proliferating CFURLCache worker threads
proliferating CFURLCache worker threads
- Subject: proliferating CFURLCache worker threads
- From: Martin Wierschin <email@hidden>
- Date: Mon, 21 May 2012 20:34:42 -0700
| Hello everyone,
Does anyone know anything about "com.apple.CFURLCACHE_work_queue" and how many of these queues/threads should be running at once? Normally I wouldn't care about such a detail, but I have several collected crash reports where these threads are proliferating (sometimes into the hundreds).
All these threads look like this: Thread 89:: Dispatch queue: com.apple.CFURLCACHE_work_queue 0 libsystem_kernel.dylib 0x93609c5e semaphore_wait_trap + 10
1 libdispatch.dylib 0x975c34e4 _dispatch_thread_semaphore_wait + 25
2 libdispatch.dylib 0x975c2628 _dispatch_barrier_sync_f_slow + 121
3 libdispatch.dylib 0x975c273c dispatch_barrier_sync_f + 37
4 libdispatch.dylib 0x975c28c4 dispatch_sync + 45
5 com.apple.CFNetwork 0x9b0f73de _ZL21_CFURLCacheDeallocatePKv + 234
6 com.apple.CoreFoundation 0x9508e1d1 CFRelease + 577
7 com.apple.CFNetwork 0x9b059ee1 ProcessCacheTasks(__CFURLCache*, bool) + 321
8 com.apple.CFNetwork 0x9b059715 _ZL24_CFURLCacheTimerCallbackPv + 721
9 libdispatch.dylib 0x975bffc9 _dispatch_call_block_and_release + 15
10 libdispatch.dylib 0x975c194f _dispatch_queue_drain + 224
11 libdispatch.dylib 0x975c17f4 _dispatch_queue_invoke + 47
12 libdispatch.dylib 0x975c0ffc _dispatch_worker_thread2 + 187
13 libsystem_c.dylib 0x98b31b24 _pthread_wqthread + 346
14 libsystem_c.dylib 0x98b336fe start_wqthread + 30
None of these threads are directly crashed. The crash is always some other thread, which I think occurs because the process is running out of file descriptors. An example I've seen more than once:
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 ??? 0000000000 0 + 0
1 com.apple.opencl 0x017501fe PlatformLoadDevice + 1722
2 com.apple.opencl 0x0174f553 PlatformInitCLCPU + 66
3 libsystem_c.dylib 0x98b2f487 pthread_once + 76
4 com.apple.opencl 0x0174f4b1 PlatformInitCL + 61
5 com.apple.opencl 0x0174f787 clGetDeviceIDs + 223
6 com.apple.opencl 0x01750f20 clCreateContextFromType + 65
7 com.apple.CoreImage 0x9a379136 ___createCPUclContext_block_invoke_0 + 67
8 libdispatch.dylib 0x975c3c27 dispatch_once_f + 50
9 libdispatch.dylib 0x975c3bf0 dispatch_once + 31
10 com.apple.CoreImage 0x9a375ce4 -[FEOpenCLContext initWithOptions:] + 710
...
45 com.apple.HIToolbox 0x97ab116b HIView::Draw(short, OpaqueGrafPtr*, unsigned long) + 81
46 com.apple.HIToolbox 0x97ab1533 HIView::Render(unsigned long, CGContext*) + 45
47 com.apple.HIToolbox 0x97a46ebb WindowData::PrepareForVisibility() + 137
48 com.apple.HIToolbox 0x97cd0fb7 _HIWindowPrepareForVisibility + 29
49 com.apple.HIToolbox 0x97bde7c5 _ZL8DrawMDEFP14MenuSelectData7CGPoint + 698
50 com.apple.HIToolbox 0x97bded50 _ZL11DrawTheMenuP14MenuSelectDataPP9__CFArrayhPh + 622
51 com.apple.HIToolbox 0x97bdf11e _ZL11MenuChangedP14MenuSelectDatahh + 608
52 com.apple.HIToolbox 0x97a4d949 _ZL15TrackMenuCommonR14MenuSelectDataPh + 1235
53 com.apple.HIToolbox 0x97be29a4 _ZL14MenuSelectCoreP8MenuData5PointdmPP13OpaqueMenuRefPt + 420
54 com.apple.HIToolbox 0x97a49bde _HandleMenuSelection2 + 636
55 com.apple.HIToolbox 0x97a4995d _HandleMenuSelection + 53
56 com.apple.AppKit 0x001cedbc _NSHandleCarbonMenuEvent + 302
57 com.apple.AppKit 0x0015f6c6 _DPSNextEvent + 2196
58 com.apple.AppKit 0x0015e942 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 113
59 com.apple.AppKit 0x0015acb1 -[NSApplication run] + 911
60 com.apple.AppKit 0x003ebbd9 NSApplicationMain + 1054
61 com.company.MyApp 0x00005dc1 main + 30
62 com.company.MyApp 0x00001fc5 start + 53
I don't know what that CoreImage/opencl stuff does, but my suspicion is that my app is running out of a limited resource. Allocated RAM isn't very high, so my best guess is file descriptors, which is why I'm suspicious about all the CFURLCache threads.
Some additional information: I'm using WebKit (indirectly via NSAttributedString's HTML loading methods) to import many HTML files. Each HTML load is wrapped in an autorelease pool, and I've run leaks (and done heapshot analysis) without turning up any mismanaged resources on my part. So it seems perhaps my HTML import requests are outstripping WebKit/CFURLCache's ability to cleanup after itself.
Does anyone have any thoughts on this situation?
Thanks for any thoughts or advice, ~Martin
|
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