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[Xcode/iOS] 'Queue : RPAC issue generation queue (serial)' works with 100% CPU

During my application debug in Xcode, I noticed a queue named 'RPAC issue generation queue (serial)' that always takes 100% CPU. According to backtraces, it looks like it triggered for various resources my application uses: colors from the asset catalog, and strings from localized strings files. Overall, I try to keep my application optimized but having the system process taking 100% of the device CPU all the time levels out my efforts.


Any information regarding this queue and possible solutions is greatly appreciated.


Xcode 15.3 (15E204a)

iOS 17.4.1 (21E236)


Example backtrace:

```

Thread 4 Queue : RPAC issue generation queue (serial)

#0 0x00000001cac2282c in dyld3::MachOLoaded::findClosestSymbol(unsigned long long, char const**, unsigned long long*) const ()

#1 0x00000001cac22070 in dyld4::APIs::dladdr(void const*, dl_info*) ()

#2 0x00000001af601624 in backtrace_symbols ()

#3 0x0000000109440c2c in __generateCulledBacktrace_block_invoke_2 ()

#4 0x0000000109984b98 in _dispatch_call_block_and_release ()

#5 0x00000001099867bc in _dispatch_client_callout ()

#6 0x000000010998e66c in _dispatch_lane_serial_drain ()

#7 0x000000010998f408 in _dispatch_lane_invoke ()

#8 0x000000010999c404 in _dispatch_root_queue_drain_deferred_wlh ()

#9 0x000000010999ba38 in _dispatch_workloop_worker_thread ()

#10 0x000000020368cf20 in _pthread_wqthread ()

Enqueued from com.apple.main-thread (Thread 1) Queue : com.apple.main-thread (serial)

#0 0x000000010998b448 in dispatch_async ()

#1 0x0000000109440a90 in generateCulledBacktrace ()

#2 0x000000010943e204 in main_thread_general_check ()

#3 0x00000001093b9510 in trampoline_c ()

#4 0x00000001093ba844 in handler_start_1c ()

#5 0x00000001a99ef49c in +[_UIAssetManager assetManagerForBundle:] ()

#6 0x00000001a9b19394 in +[UIColor colorNamed:inBundle:compatibleWithTraitCollection:] ()

#7 0x0000000106192f38 in @nonobjc UIColor.__allocating_init(named:in:compatibleWith:) ()

...

```

iPhone 12 mini, iOS 17

Posted on Apr 16, 2024 8:07 AM

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[Xcode/iOS] 'Queue : RPAC issue generation queue (serial)' works with 100% CPU

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