线程的优先级

NSThread *t1 = [[NSThread alloc] initWithTarget:self selector:@selector(createThreadOne) object:nil];
t1.name = @"线程A";
//修改优先级
t1.threadPriority = 0;
[t1 start];

NSThread *t2 = [[NSThread alloc] initWithTarget:self selector:@selector(createThreadTwo) object:nil];
t2.name = @"线程B";
t2.threadPriority = 1;
[t2 start];