This is done once (OS X 10.10.5):
commonSendQueue = dispatch_queue_create( “common socket queue",
DISPATCH_QUEUE_SERIAL);
Several objects do this quite often:
NSDate *dax0 = [ NSDate date ];
dispatch_async(commonSendQueue, ^{ @autoreleasepool { [ someOtherObject
doSomethingwithDate: dax0]; }});
double delay1 = 50 msec
NSDate *dax1 = [ NSDate dateWithTimeInterval: delay1 sinceDate: dax0 ];
dispatch_time_t disTim1 = dispatch_time(DISPATCH_TIME_NOW, (int64_t)( delay1 *
NSEC_PER_SEC));
dispatch_after(disTim1, commonSendQueue, ^{ @autoreleasepool { [
someOtherObject doSomethingwithDate: dax1]; }});
someOtherObject does:
- (void) doSomethingwithDate: (NSDate *)date
{
NSTimeInterval inDelay = -date.timeIntervalSinceNow * 1e3;
if ( inDelay > 12 ) NSLog(@"%s in-delay %9.3f msec",__FUNCTION__,
inDelay);
}
The in-delay is usually less than a dozen milliseconds.
But in the call with dispatch_after (never with dispatch_async) the in-daly is
sometimes is 10 seconds - sometimes even 20 or 30 seconds - mostly (but not
always) near an integral multiple of 10 seconds.
Why this delay of 10 seconds, and how can I find out, what is the cause of it?
A breakpoint in doSomethingwithDate shows:
* thread #12: tid = 0x341eb, 0x0000000100012a43 gLifx`-[GCDAsyncUdpSocket
doSomethingwithDate:](self=0x00006180001e7300, _cmd=“ doSomethingwithDate:",
date=2016-03-30 06:34:00 UTC) + 179 at GCDAsyncUdpSocket.m:1851, queue =
'common socket queue', stop reason = breakpoint 1.1
—
* frame #0: 0x0000000100012a43 gLifx`-[GCDAsyncUdpSocket
doSomethingwithDate:](self=0x00006180001e7300, _cmd="doSomethingwithDate:",
date=2016-03-30 06:34:00 UTC) + 179 at GCDAsyncUdpSocket.m:1851
frame #1: 0x00000001000830ea gLifx`__52-[LFXUDPGatewayConnection
sendNextMessageFromOutbox]_block_invoke186(.block_descriptor=0x00006000000852d0)
+ 138 at LFXUDPGatewayConnection.m:359
frame #2: 0x000000010018c989
libdispatch.dylib`_dispatch_call_block_and_release + 12
frame #3: 0x0000000100187fc3 libdispatch.dylib`_dispatch_client_callout + 8
frame #4: 0x000000010019cd40
libdispatch.dylib`_dispatch_after_timer_callback + 322
frame #5: 0x0000000100187fc3 libdispatch.dylib`_dispatch_client_callout + 8
frame #6: 0x0000000100196b20
libdispatch.dylib`_dispatch_source_latch_and_call + 1239
frame #7: 0x000000010018df1c libdispatch.dylib`_dispatch_source_invoke + 425
frame #8: 0x000000010018c471 libdispatch.dylib`_dispatch_queue_drain + 1002
frame #9: 0x000000010018bf28 libdispatch.dylib`_dispatch_queue_invoke + 223
frame #10: 0x000000010018b9de libdispatch.dylib`_dispatch_root_queue_drain
+ 666
frame #11: 0x000000010018b73c libdispatch.dylib`_dispatch_worker_thread3 +
106
frame #12: 0x00007fff91241a9d libsystem_pthread.dylib`_pthread_wqthread +
729
frame #13: 0x00007fff9123f3dd libsystem_pthread.dylib`start_wqthread + 13
(lldb)
Gerriet.
P.S. instead of dispatch_after I tried NSTimer and nanosleep. Same problem.
I also removed the autorelasepool - made no difference.
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