查看设备几核的方法

- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"%d",countOfCores());
}

unsigned int countOfCores() {
    unsigned int ncpu;
    size_t len = sizeof(ncpu);
    sysctlbyname("hw.ncpu",&ncpu,&len,NULL,0);
    return ncpu;
}