前言
本文的demo程式碼也會更新到github上。
做這個demo思路來源於微信team的：微信iOS卡頓監控系統。
主要思路:通過監測Runloop的kCFRunLoopAfterWaiting，用一個子執行緒去檢查，一次迴圈是否時間太長。
其中主要涉及到了runloop的原理。關於整個原理：深入理解RunLoop講解的比較仔細。
以下就是runloop大概的執行方式：
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/// 1. 通知Observers，即將進入RunLoop /// 此處有Observer會建立AutoreleasePool: _objc_autoreleasePoolPush(); __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopEntry); do { /// 2. 通知 Observers: 即將觸發 Timer 回撥。 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopBeforeTimers); /// 3. 通知 Observers: 即將觸發 Source (非基於port的,Source0) 回撥。 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopBeforeSources); __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__(block); /// 4. 觸發 Source0 (非基於port的) 回撥。 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__(source0); /// 5. GCD處理main block __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__(block); /// 6. 通知Observers，即將進入休眠 /// 此處有Observer釋放並新建AutoreleasePool: _objc_autoreleasePoolPop(); _objc_autoreleasePoolPush(); __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopBeforeWaiting); /// 7. sleep to wait msg. mach_msg() -> mach_msg_trap(); /// 8. 通知Observers，執行緒被喚醒 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopAfterWaiting); /// 9. 如果是被Timer喚醒的，回撥Timer __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__(timer); /// 9. 如果是被dispatch喚醒的，執行所有呼叫 dispatch_async 等方法放入main queue 的 block __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__(dispatched_block); /// 9. 如果如果Runloop是被 Source1 (基於port的) 的事件喚醒了，處理這個事件 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__(source1); } while (...); /// 10. 通知Observers，即將退出RunLoop /// 此處有Observer釋放AutoreleasePool: _objc_autoreleasePoolPop(); __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__(kCFRunLoopExit); } |
其中UI主要集中在__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__(source0);
和__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__(source1);之前。
獲取kCFRunLoopBeforeSources到kCFRunLoopBeforeWaiting再到kCFRunLoopAfterWaiting的狀態就可以知道是否有卡頓的情況。
NSTimer的實現
具體程式碼如下：
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// // MonitorController.h // RunloopMonitorDemo // // Created by game3108 on 16/4/13. // Copyright © 2016年 game3108. All rights reserved. // #import @interface MonitorController : NSObject + (instancetype) sharedInstance; - (void) startMonitor; - (void) endMonitor; - (void) printLogTrace; @end |
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// // MonitorController.m // RunloopMonitorDemo // // Created by game3108 on 16/4/13. // Copyright © 2016年 game3108. All rights reserved. // #import "MonitorController.h" #include #include @interface MonitorController(){ CFRunLoopObserverRef _observer; double _lastRecordTime; NSMutableArray *_backtrace; } @end @implementation MonitorController static double _waitStartTime; + (instancetype) sharedInstance{ static dispatch_once_t once; static id sharedInstance; dispatch_once(&once, ^{ sharedInstance = [[self alloc] init]; }); return sharedInstance; } - (void) startMonitor{ [self addMainThreadObserver]; [self addSecondaryThreadAndObserver]; } - (void) endMonitor{ if (!_observer) { return; } CFRunLoopRemoveObserver(CFRunLoopGetMain(), _observer, kCFRunLoopCommonModes); CFRelease(_observer); _observer = NULL; } #pragma mark printLogTrace - (void)printLogTrace{ NSLog(@"====================堆疊\n %@ \n",_backtrace); } #pragma mark addMainThreadObserver - (void) addMainThreadObserver { dispatch_async(dispatch_get_main_queue(), ^{ //建立自動釋放池 @autoreleasepool { //獲得當前thread的Run loop NSRunLoop *myRunLoop = [NSRunLoop currentRunLoop]; //設定Run loop observer的執行環境 CFRunLoopObserverContext context = {0, (__bridge void *)(self), NULL, NULL, NULL}; //建立Run loop observer物件 //第一個引數用於分配observer物件的記憶體 //第二個引數用以設定observer所要關注的事件，詳見回撥函式myRunLoopObserver中註釋 //第三個引數用於標識該observer是在第一次進入run loop時執行還是每次進入run loop處理時均執行 //第四個引數用於設定該observer的優先順序 //第五個引數用於設定該observer的回撥函式 //第六個引數用於設定該observer的執行環境 _observer = CFRunLoopObserverCreate(kCFAllocatorDefault, kCFRunLoopAllActivities, YES, 0, &myRunLoopObserver, &context); if (_observer) { //將Cocoa的NSRunLoop型別轉換成Core Foundation的CFRunLoopRef型別 CFRunLoopRef cfRunLoop = [myRunLoop getCFRunLoop]; //將新建的observer加入到當前thread的run loop CFRunLoopAddObserver(cfRunLoop, _observer, kCFRunLoopDefaultMode); } } }); } void myRunLoopObserver(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info) { switch (activity) { //The entrance of the run loop, before entering the event processing loop. //This activity occurs once for each call to CFRunLoopRun and CFRunLoopRunInMode case kCFRunLoopEntry: NSLog(@"run loop entry"); break; //Inside the event processing loop before any timers are processed case kCFRunLoopBeforeTimers: NSLog(@"run loop before timers"); break; //Inside the event processing loop before any sources are processed case kCFRunLoopBeforeSources: NSLog(@"run loop before sources"); break; //Inside the event processing loop before the run loop sleeps, waiting for a source or timer to fire. //This activity does not occur if CFRunLoopRunInMode is called with a timeout of 0 seconds. //It also does not occur in a particular iteration of the event processing loop if a version 0 source fires case kCFRunLoopBeforeWaiting:{ _waitStartTime = 0; NSLog(@"run loop before waiting"); break; } //Inside the event processing loop after the run loop wakes up, but before processing the event that woke it up. //This activity occurs only if the run loop did in fact go to sleep during the current loop case kCFRunLoopAfterWaiting:{ _waitStartTime = [[NSDate date] timeIntervalSince1970]; NSLog(@"run loop after waiting"); break; } //The exit of the run loop, after exiting the event processing loop. //This activity occurs once for each call to CFRunLoopRun and CFRunLoopRunInMode case kCFRunLoopExit: NSLog(@"run loop exit"); break; /* A combination of all the preceding stages case kCFRunLoopAllActivities: break; */ default: break; } } #pragma mark addSecondaryThreadAndObserver - (void) addSecondaryThreadAndObserver{ NSThread *thread = [self secondaryThread]; [self performSelector:@selector(addSecondaryTimer) onThread:thread withObject:nil waitUntilDone:YES]; } - (NSThread *)secondaryThread { static NSThread *_secondaryThread = nil; static dispatch_once_t oncePredicate; dispatch_once(&oncePredicate, ^{ _secondaryThread = [[NSThread alloc] initWithTarget:self selector:@selector(networkRequestThreadEntryPoint:) object:nil]; [_secondaryThread start]; }); return _secondaryThread; } - (void)networkRequestThreadEntryPoint:(id)__unused object { @autoreleasepool { [[NSThread currentThread] setName:@"monitorControllerThread"]; NSRunLoop *runLoop = [NSRunLoop currentRunLoop]; [runLoop addPort:[NSMachPort port] forMode:NSRunLoopCommonModes]; [runLoop run]; } } - (void) addSecondaryTimer{ NSTimer *myTimer = [NSTimer timerWithTimeInterval:0.5 target:self selector:@selector(timerFired:) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop] addTimer:myTimer forMode:NSDefaultRunLoopMode]; } - (void)timerFired:(NSTimer *)timer{ if ( _waitStartTime 2.0){ if (_lastRecordTime - _waitStartTime |
主要內容是首先在主執行緒註冊了runloop observer的回撥myRunLoopObserver
每次小迴圈都會記錄一下kCFRunLoopAfterWaiting的時間_waitStartTime，並且在kCFRunLoopBeforeWaiting制空。
另外開了一個子執行緒並開啟他的runloop（模仿了AFNetworking的方式），並加上一個timer每隔1秒去進行監測。
如果當前時長與_waitStartTime差距大於2秒，則認為有卡頓情況，並記錄了當前堆疊資訊。
PS:整個demo寫的比較簡單，最後獲取堆疊也僅獲取了當前執行緒的堆疊資訊([NSThread callStackSymbols]有同樣效果)，也在尋找獲取所有執行緒堆疊的方法，歡迎指點一下。
更新：
瞭解到 plcrashreporter (github地址) 可以做到獲取所有執行緒堆疊。
更新2:
這篇文章也介紹了監測卡頓的方法：檢測iOS的APP效能的一些方法
通過Dispatch Semaphore保證同步這裡記錄一下。
寫一個Semaphore版本的程式碼，也放在github上：
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// // SeMonitorController.h // RunloopMonitorDemo // // Created by game3108 on 16/4/14. // Copyright © 2016年 game3108. All rights reserved. // #import @interface SeMonitorController : NSObject + (instancetype) sharedInstance; - (void) startMonitor; - (void) endMonitor; - (void) printLogTrace; @end |
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// // SeMonitorController.m // RunloopMonitorDemo // // Created by game3108 on 16/4/14. // Copyright © 2016年 game3108. All rights reserved. // #import "SeMonitorController.h" #import #import @interface SeMonitorController(){ CFRunLoopObserverRef _observer; dispatch_semaphore_t _semaphore; CFRunLoopActivity _activity; NSInteger _countTime; NSMutableArray *_backtrace; } @end @implementation SeMonitorController + (instancetype) sharedInstance{ static dispatch_once_t once; static id sharedInstance; dispatch_once(&once, ^{ sharedInstance = [[self alloc] init]; }); return sharedInstance; } - (void) startMonitor{ [self registerObserver]; } - (void) endMonitor{ if (!_observer) { return; } CFRunLoopRemoveObserver(CFRunLoopGetMain(), _observer, kCFRunLoopCommonModes); CFRelease(_observer); _observer = NULL; } - (void) printLogTrace{ NSLog(@"====================堆疊\n %@ \n",_backtrace); } static void runLoopObserverCallBack(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info) { SeMonitorController *instrance = [SeMonitorController sharedInstance]; instrance->_activity = activity; // 傳送訊號 dispatch_semaphore_t semaphore = instrance->_semaphore; dispatch_semaphore_signal(semaphore); } - (void)registerObserver { CFRunLoopObserverContext context = {0,(__bridge void*)self,NULL,NULL}; _observer = CFRunLoopObserverCreate(kCFAllocatorDefault, kCFRunLoopAllActivities, YES, 0, &runLoopObserverCallBack, &context); CFRunLoopAddObserver(CFRunLoopGetMain(), _observer, kCFRunLoopCommonModes); // 建立訊號 _semaphore = dispatch_semaphore_create(0); // 在子執行緒監控時長 dispatch_async(dispatch_get_global_queue(0, 0), ^{ while (YES) { // 假定連續5次超時50ms認為卡頓(當然也包含了單次超時250ms) long st = dispatch_semaphore_wait(_semaphore, dispatch_time(DISPATCH_TIME_NOW, 50*NSEC_PER_MSEC)); if (st != 0) { if (_activity==kCFRunLoopBeforeSources || _activity==kCFRunLoopAfterWaiting) { if (++_countTime |
用Dispatch Semaphore簡化了程式碼複雜度，更加簡潔。
參考資料
1.微信iOS卡頓監控系統
2. iphone——使用run loop物件
3.深入理解RunLoop
4.檢測iOS的APP效能的一些方法
5.iOS實時卡頓監控