How to collect the usage of CPU. Collect the usage of each thread.

CPU Usage.m

- (integer_t)checkCPUUsage {
    thread_act_array_t threads;
    mach_msg_type_number_t threadCount = 0;
    
    const task_t thisTask = mach_task_self_;
    
    kern_return_t ret = task_threads(thisTask, &threads, &threadCount);
    if (ret != KERN_SUCCESS) {
        return 0;
    }
    
    integer_t cpuUsage = 0;
    for (int i = 0; i < threadCount; i++) {
        thread_info_data_t threadInfo;
        thread_basic_info_t threadBasicInfo;
        mach_msg_type_number_t threadInfoCount = THREAD_INFO_MAX;
        if (thread_info(threads[i], THREAD_BASIC_INFO, threadInfo, &threadInfoCount)) {
            
            threadBasicInfo = (thread_basic_info_t)threadInfo;
            if (!(threadBasicInfo->flags & TH_FLAGS_IDLE)) {
                cpuUsage += threadBasicInfo->cpu_usage;
            }
        }
    }
    assert(vm_deallocate(mach_task_self_, (vm_address_t)threads, threadCount * sizeof(thread_t)) == KERN_SUCCESS);
    return cpuUsage;
}