CPU Usage Instrument

The CPU Usage instrument captures information about the app's load on the CPU. It can record information from multiple threads when the Record thread information profiling preference is enabled.

Expanding the timeline reveals each thread's CPU load.

Discussion

Use the information captured by this instrument to inspect your app's general CPU usage, as well as debug CPU peaks and high usage.

Enable the Record thread information profiling preference to capture information about the threads in your app. Enable the Collect stack traces and Symbolicate stack traces to collect the heaviest thread's stack trace and symbolicate symbols to assist in debugging of your app's CPU load.

For an in-depth look at the profiling preferences, see Profiling Preferences.

Detail Pane

The detail pane includes your app's CPU usage at the time of the sample. If the Record thread information profiling preference was enabled during recording, the heaviest thread will also be noted for each sample.

Samples will be highlighted in red (warning 3) when:

• The main thread CPU load is above 90%
• The overall CPU load is above 200%

Samples will be highlighted in orange (warning 2) when:

• The main thread CPU load is above 80%
• The overall CPU load is above 150%

Samples will be highlighted in yellow (warning 1) when:

• The main thread CPU load is above 70%
• The overall CPU load is above 100%

Inspector Pane

For each sample, the inspector pane shows the time of the sample and the CPU usage. If the Record thread information profiling preference was enabled during recording, the inspector pane will display a threads breakdown pie chart and a list of the most active threads. If the Collect stack traces profiling preference was enabled during recording, the inspector pane will display the heaviest thread's stack trace.

You can select the one or more stack trace symbols and copy them in a debugging-friendly format for further investigation, symbolication, etc.