ios利用RunLoop原理实现去监控卡顿实例详解
<div id="navCategory"><h5 class="catalogue">目录</h5><ul class="first_class_ul"><li>一、卡顿问题的几种原因</li><li>二、监测卡顿的思路</li><ul class="second_class_ul"><li>监测FPS：</li><li>RunLoop：</li></ul><li>三、如何检查卡顿</li><ul class="second_class_ul"></ul></ul></div><p class="maodian"></p><h2>一、卡顿问题的几种原因</h2><p>复杂 UI 、图文混排的绘制量过大；</p>
<p>在主线程上做网络同步请求；</p>
<p>在主线程做大量的 IO 操作；</p>
<p>运算量过大，CPU 持续高占用；</p>
<p>死锁和主子线程抢锁。</p>
<p class="maodian"></p><h2>二、监测卡顿的思路</h2>
<p class="maodian"></p><h3>监测FPS：</h3>
<p>FPS 是一秒显示的帧数，也就是一秒内画面变化数量。如果按照动画片来说，动画片的 FPS 就是 24，是达不到 60 满帧的。也就是说，对于动画片来说，24 帧时虽然没有 60 帧时流畅，但也已经是连贯的了，所以并不能说 24 帧时就算是卡住了。 由此可见，简单地通过监视 FPS 是很难确定是否会出现卡顿问题了，所以我就果断弃了通过监视 FPS 来监控卡顿的方案。</p>
<p class="maodian"></p><h3>RunLoop：</h3>
<p>通过监控 RunLoop 的状态来判断是否会出现卡顿。RunLoop原理这里就不再多说，主要说方法，首先明确loop的状态有六个</p>
<div class="jb51code"><pre class="brush:cpp;">typedef CF_OPTIONS(CFOptionFlags, CFRunLoopActivity) {
kCFRunLoopEntry , // 进入 loop
kCFRunLoopBeforeTimers , // 触发 Timer 回调
kCFRunLoopBeforeSources , // 触发 Source0 回调
kCFRunLoopBeforeWaiting , // 等待 mach_port 消息
kCFRunLoopAfterWaiting ), // 接收 mach_port 消息
kCFRunLoopExit , // 退出 loop
kCFRunLoopAllActivities// loop 所有状态改变
}
</pre></div>
<p>我们需要监测的状态有两个：RunLoop 在进入睡眠之前和唤醒后的两个 loop 状态定义的值，分别是 kCFRunLoopBeforeSources 和 kCFRunLoopAfterWaiting ，也就是要触发 Source0 回调和接收 mach_port 消息两个状态。</p>
<p class="maodian"></p><h2>三、如何检查卡顿</h2>
<p>说下步骤：</p>
<p>创建一个 CFRunLoopObserverContext 观察者；</p>
<p>将创建好的观察者 runLoopObserver 添加到主线程 RunLoop 的 common 模式下观察；</p>
<p>创建一个持续的子线程专门用来监控主线程的 RunLoop 状态；</p>
<p>一旦发现进入睡眠前的 kCFRunLoopBeforeSources 状态，或者唤醒后的状态 kCFRunLoopAfterWaiting，在设置的时间阈值内一直没有变化，即可判定为卡顿；</p>
<p>dump 出堆栈的信息，从而进一步分析出具体是哪个方法的执行时间过长；</p>
<p>上代码：</p>
<div class="jb51code"><pre class="brush:cpp;">#import <Foundation/Foundation.h>
@interface SMLagMonitor : NSObject
+ (instancetype)shareInstance;
- (void)beginMonitor; //开始监视卡顿
- (void)endMonitor; //停止监视卡顿
@end
</pre></div>
<div class="jb51code"><pre class="brush:cpp;">#import "SMLagMonitor.h"
#import "SMCallStack.h"
#import "SMCPUMonitor.h"
@interface SMLagMonitor() {
int timeoutCount;
CFRunLoopObserverRef runLoopObserver;
@public
dispatch_semaphore_t dispatchSemaphore;
CFRunLoopActivity runLoopActivity;
}
@property (nonatomic, strong) NSTimer *cpuMonitorTimer;
@end
@implementation SMLagMonitor
#pragma mark - Interface
+ (instancetype)shareInstance {
static id instance = nil;
static dispatch_once_t dispatchOnce;
dispatch_once(&dispatchOnce, ^{
instance = [ init];
});
return instance;
}
- (void)beginMonitor {
//监测 CPU 消耗
self.cpuMonitorTimer = [NSTimer scheduledTimerWithTimeInterval:3
target:self
selector:@selector(updateCPUInfo)
userInfo:nil
repeats:YES];
//监测卡顿
if (runLoopObserver) {
return;
}
dispatchSemaphore = dispatch_semaphore_create(0); //Dispatch Semaphore保证同步
//创建一个观察者
CFRunLoopObserverContext context = {0,(__bridge void*)self,NULL,NULL};
runLoopObserver = CFRunLoopObserverCreate(kCFAllocatorDefault,
kCFRunLoopAllActivities,
YES,
0,
&runLoopObserverCallBack,
&context);
//将观察者添加到主线程runloop的common模式下的观察中
CFRunLoopAddObserver(CFRunLoopGetMain(), runLoopObserver, kCFRunLoopCommonModes);
//创建子线程监控
dispatch_async(dispatch_get_global_queue(0, 0), ^{
//子线程开启一个持续的loop用来进行监控
while (YES) {
long semaphoreWait = dispatch_semaphore_wait(dispatchSemaphore, dispatch_time(DISPATCH_TIME_NOW, 20*NSEC_PER_MSEC));
if (semaphoreWait != 0) {
if (!runLoopObserver) {
timeoutCount = 0;
dispatchSemaphore = 0;
runLoopActivity = 0;
return;
}
//两个runloop的状态，BeforeSources和AfterWaiting这两个状态区间时间能够检测到是否卡顿
if (runLoopActivity == kCFRunLoopBeforeSources || runLoopActivity == kCFRunLoopAfterWaiting) {
// 将堆栈信息上报服务器的代码放到这里
//出现三次出结果
// if (++timeoutCount < 3) {
// continue;
// }
NSLog(@"monitor trigger");
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
// ;
});
} //end activity
}// end semaphore wait
timeoutCount = 0;
}// end while
});
}
- (void)endMonitor {
;
if (!runLoopObserver) {
return;
}
CFRunLoopRemoveObserver(CFRunLoopGetMain(), runLoopObserver, kCFRunLoopCommonModes);
CFRelease(runLoopObserver);
runLoopObserver = NULL;
}
#pragma mark - Private
static void runLoopObserverCallBack(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info){
SMLagMonitor *lagMonitor = (__bridge SMLagMonitor*)info;
lagMonitor->runLoopActivity = activity;
dispatch_semaphore_t semaphore = lagMonitor->dispatchSemaphore;
dispatch_semaphore_signal(semaphore);
}
- (void)updateCPUInfo {
thread_act_array_t threads;
mach_msg_type_number_t threadCount = 0;
const task_t thisTask = mach_task_self();
kern_return_t kr = task_threads(thisTask, &threads, &threadCount);
if (kr != KERN_SUCCESS) {
return;
}
for (int i = 0; i < threadCount; i++) {
thread_info_data_t threadInfo;
thread_basic_info_t threadBaseInfo;
mach_msg_type_number_t threadInfoCount = THREAD_INFO_MAX;
if (thread_info((thread_act_t)threads, THREAD_BASIC_INFO, (thread_info_t)threadInfo, &threadInfoCount) == KERN_SUCCESS) {
threadBaseInfo = (thread_basic_info_t)threadInfo;
if (!(threadBaseInfo->flags & TH_FLAGS_IDLE)) {
integer_t cpuUsage = threadBaseInfo->cpu_usage / 10;
if (cpuUsage > 70) {
//cup 消耗大于 70 时打印和记录堆栈
NSString *reStr = smStackOfThread(threads);
//记录数据库中
// [[ increaseWithStackString:reStr] subscribeNext:^(id x) {}];
NSLog(@"CPU useage overload thread stack：\n%@",reStr);
}
}
}
}
}
@end
</pre></div>
<p>使用，直接在APP didFinishLaunchingWithOptions 方法里面这样写：</p>
<div class="jb51code"><pre class="brush:cpp;">[ beginMonitor];</pre></div>
<p>以上就是ios利用RunLoop原理实现去监控卡顿实例详解的详细内容，更多关于ios RunLoop去监控卡顿的资料请关注琼殿技术社区其它相关文章！</p>
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