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.

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!

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

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.

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?

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!

Hi :wave: I am not sure that I use it right, I was not able to profile using these events: I am on a M1 Pro machine using macOS 15.5. I just wonder if these events are support on Apple Sillicon.

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?

I am trying to perform swiftUI instrumentation on my ios app. whenever i hit the rocord button, the app launches on target device and closes with the error: Failed to start the recording: Failed starting ktrace session. How do i resolve this please?

Trying to examine performance issues in Xcode Instruments using the Animation Hitches instrument in Xcode 16.0 beta 6 (16A5230g). When connected to my iPhone 15 Pro Max and I try to start a run with my app, it has an error “Failed to split user provided arguments: working directory doesn't exist” with timestamp “(Before Run Started)”. When running the app on an iOS simulator, the instrument runs fine—but I want to profile on a real device.
 Instruments > Settings, Recording Location set to Default and that directory does exist.

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

When running instruments or when debug memory in Xcode, I am getting same error as An unknown error occurred launching the helper task Xcode: Xcode16.3 OS: 15.5 Beta (24F5068b) Mac mini: Apple M2 Pro

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.

When creating an icon using icon composer, I cant upload a build to testflight/App Store connect. Running on device from Xcode works fine, but as soon as I archive and upload to App Store Connect, I get an error saying the icon contains an alpha channel

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)