一善延、應(yīng)用CPU實(shí)時(shí)統(tǒng)計(jì)

1.1CPU總使用情況

在proc/stat下有當(dāng)前設(shè)備詳細(xì)的CPU使用情況.詳細(xì)格式如下:

CPU 152342 1421 28562 1600830 12389 553 273 0 0

CPU后面的幾位數(shù)字的含義分別是

user 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻，處于用戶態(tài)的運(yùn)行時(shí)間庶柿，不包含 nice值為負(fù)進(jìn)程。
nice 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻褥伴，nice值為負(fù)的進(jìn)程所占用的CPU時(shí)間
system 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻返吻，處于核心態(tài)的運(yùn)行時(shí)間
idle 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻萧恕，除IO等待時(shí)間以外的其它等待時(shí)間
iowait 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻刚梭，IO等待時(shí)間
irq 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻肠阱，硬中斷時(shí)間
softirq 從系統(tǒng)啟動(dòng)開始累計(jì)到當(dāng)前時(shí)刻票唆，軟中斷時(shí)間

所以totalCpuTime這個(gè)7個(gè)屬性的和.

1.2當(dāng)前應(yīng)用的CPU使用情況

/proc/pid/stat下則是該pid的CPU使用情況.詳細(xì)格式如下:

2341 (com.xxxx.xxxx) S 1131 1131 0 0 -1 3912246 12450 0 2 0 3321 612 0 0 20 0

其中3321 612的含義分別是:

3321：utime 該任務(wù)在用戶運(yùn)行狀態(tài)的時(shí)間
612：stime 該任務(wù)在核心運(yùn)行的時(shí)間

所以processCpuTime為這個(gè)兩個(gè)個(gè)屬性的和.

1.3應(yīng)用的CPU占用

當(dāng)前應(yīng)用所占CPU的算法是:

100*(processCpuTimeNow - processCpuTimeLast)/(totalCpuTimeNow - totalCpuTimeLast)

二、應(yīng)用內(nèi)存占用統(tǒng)計(jì)

統(tǒng)計(jì)當(dāng)前應(yīng)用的內(nèi)存占用的方式：
（1）從ActivityManager獲得MemoryInfo
（2）從MemoryInfo里獲得TotalPss：memInfo[0].getTotalPss()屹徘，其中TotalPss = dalvikPss + nativePss + otherPss

三走趋、DEMO

開啟一個(gè)周期性的任務(wù)打印實(shí)時(shí)CPU和內(nèi)存占用
源碼地址：https://github.com/hello2mao/CPUMemDemo

/**
 * Usage:
 *  Sampler.getInstance().init(getApplicationContext(), 100L);
 *  Sampler.getInstance().start();
 */
public class Sampler implements Runnable {

    private volatile static Sampler instance = null;
    private ScheduledExecutorService scheduler;
    private ActivityManager activityManager;
    private long freq;
    private Long lastCpuTime;
    private Long lastAppCpuTime;
    private RandomAccessFile procStatFile;
    private RandomAccessFile appStatFile;

    private Sampler() {
        scheduler = Executors.newSingleThreadScheduledExecutor();
    }

    public static Sampler getInstance() {
        if (instance == null) {
            synchronized (Sampler.class) {
                if (instance == null) {
                    instance = new Sampler();
                }
            }
        }
        return instance;
    }

    // freq為采樣周期
    public void init(Context context, long freq) {
        activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
        this.freq = freq;
    }

    public void start() {
        scheduler.scheduleWithFixedDelay(this, 0L, freq, TimeUnit.MILLISECONDS);
    }

    @Override
    public void run() {
        double cpu = sampleCPU();
        double mem = sampleMemory();
        Log.d("Sampler", "CPU: " + cpu + "%" + "    Memory: " + mem + "MB");
    }

    private double sampleCPU() {
        long cpuTime;
        long appTime;
        double sampleValue = 0.0D;
        try {
            if (procStatFile == null || appStatFile == null) {
                procStatFile = new RandomAccessFile("/proc/stat", "r");
                appStatFile = new RandomAccessFile("/proc/" + Process.myPid() + "/stat", "r");
            } else {
                procStatFile.seek(0L);
                appStatFile.seek(0L);
            }
            String procStatString = procStatFile.readLine();
            String appStatString = appStatFile.readLine();
            String procStats[] = procStatString.split(" ");
            String appStats[] = appStatString.split(" ");
            cpuTime = Long.parseLong(procStats[2]) + Long.parseLong(procStats[3])
                    + Long.parseLong(procStats[4]) + Long.parseLong(procStats[5])
                    + Long.parseLong(procStats[6]) + Long.parseLong(procStats[7])
                    + Long.parseLong(procStats[8]);
            appTime = Long.parseLong(appStats[13]) + Long.parseLong(appStats[14]);
            if (lastCpuTime == null && lastAppCpuTime == null) {
                lastCpuTime = cpuTime;
                lastAppCpuTime = appTime;
                return sampleValue;
            }
            sampleValue = ((double) (appTime - lastAppCpuTime) / (double) (cpuTime - lastCpuTime)) * 100D;
            lastCpuTime = cpuTime;
            lastAppCpuTime = appTime;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sampleValue;
    }

    private double sampleMemory() {
        double mem = 0.0D;
        try {
            // 統(tǒng)計(jì)進(jìn)程的內(nèi)存信息 totalPss
            final Debug.MemoryInfo[] memInfo = activityManager.getProcessMemoryInfo(new int[]{Process.myPid()});
            if (memInfo.length > 0) {
                // TotalPss = dalvikPss + nativePss + otherPss, in KB
                final int totalPss = memInfo[0].getTotalPss();
                if (totalPss >= 0) {
                    // Mem in MB
                    mem = totalPss / 1024.0D;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return mem;
    }
}