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“offloading”

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Reply to iPhone and iPad accelerometer specifications

Hi all, I'm looking for the specifications for the accelerometers used in current iPhone and iPad devices, including the sensitivity and the update rates possible. We've never published any formal documentation about what the exact capabilities of the hardware were. However, I have a word of caution around this: Despite the documentation saying it's 100Hz, I've not yet found it to be better than 50Hz on any of iPhone SE, 8 or 11, nor iPad mini or Pros. Having worked with many developers using CoreMotion, I've seen the same pattern happen MANY times: A basic motion analysis engine is implemented, typically using the real time API and the with a target queue. The main thread or other busy thread are entangled with that algorithm, either because the code is running directly on that thread or because of implicit relationships which aren't as visible. Testing begins and the results are somewhat positive, however, there are issues with random data glitches or other oddities in the data. The assumption is made that

App & System Services Core OS

Sep ’24

Reply to RunLoop behaviour change with performBlock?

Can you clarify the circumstances in which mach ports are leaked? Well, the unhelpful (and slightly flippant) answer is basically anytime they're not properly deallocated when they're no longer useful. More practically, the whole reason mach ports create issues IS that it's often quite difficult to connect any given mach port with the specific component responsible for managing that unit. In terms of run loop semantics specifically, I think you'd (potentially) generate a leak anytime you destroy an thread without removing/stopping all of it's input sources*. *Strictly speaking, that isn't necessarily a guaranteed leak. For example, some of our frameworks register thread destruction handlers so to handle clean up. However, at that point you're relying on the details of our own implementation, which is never ideal. Also, keep in mind that this isn't just about mach port leakage, but could involve any other resource who's management happened to be tied to that thread. The while loop in the original post is in a

App & System Services General

Nov ’24

Metal Matrix Multiplication reference code

Hi,I have just started experimenting with Metal. I really just want to offload a few matrix multiplications to the GPU.So, I downloaded this perfectly applicable example code and ran it: https://developer.apple.com/library/ios/samplecode/MetalPartialSumsCompute/Introduction/Intro.html#//apple_ref/doc/uid/TP40015013-Intro-DontLinkElementID_2I can run it on my iphone 6 but there are several issues:It crashes sometimes (EXC_BAD_ACCESS (code=1), and other malloc errors). That's a bit worrying for reference code.It says I am getting approximately 0.04 gflops/sec[sic] using either CPU (Accelerate) or GPU (Metal). I believe I should be getting 3+ GFLOPS from the CPU? (http://www.anandtech.com/show/8554/the-iphone-6-review/3) I'm not sure what to expect from the GPU/Metal but I am assuming a considerably higher number.Here's example output:2015-12-02 14:48:27.772 MetalMatrixMultiply[5477:2056717] >> [12] Matrix Dimensions: A = [1248 x 1137], B = [1137 x 2004], C = [1248 x 2004], lda = 1248, ldb = 2008,

Graphics & Games General Metal

2.2k

Dec ’15

EndpointSecurity: es_new_client freezes all operations until other clients decide pending messages?

I have 2 EndpointSecurity apps. App1 is doing the heavy lifting and processes multiple events(ES_EVENT_TYPE_AUTH_EXEC, ES_EVENT_TYPE_AUTH_OPEN, ES_EVENT_TYPE_AUTH_RENAME, ES_EVENT_TYPE_AUTH_UNLINK, ES_EVENT_TYPE_NOTIFY_CLOSE, ES_EVENT_TYPE_NOTIFY_CREATE ). App2 is responsible for checking whether Full Disk Access is granted or not: int main(int argc, char * argv[]) { ttes_client_t *client; auto res = es_new_client(&client, ^(es_client_t *clt, const es_message_t *msg) { }); tt_exit(res == ES_NEW_CLIENT_RESULT_ERR_NOT_PERMITTED ? 0 : 1); } (please note that none of the apps is a System Extension). Sometimes when App1 is runing and App2 executes, the system hangs. After few days of investigation, it seems that starting a new es client (even without registering any messages) causes the system to block all operations until all the currently pending auth requests from other clients are answered. This makes it very hard to reason about the application. It also requires to basically offload everything to

Privacy & Security General Endpoint Security

466

Jul ’20

Strange Microphone Issue on iOS 17.0.3

Hi all, I'm facing a strange issue on my iPhone 15 Pro Max with iOS 17.0.3 official release. A few days ago I was using WeChat and was making a voice call with my Airpods, and accidentally dropeed one of the Airdpod, after I picked it up, all of a sudden the person on the other end cannot hear me via the voice call anymore. Then I tried to send a voice message on WeChat and noticed it's also failing. Here's a list of things I've tried to investigate/narrow down this issue: I checked in Privacy settings and confirmed the toggle for Microphone is turned on for WeChat, also tried switching it to off then back on. I also checked WeChat's own permission settings and made sure all the toggles for Microphone are turned on, also tried switching them to off then back on. Tested other apps that uses the microphone (e.g. phone, facetime, voice memo, instagram, QQ (also from Tencent) etc.), and they are all working fine. Tried normal restart and hard restart of the phone, issue persists Log out from Wechat and log back i

App & System Services Core OS iOS

3.0k

Oct ’23

Querying data from one-to-many relationship by aggregate in swiftdata

Hi all, I've been struggling a bit with SwiftData, I have a really simple data model but I need to do a fairly complex query over a one-to-many relationship that results in aggregate values. And I want to be able to sort and filter those aggregates. The model looks like this: @Model class Category { var name: String var items = [Item]() } @Model class Item { var added: Date var checked: Date? } In a typical use case I'd expect their to be at most around 50 categories and perhaps 20 items per category. In my UI I would like to be able to sort categories in a couple of ways: by name, by date added and by date checked with a fallback on date added. Also, in my list view I want to be able to list categories and show the checked date of the most recently checked item. I can think of a couple of solutions here, to start of with I can do all the sorting and filtering client-side. In the list view I could retrieve all the categories and then find the most recently checked item per category and go from there. Another

App & System Services iCloud & Data SwiftData

507

Jan ’24

TTS Alex voice is treated like available when it's actually not

Hello everybody! In my app I allow the user to change TTS voices and English Alex voice is one of possible options. However, there are some cases when it's treated as available when it's actually not. It results in pronouncing the TTS utterance with another voice. To prepare the list of available voices I use next code: NSMutableArray *voices = [NSMutableArray new]; for (AVSpeechSynthesisVoice *voice in [AVSpeechSynthesisVoice speechVoices]) { tt[voices addObject:@{ tttt@id: voice.identifier, tttt@name: voice.name, tttt@language: voice.language, tttt@quality: (voice.quality == AVSpeechSynthesisVoiceQualityEnhanced) ? @500 : @300 tt}]; } To start the playback I use the next code (here it's simplified a bit): AVSpeechUtterance *utterance = [[AVSpeechUtterance alloc] initWithString:text]; utterance.voice = [AVSpeechSynthesisVoice voiceWithIdentifier:voice]; [AVSpeechSynthesizer speakUtterance:utterance]; Cases when AVSpeechSynthesisVoice returns Alex as available when it's not: The easiest way to reproduce it is

Machine Learning & AI General Speech iOS AVFoundation

2.7k

Oct ’20

watchOS 11.2 Debug Tunnel Timeout: iPhone Connected, Watch stuck in "Waiting to Reconnect" (Xcode 16.4)

Hello, I am experiencing a critical blocking issue developing a watchOS app. While the iPhone 15 Pro Max is fully Connected via USB (confirmed green light in Network Settings), the Apple Watch Series 7 (watchOS 11.2) remains unreachable by Xcode. Mac: Mac Mini (macOS 15/16). Devices: iPhone 15 Pro Max (iOS 18+), Apple Watch Series 7 (watchOS 11.2). Xcode: 16.4 / Build 26.4. Hardware: Direct USB-C connection (USB 2.0 480Mb/s protocol). Technical Evidence of Protocol Failure: Missing Staging Folders: ~/Library/Developer/Xcode/watchOS DeviceSupport does not exist, implying the handshake fails before symbol stripping/sync begins. CoreDevice Error: Consistently receiving: Previous preparation error: A connection to this device could not be established.; Timed out while attempting to establish tunnel using negotiated network parameters. Missing Keychain Entries: No com.apple.coredevice keys found in Keychain Access, suggesting the Trusted Host handshake is incomplete. mDNS/Discovery: xcrun devicectl list devices sh

Developer Tools & Services Xcode

VPN (Packet Tunnel Provider) over SMB

Some users at a certain company reported they are having problems when using my VPN app for Mac (Packet Tunnel Povider), with SMB:Initiating an SMB upload will fail and then their VPN client will disconnect, in some cases the computer needs to be reboot.I've collected logs for my client (nothing suspicious there), and I also got the logs from thier Console.Those are some relevant lines from the Console, but again I don't see anything suspicious:default 17:27:16.194234 -0400 secd Microsoft Outloo[303]/1#16 LF=0 copy_matching Error Domain=NSOSStatusErrorDomain Code=-34018 Client has neither com.apple.application-identifier, com.apple.security.application-groups nor keychain-access-groups entitlements UserInfo={NSDescription=Client has neither com.apple.application-identifier, com.apple.security.application-groups nor keychain-access-groups entitlements} default 17:27:16.252627 -0400 com.apple.WebKit.WebContent Current memory footprint: 14 MB default 17:27:18.079823 -0400 symptomsd rssi (-53) or transmitRate (58

App & System Services Networking Network

1.5k

Mar ’20

Discover and connect to BLE peripherals more rapidly in background

We are developing an app which connects to a BLE peripheral in the background whenever it gets close to it. What we have used so far is that we monitor a circular region. When the phone enters the region the app will start scanning for peripherals and when it discovers the peripheral it connects to it. This worked pretty well for the last few iOS versions, perhaps iOS 14-16. It wasn't perfect but for the most part it would feel like it connected rather quickly when you would approach the BLE peripheral. If you listen to music via BLE or talk to someone using your BLE headset then it could sometimes work noticeably worse. But, as said, for the most part it would work satisfactory. Starting with iOS 17 and analyzing the functionality over the past 6 months or so we've noticed a clear worsening of it. It does generally connect to the peripheral but the user might often have to wait for quite some time. Rather frequently the user must even light up the screen of the phone before anything even happens. It appears

App & System Services Core OS Background Tasks Core Bluetooth

1.2k

May ’24

Questions for Security lab (Tuesday, June 4th at 11:00 AM)

Auditing:Question: What will change/improve in proper way to offload audit information (log to SIEM systems) comparable to Apple > GitHub > swift-log idea, but build into OS auditing systems?Answer:File a Radar to request streaming of OpenBSM logs to syslog.File another Radar to request macOS Catalina be upgraded with the latest version of OpenBSM, which supports exporting to plain text natively.FileVault:Question: In the WWDC Catalina beta, enabling FileVault with fdesetup includes a dialog window for user approval (see below). Is there a way to suppress this window from appearing?Answer: Dialog window was added as ransomware protection. File a Radar to request an MDM option for suppressing dialog window.Endpoint Security:Question: Will the new EndpointSecurity framework be available for iOS/iPadOS?Answer: No.Kernel Extensions:Question: Any timeline on when they will be fully deprecated?Answer: Apple does not comment on future product releases.Question: Beyond disabling SIP, are there other wa

App & System Services Core OS Beta macOS

3.0k

Jun ’19

Passpoint Network Performance Different using API vs .mobileconfig

Hi All, We are developing a hybrid MVNO and want to use Wi-Fi Passpoint to enable offload from our users phones when they are in range of our Wi-Fi network. The user experience of installing a .mobileconfig file is too many steps and a bad user experience which causes low adoption among our users. Instead, we want to use the NEHotspotConfigurationManager to configure a HS2.0 network using EAP-TLS. We configure these elements using NEHotspotConfiguration NEHotspotHS20Settings NEHotspotEAPSettings Our code to execute above is shown below: func configureProfile(certificate: String, issuingCa: String, caChain: [String], resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) { #if !targetEnvironment(simulator) let keychainQuery = [kSecClass as String: kSecClassCertificate] as [String: Any] as CFDictionary let status = SecItemDelete(keychainQuery) print(Delete status (status)) let url = Bundle.main.url(forResource: serverCA, withExtension: crt)! let caCert = try! String(content

App & System Services Networking

557

Aug ’24

TaskGroup lockup with more than 7 tasks

Platform: macOS 12.4, MacBook Pro 2.3GHz Quad-Core i5, 16GB RAM I'm trying to read an OSLog concurrently because it is big and I don't need any of the data in order. Because the return from .getEntries is a sequence, the most efficient approach seems to be to iterate through. Iteration through the sequence from start to finish can take a long time so I thought I can split it up into days and concurrently process each day. I'm using a task group to do this and it works as long as the number of tasks is less than 8. When it works, I do get the result faster but not a lot faster. I guess there is a lot of overhead but actually it seems to be that my log file is dominated by the processing on 1 of the days. Ideally I want more concurrent tasks to break up the day into smaller blocks. But as soon as I try to create 8 or more tasks, I get a lockup with the following error posted to the console. enable_updates_common timed out waiting for updates to reenable Here are my tests. First - a pure iterative approach. No t

App & System Services Processes & Concurrency Concurrency OSLog wwdc2022-10142

2.7k

Jun ’22

MTKView Drawing Performance

What I am Trying to DoI am trying to show filters on a camera feed by using a Metal view: MTKView. I am closely following the method of Apple's sample code - Enhancing Live Video by Leveraging TrueDepth Camera Data - linkWhat I Have So FarFollowing code works great (mainly interpreted from above-mentioned sample code) :class MetalObject: NSObject, MTKViewDelegate { private var metalBufferView : MTKView? private var metalDevice = MTLCreateSystemDefaultDevice() private var metalCommandQueue : MTLCommandQueue! private var ciContext : CIContext! private let colorSpace = CGColorSpaceCreateDeviceRGB() private var videoPixelBuffer : CVPixelBuffer? private let syncQueue = DispatchQueue(label: Preview View Sync Queue, qos: .userInitiated, attributes: [], autoreleaseFrequency: .workItem) private var textureWidth : Int = 0 private var textureHeight : Int = 0 private var textureMirroring = false private var sampler : MTLSamplerState! private var renderPipelineState : MTLRenderPipelineState! private var vertexCoordBuffer

Media Technologies Audio AVFoundation

2.9k

Apr ’19

Need Resources: Kernel and SpoghtlightNetHelper Unauthorized System Access

To Whom It May Concern:I apparently have a self propagating virus that was introduced to my network by purchase of a used Mac computer from Amazon.com on approximately December 24, 2015. That is when I first started noticing erratic behavior on my machines. I have clean formatted and reinstalled OS from computers on an isolated network that was not infected. As soon as I connect the newly reinstalled OS iMacs to the infected network they become reinfected on first boot. I've spent something like 40 labor hours on this so far and I can't afford anymore resource allocation to this issue until there are some steps to cure the system.This activity on my computer appears to be a nasty virus. From what I can tell, it tries injecting itself in every executable it can locate. It trys to obtain the icloud login credentials, it attempts to obtain administrator credentials, and on one computer it appears to have secured and stolen my credentials to completely hijack the computer. Once it hijacks the computer it deletes

Privacy & Security General Security

2.3k

Jan ’16

Reply to iPhone and iPad accelerometer specifications

App & System Services Core OS