Objective-C/iOS CPU的使用率

获取App的CPU使用率：

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;

long tot_sec = 0;
long tot_usec = 0;
float tot_cpu = 0;
int j;

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);

return tot_cpu;

获取系统单核CPU的使用率：

processor_info_array_t _cpuInfo, _prevCPUInfo = nil;
mach_msg_type_number_t _numCPUInfo, _numPrevCPUInfo = 0;
unsigned _numCPUs;
NSLock *_cpuUsageLock;

int _mib[2U] = { CTL_HW, HW_NCPU };
size_t _sizeOfNumCPUs = sizeof(_numCPUs);
int _status = sysctl(_mib, 2U, &_numCPUs, &_sizeOfNumCPUs, NULL, 0U);
if(_status)
    _numCPUs = 1;

_cpuUsageLock = [[NSLock alloc] init];

natural_t _numCPUsU = 0U;
kern_return_t err = host_processor_info(mach_host_self(), PROCESSOR_CPU_LOAD_INFO, &_numCPUsU, &_cpuInfo, &_numCPUInfo);
if(err == KERN_SUCCESS) {
    [_cpuUsageLock lock];
    
    for(unsigned i = 0U; i < _numCPUs; ++i) {
        Float32 _inUse, _total;
        if(_prevCPUInfo) {
            _inUse = (
                      (_cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_USER]   - _prevCPUInfo[(CPU_STATE_MAX * i) + CPU_STATE_USER])
                      + (_cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_SYSTEM] - _prevCPUInfo[(CPU_STATE_MAX * i) + CPU_STATE_SYSTEM])
                      + (_cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_NICE]   - _prevCPUInfo[(CPU_STATE_MAX * i) + CPU_STATE_NICE])
                      );
            _total = _inUse + (_cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_IDLE] - _prevCPUInfo[(CPU_STATE_MAX * i) + CPU_STATE_IDLE]);
        } else {
            _inUse = _cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_USER] + _cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_SYSTEM] + _cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_NICE];
            _total = _inUse + _cpuInfo[(CPU_STATE_MAX * i) + CPU_STATE_IDLE];
        }
        
        NSLog(@"CPU核 : %u, 使用: %f%%", i, _inUse / _total * 100.f);
    }
    
    [_cpuUsageLock unlock];
    
    if(_prevCPUInfo) {
        size_t prevCpuInfoSize = sizeof(integer_t) * _numPrevCPUInfo;
        vm_deallocate(mach_task_self(), (vm_address_t)_prevCPUInfo, prevCpuInfoSize);
    }
    
    _prevCPUInfo = _cpuInfo;
    _numPrevCPUInfo = _numCPUInfo;
    
    _cpuInfo = nil;
    _numCPUInfo = 0U;
} else {
    NSLog(@"Error!");
}

以上方法需要引入如下头文件：

#import <mach/mach.h>
#import <sys/sysctl.h>