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RUM Screens

The Screens tab measures per-screen performance across your app, so you can find the slowest or jankiest screens without knowing what to look for up front.

Total Screens, Slowest Screen, Most Janky, and Most Crashing stat cards above a table with Screen, Views, Unique Sessions, Avg Load, P95 Load, Avg Time Spent, Long Tasks, and Crashes columns

Screen List​

Four stat tiles summarize the whole app before the table: Total Screens, Slowest Screen (with its avg load time), Most Janky (with its long task count), and Most Crashing (with its crash count).

Table Columns​

ColumnDescription
ScreenThe screen's route/name
ViewsNumber of times the screen was viewed
Unique SessionsDistinct sessions that viewed it (links to a filtered session list)
Avg LoadAverage load time
P95 Load95th-percentile load time
Avg Time SpentAverage time users spent on the screen
Long TasksCount of long-running UI-thread tasks (jank)
CrashesCrashes that occurred on this screen

Sort by Avg Load or Long Tasks to find the screens most in need of optimization.

Screen Details​

Select a screen to see its full performance breakdown.

Summary Stats​

Views, Unique Sessions, Avg Load Time, P95 Load Time, Long Tasks, and Crashes stat cards

Views, Unique Sessions, Avg Load Time, P95 Load Time, Long Tasks, and Crashes for the selected screen and time range.

Load Time Trend and Views Over Time​

Load Time Trend chart and Views Over Time chart

  • Load Time Trend - Avg and p95 load time over the range, with a Name / Min / Mean / Max table
  • Views Over Time - view volume over the range

Rendering and Resource Usage​

Frame Build Time and Frame Raster Time charts

  • Frame Build Time and Frame Raster Time - how long each frame took to build (widget/layout work) versus rasterize (GPU work); sustained spikes in either indicate jank

Memory Usage and CPU Usage charts

  • Memory Usage - resident memory over time
  • CPU Usage - CPU utilization over time

Slowest Loads and Long Tasks​

Slowest Loads and Long Tasks (Jank Events) tables

  • Slowest Loads - table of individual slow page loads (Time, Load Time, User, Session)
  • Long Tasks (Jank Events) - table of individual long tasks (Time, Duration, User, Session)

Both tables link straight to the User and Session involved, and support Load more to page through additional rows.

Crashes on this Screen​

Crashes on this Screen table with Time, Error Type, Message, and Session columns

A table of crashes attributed to this screen (Time, Error Type, Message, Session), or "No crashes on this screen" when there are none in range.

Use Cases​

Finding the Slowest Screen​

  1. Check the Slowest Screen stat tile, or sort the Screen List by Avg Load
  2. Open the screen and check Load Time Trend for a gradual regression vs. a one-time spike
  3. Cross-check Slowest Loads for the specific sessions affected

Diagnosing Jank on a Screen​

  1. Check the Most Janky stat tile, or sort by Long Tasks
  2. Open the screen and compare Frame Build Time vs. Frame Raster Time to narrow down whether it's widget/layout work or GPU work
  3. Check Long Tasks (Jank Events) for the specific sessions and times
  • Getting Started - Interface layout and shared filters
  • Overview - Top Crashing Screens and Slowest Screens at a glance
  • ANR - Frozen-UI events grouped by screen
  • Sessions - Full session timeline for a specific view
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