Deferring Data Analysis to Increase Accuracy for All Trace Documents

Increase the accuracy of performance-related data by deferring data analysis until you quit the application you are testing. Performing analysis live slows down the target process by taking up CPU time and memory, which leaves you with measurements that may not reflect how the process would normally behave.

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To defer data analysis to increase speed and accuracy for all trace documents
  1. Choose Instruments > Preferences.

  2. In the General tab, select the “Always use deferred mode” checkbox.

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In its default mode, Instruments analyzes and displays data while your app is profiled—allowing you to view the data as it is collected. Setting this option in Preferences changes this default behavior to make Instruments run in deferred mode. Deferred mode delays the analysis of data until the data collection is done, either after your app has finished running or after you click Stop. During data collection you are blocked from interacting with the instruments that are collecting data.

In deferred mode, after data collection is complete, Instruments processes the data and displays it on the screen. Deferring the data analysis adds time after the data collection process, but it helps ensure that performance-related data is accurate.

Definitive Discussion