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Instruments is a performance-analysis and testing tool for iOS, iPadOS, watchOS, tvOS, and macOS apps.

Instruments Documentation

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Memory leak in SwiftUI when pressing keys (detected by instruments)
I've discovered what appears to be a system-level memory leak when pressing any key in Swift UI projects. This issue occurs even in a completely empty SwiftUI project with no custom code or event handlers. When monitoring with Instruments' Leaks tool, I observe multiple memory leaks each time any key is pressed. These leaks consist primarily of: NSExtraData objects (240 bytes each) NSMenuItem objects (112 bytes each) Other AppKit and Foundation objects Has anyone else encountered this issue? How can I fix this behavior? While the leaks are small (about 5-6KB per keypress), they could potentially accumulate in applications where keyboard input is frequent.
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Mar ’25
Processor Trace not Working on C/C++ Console Apps
Hi, When I run the new Processor Trace instrument on a simple C or C++ console app, it hangs in "Analyzing - Transferring data" upon finishing the measurement. When I run it without any other instrument, I get the error: Failed to stop recording session: Data Providers emitted errors: CPUTrace Any ideas what I could try, or how to get a more verbose log of this failure? Best, Ronny P.S.: I'm using a Macbook Pro M4 Pro 14". MacOs Version 15.4 Beta (24E5228e)
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Mar ’25
Understanding power usage on a macOS app
It looks like, for some reason, our apps are using a bunch of power sometimes. sysdiagnose has this in the power log: Never mind. Including the output of sysdiagnose has "sensitive language," and it won't tell me what is sensitive, making this a waste of my time. ETA: Ok, I I can attach the file: power.log I've gone through the energy documentation, but it seems geared towards embedded, not macOS, so I'm not sure how I can figure this out more. The extra problem, of course, is that we have a network extension, two daemons, and a GUI app. 😄
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Mar ’25
Instrument Recording Failure - CPU counter failed
Hi, I’m encountering an issue while using xctrace & instruments to profile an application on macOS. Specifically, when trying to record a trace using the CPU Profiler template, I get the following errors: Failed to start the recording: configureHardwareCounters: Failed set kpc configuration: Operation not permitted. Unexpected failure: Couriers have returned unexpectedly. macOS Version: 15.3.1 Chip: Apple M4 Pro Xcode Version: Xcode 16.2
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Mar ’25
Instruments has an error and a typo
* [Error] Failed to stop recording session: Failed stoping ktrace session. (xcode-select version 2409) So why can't it stop the ktrace session? And how long has that typo been around? 😄 (Look, I've kept typos in log messages for years because it differentiated that message from other messages.)
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Feb ’25
Configuring "high frequency sampling"
Hey folks, We are looking for a way to increase the sampling frequency beyong what's currently called "high frequency sampling" for CPU profiler (or time profiler -- doesn't really matter for us). We are aware that this is not offered through the UI but wondering if we can somehow experimentally enable this via the .tracetemplate (plist). Basically, we see that samplingRate exists (in the plist) but don't see it having an effect on the actual runs. The resulting trace file always lists sample-rate-micro-seconds="1000" for the data table. E.g., <table trigger="time" pmc-events="Cycles" target-pid="SINGLE" schema="counters-profile" needs-kernel-callstack="0" sample-rate-micro-seconds="1000"/> Cheers
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Feb ’25