then I would expect something <16ms. To support 120fps displays, it would need to be <8ms.
If a "screen load" includes making a network request to fetch data, then this is a very weird metric to include in a post about React Native. Most of that time budget should just be waiting for the request to complete. Just as before, it should take <16ms to render the screen once the data arrives.
> Anyone know what native screen loads typically are?
500ms sounds about right for a cold launch but otherwise is pretty poor.
50-100ms for "minor" screen changes and 100-200ms for "major" ones are otherwise reasonable for native screens.
For typical apps, the four variables here are backend latency, network latency, client-side deserialization, and client GUI rendering. (Less commonly, apps which have complex client-side state will also spend time reconciling server and client state.)
Keeping UI rendering under 16ms is the gold standard for native apps. That leaves only deserialization as the other target which the mobile developer can optimize. However, the typical solution there involves convincing the backend to ship a different format (i.e. switching from JSON to binary PList or to SQLite DB file).
> Keeping UI rendering under 16ms is the gold standard for native apps.
No, it isn't.
If you're not including the actual rendering, so the actual code of the app only or at least only the code on the UI thread, the targets are much smaller. More like 3-6ms/frame.
If you're including rendering then pipelining and 90hz+ being common still changes that anyway.
> Keeping UI rendering under 16ms is the gold standard for native apps.
Not since they’ve started releasing 120hz screens.
For reference, our app is 100% in Jetpack Compose, our screen rendering for both cold and warm are in the average of ~460-480ms. App start is around ~480ms.
If your warm and cold starts are that close I'take a closer look at your measurement methodology. Could be your cold starts are actually warm, or your timing is starting late.