floatcpu_usage()

{

    kern_return_t kr;

    task_info_data_t tinfo;

    mach_msg_type_number_t task_info_count;

    task_info_count = TASK_INFO_MAX;

    kr = task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)tinfo, &task_info_count);

    if(kr !=KERN_SUCCESS) {

        return-1;

    }

    task_basic_info_t      basic_info;

    thread_array_t        thread_list;

    mach_msg_type_number_t thread_count;

    thread_info_data_t    thinfo;

    mach_msg_type_number_t thread_info_count;

    thread_basic_info_t basic_info_th;

    uint32_t stat_thread =0;// Mach threads

    basic_info = (task_basic_info_t)tinfo;

    // get threads in the task

    kr = task_threads(mach_task_self(), &thread_list, &thread_count);

    if(kr !=KERN_SUCCESS) {

        return-1;

    }

    if(thread_count >0)

        stat_thread += thread_count;

    longtot_sec =0;

    longtot_usec =0;

    floattot_cpu =0;

    intj;

    for(j =0; j < (int)thread_count; j++)

    {

        thread_info_count = THREAD_INFO_MAX;

        kr = thread_info(thread_list[j], THREAD_BASIC_INFO,

                         (thread_info_t)thinfo, &thread_info_count);

        if(kr !=KERN_SUCCESS) {

            return-1;

        }

        basic_info_th = (thread_basic_info_t)thinfo;

        if(!(basic_info_th->flags & TH_FLAGS_IDLE)) {

            tot_sec = tot_sec + basic_info_th->user_time.seconds + basic_info_th->system_time.seconds;

            tot_usec = tot_usec + basic_info_th->user_time.microseconds + basic_info_th->system_time.microseconds;

            tot_cpu = tot_cpu + basic_info_th->cpu_usage / (float)TH_USAGE_SCALE *100.0;

        }

    }// for each thread

    kr = vm_deallocate(mach_task_self(), (vm_offset_t)thread_list, thread_count *sizeof(thread_t));

    assert(kr == KERN_SUCCESS);

    returntot_cpu;

}