余辉 -
获取 CPU 核数 Linux 中的设备都是以文件的形式存在，CPU 也不例外，因此 CPU 的文件个数就等价与核数。 Android 的 CPU 设备文件位于/sys/devices/system/cpu/目录，文件名的的格式为cpud+。 root@generic_x86_64:/sys/devices/system/cpu # ls cpu0 cpufreq cpuidle kernel_max modalias offline online possible power present uevent 统计一下文件个数便可以获得 CPU 核数。 public static int getNumberOfCPUCores() { if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD_MR1) { // Gingerbread doesn"t support giving a single application access to both cores, but a // handful of devices (Atrix 4G and Droid X2 for example) were released with a dual-core // chipset and Gingerbread; that can let an app in the background run without impacting // the foreground application. But for our purposes, it makes them single core. return 1; } int cores; try { cores = new File("/sys/devices/system/cpu/").listFiles(CPU_FILTER).length; } catch (SecurityException e) { cores = DEVICEINFO_UNKNOWN; } catch (NullPointerException e) { cores = DEVICEINFO_UNKNOWN; } return cores; } private static final FileFilter CPU_FILTER = new FileFilter() { @Override public boolean accept(File pathname) { String path = pathname.getName(); //regex is slow, so checking char by char. if (path.startsWith("cpu")) { for (int i = 3; i < path.length(); i++) { if (path.charAt(i) < "0" path.charAt(i) > "9") { return false; } } return true; } return false; } }; 获取时钟频率 获取时钟频率需要读取系统文件 -/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq或者/proc/cpuinfo。 Android 模拟器中并没有cpuinfo_max_freq文件，因此只能读取/proc/cpuinfo。 /proc/cpuinfo包含了很多 cpu 数据。 processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 70 model name : Intel(R) Core(TM) i7-4770HQ CPU @ 2.20GHz stepping : 1 cpu MHz : 0.000 cache size : 1024 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 4 wp : yes 代码如下： public static int getCPUMaxFreqKHz() { int maxFreq = DEVICEINFO_UNKNOWN; try { for (int i = 0; i < getNumberOfCPUCores(); i++) { String filename = "/sys/devices/system/cpu/cpu" + i + "/cpufreq/cpuinfo_max_freq"; File cpuInfoMaxFreqFile = new File(filename); if (cpuInfoMaxFreqFile.exists()) { byte[] buffer = new byte[128]; FileInputStream stream = new FileInputStream(cpuInfoMaxFreqFile); try { stream.read(buffer); int endIndex = 0; //Trim the first number out of the byte buffer. while (buffer[endIndex] >= "0" && buffer[endIndex] <= "9" && endIndex < buffer.length) endIndex++; String str = new String(buffer, 0, endIndex); Integer freqBound = Integer.parseInt(str); if (freqBound > maxFreq) maxFreq = freqBound; } catch (NumberFormatException e) { //Fall through and use /proc/cpuinfo. } finally { stream.close(); } } } if (maxFreq == DEVICEINFO_UNKNOWN) { FileInputStream stream = new FileInputStream("/proc/cpuinfo"); try { int freqBound = parseFileForValue("cpu MHz", stream); freqBound *= 1000; //MHz -> kHz if (freqBound > maxFreq) maxFreq = freqBound; } finally { stream.close(); } } } catch (IOException e) { maxFreq = DEVICEINFO_UNKNOWN; //Fall through and return unknown. } return maxFreq; } 获取内存大小 如果 SDK 版本大于等于JELLY_BEAN，可以通过ActivityManager来获取内从大小。 ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo(); ActivityManager am = (ActivityManager) c.getSystemService(Context.ACTIVITY_SERVICE); am.getMemoryInfo(memInfo); 如果版本低于JELLY_BEAN，则只能读取系统文件了。 FileInputStream stream = new FileInputStream("/proc/meminfo"); totalMem = parseFileForValue("MemTotal", stream); 完整代码如下： @TargetApi(Build.VERSION_CODES.JELLY_BEAN) public static long getTotalMemory(Context c) { // memInfo.totalMem not supported in pre-Jelly Bean APIs. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo(); ActivityManager am = (ActivityManager) c.getSystemService(Context.ACTIVITY_SERVICE); am.getMemoryInfo(memInfo); if (memInfo != null) { return memInfo.totalMem; } else { return DEVICEINFO_UNKNOWN; } } else { long totalMem = DEVICEINFO_UNKNOWN; try { FileInputStream stream = new FileInputStream("/proc/meminfo"); try { totalMem = parseFileForValue("MemTotal", stream); totalMem *= 1024; } finally { stream.close(); } } catch (IOException e) { } return totalMem; } }