ncreated
commented
1 year ago Hey @DCleymans 👋. Thanks for sharing insights. While Session Replay is in Beta we still work on improving the overall performance and this issue is something we will be definitely looking into.
In current state, the pressure on CPU highly links (basically O(n)) to the number of views presented on the screen. More views == more processing on background thread. To better understand the situation in your app, could you share an approximate number of UIViews your app displays while CPU pressure is high? Even sharing a screenshot (from app or replay) might be very handy.
When changing the interval in the
MainThreadScheduler(...). But I suppose this leads to less accurate session replays?
If changing the interval, the accuraccy of a single replay frame will be the same, but the frame-rate of a replay will be lower. In result, you'd experience less smooth Session Replay.
What can be done in order to lower the CPU load?
As for today, there isn't yet any configuration in public API that you could utilise to lower this impact. It might be best if we know the complexity of your UI, so we can implement more targeted optimisations on our side.
DCleymans
maciejburda
Using dd-sdk-ios develop branch (same results when using release 2.2.1 and release 2.1.1).
When we enable SessionReplay in our iOS app, the cpu load goes over 100% continuously. Our app consists of a splitViewController and can show different views as the second ViewController of the splitViewController. Some views have more content than others. When switching to a screen with less content, the CPU load drops, but never below 50%.
CPU load when showing a view with complex content:
CPU load when showing a view with simple content:
When pausing the running app, it looks like it is mostly doing work in a datadog thread: Thread 139 Queue : com.datadoghq.session-replay.processor (serial)
The cpu load drops to almost 0 when the app goes to the background. The app remains active, since it plays music when in background mode.
When changing the interval in the MainThreadScheduler to a larger value the cpu loads also drops. For example, change
let scheduler = MainThreadScheduler(interval: 0.1)tolet scheduler = MainThreadScheduler(interval: 1)the cpu load already drops to 15%.But I suppose this leads to less accurate session replays? What can be done in order to lower the CPU load?