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

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CPU Profiling with instruments fails to start
When trying to profile any process with the Instruments CPU Profiler I get this message: (Before run started) No allocated PMI record. Not sure what to do here. I tried other instruments like time profile and that works fine so not sure what to do here... Didn't find any people having similar issues when googling so I'm hoping someone here can help me out. Im using a m1 max 14 inch macbook pro with macOS 12.3 and instruments 13.0 (13A1030d)
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9.5k
Feb ’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
Using Processor Trace on Non-Xcode Built Binary
Hiya folks! I'm David and I work on rust-analyzer, which is a language server for Rust similar to sourcekit-lsp. I'm using the new Instruments profiling tooling functionality in Xcode 16.3 and Xcode 26 (Processor Trace and CPU Counters) to profile our trait solver/type checker. While I've been able to use the new CPU Counters instrument successfully (the CPU Bottleneck feature is incredible! Props to the team!), I've been unable to make use of the Processor Trace instrument. Instruments gives me the error message "Processor Trace cannot profile this process without proper permissions". The diagnostic suggests adding the com.apple.security-get-task-allow entitlement to the code I'm trying to profile, or ensure that the build setting CODE_SIGN_INJECT_BASE_ENTITLEMENTS = YES is enabled in Xcode. Unfortunately, I don't know how I can add that entitlement to a self-signed binary produced by Cargo and I'm not using Xcode for somewhat obvious reasons. Here's some information about my setup: Instruments Version 26.0 (17A5241e) I'm on an 14" MacBook Pro with M4 Pro. It's running macOS Version 26.0 Beta (25A5295e). I've enabled the "Processor Trace" feature in "Developer Tools" and even added the Instruments application to "Developer Tools". As a last-ditch effort before posting this, I disabled SIP on my Mac. Didn't help. To reproduce my issue: Get Rust via https://rustup.rs/. Clone rust-analyzer: git clone https://github.com/rust-lang/rust-analyzer.git. cd rust-analyzer Run cargo test --package hir-ty --lib --profile=dev-rel -- tests::incremental::add_struct_invalidates_trait_solve --exact --show-output. By default, this command will output a bunch of build progress with the output containing something like Running unittests src/lib.rs (target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe). I take the absolute path of that hir_ty-$SOME-HASH string (in my case, it looks like /Users/dbarsky/Developer/rust-analyzer/target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe) and add it to the "Launch" profile. To the arguments section, I add --exact tests::incremental::add_struct_invalidates_trait_solve. I then try to record/profile via Instruments, but then I get the error message I shared above. Below is output of codesign -dvvv: ❯ codesign -dvvv target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe Executable=/Users/dbarsky/Developer/rust-analyzer/target/dev-rel/deps/hir_ty-f1dbf1b1d36575fe Identifier=hir_ty-f1dbf1b1d36575fe Format=Mach-O thin (arm64) CodeDirectory v=20400 size=140368 flags=0x20002(adhoc,linker-signed) hashes=4383+0 location=embedded Hash type=sha256 size=32 CandidateCDHash sha256=99e96c8622c7e20518617c66a7d4144dc0daef28 CandidateCDHashFull sha256=99e96c8622c7e20518617c66a7d4144dc0daef28f22fac013c28a784571ce1df Hash choices=sha256 CMSDigest=99e96c8622c7e20518617c66a7d4144dc0daef28f22fac013c28a784571ce1df CMSDigestType=2 CDHash=99e96c8622c7e20518617c66a7d4144dc0daef28 Signature=adhoc Info.plist=not bound TeamIdentifier=not set Sealed Resources=none Internal requirements=none Any tips would be welcome! Additionally—and perhaps somewhat naively—I think I'd expect the Processor Trace instrument to just work with an adhoc-signed binary, as lldb and friends largely do—I'm not sure that such a high barrier for CPU perf counters is warranted, especially on an adhoc-signed binary.
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Sep ’25
iPhone 17, IOS 26 - No option to enable ‘Processor Trace’
According to the documentation for Processor Trace, it should be available on the iPhone 16 or later. Going off of the Optimize CPU performance with Instruments WWDC session, the toggle for it should be under Developer > Performance, but I don’t see this option anywhere on my iPhone 17. I can’t run a Processor Trace in Instruments without this feature turned on, because it claims my iPhone’s CPU is unsupported. Has anyone else managed to enable Processor Trace on the A19 chips?
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Oct ’25
XCTestCase Async Setup Function Always Causes Leak in Instruments
I'm developing a library and using XCTest for unit tests. While trying to profile the test suite, I noticed that Instruments seems to report a leak every single time the async throwing setup function is called, no matter what. For example, This will report a leak: final class LeakTests: XCTestCase { override func setUp() async throws { try await super.setUp() } func testLeak() async throws { try await Task.sleep(nanoseconds: 5_000_000_000) } } This will not report a leak: final class LeakTests: XCTestCase { // override func setUp() async throws { // try await super.setUp() // } func testLeak() async throws { try await Task.sleep(nanoseconds: 5_000_000_000) } } Any ideas on why this might be happening, or should I just file a bug report? It makes it quite difficult to use the leak detection for unit tests, as it shows hundreds of leaks when the whole suite is ran.
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Jan ’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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Apr ’25
Could not open Instruments Tutorials's project files
I am currently reviewing the tutorial documentation for the instruments. (Instruments Tutorials: https://developer.apple.com/tutorials/instruments/identifying-a-hang) It seems very useful, so I want to follow the tutorials step by step. However, I am having trouble downloading the sample project files; it appears that the 7z file is broken. (https://developer.apple.com/instruments/tutorials/downloads/InitialVersion.7z) Can anyone help me with how to download the project files properly?
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Apr ’25
Instruments Network: Background URLSession instance appears not to complete
As stated in the title. I am running the following code. Each time I perform an API call, I create a new instance of URLSession and use a background-configured session to allow background API calls. ` Code being executed: import Foundation // Model definitions struct RandomUserResponse: Codable { let results: [RandomUser] } struct RandomUser: Codable { let name: Name let email: String } struct Name: Codable { let first: String let last: String } // Fetcher class class RandomUserFetcher: NSObject, URLSessionDataDelegate { private var receivedData = Data() private var completion: ((RandomUser?) -> Void)? private var session: URLSession! func fetchRandomUserInBackground(completion: @escaping (RandomUser?) -> Void) { self.completion = completion let configuration = URLSessionConfiguration.background(withIdentifier: "com.example.randomuser.bg") session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil) let url = URL(string: "https://randomuser.me/api/" )! let task = session.dataTask(with: url) task.resume() } // Data received func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) { receivedData.append(data) } // Completion func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) { defer { self.session.finishTasksAndInvalidate() } guard error == nil else { print("Error: \(error!)") completion?(nil) return } do { let response = try JSONDecoder().decode(RandomUserResponse.self, from: receivedData) completion?(response.results.first) } catch { print("Decoding error: \(error)") completion?(nil) } } }` Called in viewDidLoad, etc.: let fetcher = RandomUserFetcher() fetcher.fetchRandomUserInBackground { user in if let user = user { print("Name: \(user.name.first) \(user.name.last), Email: \(user.email)") } else { print("Failed to fetch random user.") } } In Instruments' Network instrument, I focus on my app's process, use 'Command + 3', and switch to 'List: URLSessionTasks'. Even though didCompleteWithError is called and the API call fully completes, the Duration keeps increasing, and the Success column remains '-' (neither 'Yes' nor 'No'). For non-background URLSessions, the session shows up as 'unnamed session', but for background URLSessions, it appears as 'unnamed background session 1 (XXXXXX-XXXXXX-XXXXX)'. Does this mean the session is not actually being completed? I've checked Debug Memory Graph and confirmed there is no NSURLSession memory leak, but is it possible that the app is somehow still retaining session information internally? I also suspect that Instruments may not be able to fully track background URLSession tasks.
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Jun ’25
Instruments Time Profiler Call Stacks & Percentages Differ Between Xcode 16.0 (16A242d) and 16.3 (16E140) – How Can I Get Consistent Metrics?
I’m seeing inconsistent call stacks and usage percentages in the Time Profiler between two Instruments builds: • Xcode 16.0’s Instruments Version 16.0 (16A242d) • Xcode 16.3’s Instruments Version 16.0 (16E140) When I open an old .trace file recorded with the 16A242d profiler in the newer 16E140 Instruments, the call trees and percentage breakdowns no longer match. It looks like the latest Instruments now exposes or collapses different frames (e.g. system libraries, inline code) by default. I rely on these call stacks as a baseline to track performance regressions and verify optimizations over time. Unfortunately, every Xcode/Instruments update changes what I see, making it impossible to compare profiles across versions. My questions: Is there a way in Instruments 16.0 (16E140) to restore the exact call-tree view and percentage calculations that 16A242d produced? Failing that, is there a recommended workflow or tool for capturing CPU profiles in a way that remains stable and comparable, regardless of Xcode or Instruments version? Any guidance on achieving consistent, version-independent performance measurements would be greatly appreciated!
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Jun ’25
Instruments Failure in Xcode 16.4
Updated Xcode from 16.2 to 16.4, running Time Profile in Instruments, it launches the trace, but does not install or load on connected device, breaks the functionality. I am unable to debug... ERROR: Connection with the remote side was unexpectedly closed : <dictionary: 0x1f3c8b6d0> { count = 1, transaction: 0, voucher = 0x0, contents = "XPCErrorDescription" => <string: 0x1f3c8b850> { length = 22, contents = "Connection interrupted" } } Domain: IXRemoteErrorDomain Code: 6 User Info: { DVTErrorCreationDateKey = "2025-08-09 00:47:53 +0000"; } -- Connection with the remote side was unexpectedly closed : <dictionary: 0x1f3c8b6d0> { count = 1, transaction: 0, voucher = 0x0, contents = "XPCErrorDescription" => <string: 0x1f3c8b850> { length = 22, contents = "Connection interrupted" } } Domain: IXRemoteErrorDomain Code: 6 IOS 18.5
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260
Aug ’25
How do I capture localhost traffic in instruments?
I'm currently exploring Instruments for profiling and tracing on macOS 15.6.1. I know there is the "network connections" instrument which records TCP/UDP information, however it seems to not include the "lo0" (loopback) interface. Is there a way to configure it so that localhost traffic is included in the recording? as the application I'm tracing uses that and I want that information to be included in traces. The documentation for network-interface-detection schema makes no mention of how it detects interfaces. Thanks in advance.
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Sep ’25
Where is the instruments command line tool?
I was reading through this documentation about instruments command line tool https://help.apple.com/instruments/mac/current/#/devb14ffaa5 and how it can be launched from the command line. However, unlike what the documentation states, there's no such instruments command anywhere on my macos M1 (OS version 15.6). That command gives: $> instruments zsh: command not found: instruments I do have XCode installed which has the Instruments.App (GUI app) but not the command line utility: $> ls Xcode.app/Contents/Applications/ ... Instruments.app Is that linked documentation up-to-date (it does say "latest" in the URL)? Is there some other way to install this command line utility?
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Aug ’25
Accessing Built-In iOS Alarm Sounds When Using AlarmKit
Hi everyone, I’m currently integrating AlarmKit into an app and would like to offer users the same selection of built-in iOS alarm sounds that the native Clock app provides. So far, I haven’t found any API in AlarmKit (or elsewhere in the SDK) that exposes the system’s default alarm tones. Before implementing a custom sound library, I wanted to check: Is there any way to access or present the iOS system alarm sounds when creating alarms with AlarmKit? Or are developers limited to custom audio files that we provide ourselves? If anyone has experience with AlarmKit or knows whether this is technically possible (or explicitly restricted), I’d really appreciate your insights. Thanks!
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Dec ’25
Instruments Crash using swiftui instrument
Instruments is crashing when the swiftui instrument is stopped (the session is finished) and the transfer begins from device to device: Crashed Thread: 11 Dispatch queue: com.apple.swiftuitracingsupport.reading Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Termination Reason: Namespace SIGNAL, Code 4 Illegal instruction: 4 Terminating Process: exc handler [1633] I've tried removing derived data, reinstalling xcode, updating xcode (I originally thought this might be the issue -- I needed to update to 26.2 from the 26 RC -- the update didn't fix crash or change the crash report), and restarting both devices. I'm running Instruments/Xcode 26.2 on a MacBook Pro 15" (2018) running Mac OS 15.7.2 (24G325) with an iPhone 16 Pro Max running 26.2. Hoping someone else might have seen this or could help me troubleshoot. I find the swiftui instrument be helpful and like to use it :) I can post a complete crash report as well.
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Change recording mode when using xctrace
Hey, In the UI of the Instruments app, I can change the recording mode to immediate. Is that possible when using xctrace? It seems to use deferred as a default. I've tried to create a template, set the recording mode to immediate, and use that template for recording. However, that doesn't seem to work. At least the exported TOC of the .trace will have the following summary: <summary> <start-date>2025-01-11T13:00:11.365+01:00</start-date> <end-date>2025-01-11T13:00:30.525+01:00</end-date> <duration>19.160279</duration> <end-reason>Target app exited</end-reason> <instruments-version>16.0 (16A242d)</instruments-version> <template-name>core_animation_fps</template-name> <recording-mode>Deferred</recording-mode> <time-limit>12 hours</time-limit> </summary> This issue might be related to: https://developer.apple.com/forums/thread/735948 Thanks a lot!
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Jan ’25