We have 2 iPhones (16 pro - iOS 18.2, 16 regular - iOS 18.5 ) in single app mode and sometimes we need to shut them down manually. After holding Power and VolumeUp, shutdown screen appears as usual, but the slider isn't responding to touch, as well as the whole screen. After force restart using volume buttons, this issue disappears, but reappears after next phone restart.
If we disable single app mode -the issue is gone and touch screen works every time on shutdown screen. Both iPhones share the same behavior.
Is there any other way to reliably shut down the iPhone locally without using MDM or a way to fix this issue?
Instruments
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According to the ARM documentation for the CPU models available in Apple Silicon, the CoreSight implementation includes an Embedded Trace Macrocell which can perform a complete "Instruction Trace" (https://developer.arm.com/documentation/102119/0200/What-is-trace-). Although other operating systems such as Linux make this easy, we have not been able to find any tools or even a system-level API for accessing this feature of the ETM.
In the "Instruments" window of Xcode 16+, there is a "Processor Trace" instrument, but this performs sampling and is totally unrelated to the Instruction Trace we need for debugging and analysis purposes. Because it produces a complete, contiguous sequence of branch instructions, the Instruction Trace is essential for identifying precise execution behaviors that are otherwise invisible to the developer. On other platforms, an alternative is debugger scripting, but we have found far too many bugs and reliability issues with the macOS implementation of lldb.
Any suggestions would be greatly appreciated!
Topic:
Developer Tools & Services
SubTopic:
Instruments
I tried using Create ML of Xcode 26.0 beta 7 to generate a model using the "Word Tagging" template, and I received the error: Training progress unavailable - Unexpected error.
Using Create ML of XCode 16.4 with the same documentation, I was able to build the model and use it in a test app.
I'd like to understand why Create ML of Xcode 26 no longer works.
Topic:
Developer Tools & Services
SubTopic:
Instruments
Hello Apple team,
I am using xctrace to record an Allocations trace on iOS. For example:
xctrace record
--template "Allocations"
--launch com.example.myapp
--time-limit 30s
--output alloc.trace
After recording, I can export the results in Allocations List format (flat list of allocations) using:
xcrun xctrace export --input ./alloc.trace --xpath '/trace-toc/run/tracks/track[@name="Allocations"]/details/detail[@name="Allocations List"]' --output ./alloc.xml
This works fine and produces an XML output.
However, what I really need is to export the data in Call Tree format (as shown in Instruments GUI). I checked xctrace export --help, but it seems that the Allocations template only supports the List view for export, not the Call Tree breakdown.
My question is:
👉 Is there a way to export an Allocations trace in XML with Call Tree details using xctrace?
👉 If not, is there an API or recommended workflow to automate this instead of exporting manually from Instruments GUI?
Thanks in advance for your help!
Topic:
Developer Tools & Services
SubTopic:
Instruments
I'm working on a custom instrument that displays intervals from os_signpost data. I'd like to color the intervals in the graph based on data from an accompanying aggregate. For example, color the interval red if its duration is greater than 3 standard deviations from the mean. Is this possible?
Topic:
Developer Tools & Services
SubTopic:
Instruments
Hello, I am trying to investigate my apps memory usage using the instruments tool. Whenever I attach instruments my app crashes, when I have it connected to xcode as well I can see that the crash occurs in liboainject: ___lldb_unamed_symbol117 with SIGBUS.
Here's what the stack looks like.
Is this a known issue? Are there any workarounds or things I can do to figure out what is causing the crash?
Topic:
Developer Tools & Services
SubTopic:
Instruments
Hello,
I'm no macOS 26.1 I'm running through the example shown in the WWDC video "Optimizing CPU Performance with Instruments." After right-clicking a test, clicking "Profile...", and trying to run a processor trace I get the error in the subject.
I have processor trace enabled on the CPU via system settings. I confirmed this by disabling it and re-enabling it and noting the error that appears when this is disabled is different from the one I'm now getting.
This did previously work but I haven't tried since macOS 26 is released. Is there something new I need to be doing to my Xcode project settings in order for this to be working?
Topic:
Developer Tools & Services
SubTopic:
Instruments
This is a screenshot from the Swift Task track in Xcode.
I made these tasks with
public actor ResourceManager {
func foo() {
for observer in observers {
Task(name: "ResourceManager notify observers") {
await notification(observer)
}
}
}
}
I am confused why each of the task is showing as a separate task in the task lifetime summary. Is there a way to queue the trace in Instruments into the fact that these are indeed the same task?
I have been working on battery consumption analysis for my application, and as part of this effort, I wanted to understand how competitor apps behave under similar usage conditions.
To do this, I downloaded competitor apps from the App Store and attached them to Instruments via Xcode. I then executed a defined set of manual test scenarios to simulate real user behavior. During these tests, the iPhone was connected to a Mac and charging continuously, which meant that System Power Usage logs were not generated in Instruments.
However, I was able to capture detailed metrics such as:
Network usage
CPU load
GPU activity
Display and brightness impact
Other runtime performance characteristics
Since direct battery drain data was unavailable, I used derived analysis (with AI assistance) to estimate approximate power consumption based on the above metrics, assuming real-device (battery-powered) conditions.
According to Apple documentation, System Power Usage in Instruments is not directly tied to the device’s battery percentage. Instead, it appears to be computed using contributing factors such as CPU, network, display, and other subsystem activity. This raises a few important questions about data reliability and methodology.
Key questions:
How reliable are Instruments-based metrics (CPU, network, display, GPU) for estimating real-world battery consumption when the device is charging?
Can these metrics be safely used as a comparative baseline between competitor applications, even if absolute battery drain values are unavailable?
Is the System Power Usage instrument essentially a derived model based on subsystem activity, and if so, does it remain accurate when the device is not discharging?
From Apple’s perspective, is this a valid approach for relative power comparison, provided that:
The same device is used
OS version is identical
Test scenarios are consistent and repeatable
Based on these findings, would it be reasonable to proceed with instrumenting our own application, run the same scenarios, and draw conclusions using relative comparisons rather than absolute battery percentages?
The intent is not to claim exact battery drain numbers, but to establish a directionally correct and repeatable comparison that can guide performance optimizations in our own application.
I would like to understand whether this methodology aligns with Apple’s recommended practices, or if there are limitations or inaccuracies I should be aware of before relying on these results for decision-making.
Topic:
Developer Tools & Services
SubTopic:
Instruments
I am profiling a simple SwiftUI test app on my new iPhone through my new MacBook Pro and everything is version 26.2 (iOS, macOS, Xcode). I run Instruments with the SwiftUI template using all of the default settings and get absolutely zero data after interacting with the app for about 20 seconds. Using the Time Profiler template yields trace data. Trying the SwiftUI template again with the sample Landmarks app has the same issue as my app.
what is the diff between INST_ALL and Instructions(FIXED_INSTRUCTIONS)?
also CORE_ACTIVE_CYCLE VS Cycles(FIXED_CYCLES)
I am a developer creating an app for iOS 16 and my app mysteriously started showing a blank screen during previews and the simulator. I profiled the app launch with Instruments, and the results said that dlopen was running on the main thread for the whole minutes of profiling:
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)
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?
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!
Topic:
Developer Tools & Services
SubTopic:
Instruments