Reducing the % of branches missed can greatly improve app performance. Missed branches by the CPU are expensive and results in slower execution.
#Iswift view entire stack trace code#
To configure a formula, select the ⚙ icon and then Create Formula.īranch misprediction is one metric to determine how efficiently code is written. Formulas use events to compute a numerical result, for example, the % of branches missed on the chip. The best way to get high-value performance profiles from Counters is to use formulas. Additionally, we need to know the number of missed branches to compute the % of branches missed. The number of branches executed on the chip is not enough information by itself to find performance issues. With INST_BRANCH selected the performance profile may look something like this: Counters configured to count branch instructions Create Formulas Using Counters Using the + add specific events available on the CPU of the device you connected to Instruments. The examples presented in this post will sample by time. You'll see a menu show with configuration options for Counters: Counters Recording Options window To configure Counters, select File -> Recording Options from the Instruments navigation menu. This means the chip event options available on an A10 chip inside of an iPad may be different than the chip events available on an A12 chip inside of an iPhone Xs. Further, the Counters tool profiles events that are hardware-specific. Unlike other Instruments tools, Counters requires some configuration to provide valuable insights. For example, the event INST_BRANCH can be added to the Counters tool to count the number of branches executed by the CPU. Profile Apps With Xcode Instruments CountersĬounters is an Instruments tool used to profile low-level chip events in iOS and macOS apps.
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