MainThreadProfie.h

@interface PingThread : NSThread
@property (nonatomic, assign) BOOL pingTaskIsRunning;
@property (nonatomic, strong) dispatch_semaphore_t semaphore;
@end

MainThreadProfier.m

@implementation PingThread

- (void)main {
    self.semaphore = dispatch_semaphore_create(0);
    self.pingTaskIsRunning = NO;
    while (NO == self.isCancelled) {
        self.pingTaskIsRunning = YES;
        dispatch_async(dispatch_get_main_queue(), ^{
            self.pingTaskIsRunning = false;
            dispatch_semaphore_signal(self.semaphore);
        });
        
        [NSThread sleepForTimeInterval:0.4];
        
        if (YES == self.pingTaskIsRunning) {
            NSLog(@"handle the operation here");
        }
        
        dispatch_semaphore_wait(self.semaphore, DISPATCH_TIME_FOREVER);
    }
}

@end