Performance monitor

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By this code you can record CPU core load and VM memory usage. The code is tested and works on Android and should works also on Linux, but not on Windows.

/
/**
 * Performance monitor provide you record of CPU cores load and memory usage. Based on <a
 * href="http://kernel.org/doc/Documentation/filesystems/proc.txt">kernel documentation</a>.
 * 
 * @author <a href="http://www.youtube.com/ChladekTomas">Tomáš Chládek</a>
 * @author <a href="http://makingmoneywithandroid.com/forum/member.php?action=profile&uid=1">david</a>
 */
public class PerformanceMonitor extends Thread {
	private RandomAccessFile readStream;
	private final int[][] recordCore;
	private final long[] coreLoadSum;
	private final int[] recordMemory;
	private long memoryUsageCount;
	private final int recordCount;
	private int recordIndex;
	private final long[] totalLast, idleLast;
	private final int updateInterval;
	private final long maxMemory;
	private final int coreCount;
	private final int[] coreLoadMean;
	private int memoryUsageMean;

	private final PerformanceRecord record;
	private int recordPackageIndex;
	private int recordsToSend;

	/**
	 * Creates a new PerformanceMonitor. To start recording you have to call start() method. Number of records is recordTime /
	 * updateInterval.
	 * 
	 * @param recordTime
	 *            record length of CPU cores load and memory usage [ms]
	 * @param updateInterval
	 *            interval between updates [ms]
	 */
	public PerformanceMonitor(int recordTime, int updateInterval) {
		recordsToSend = coreCount = getNumCores();
		recordCount = recordTime / updateInterval;
		recordCore = new int[recordCount][coreCount];
		recordMemory = new int[recordCount];
		this.updateInterval = updateInterval;
		totalLast = new long[coreCount];
		idleLast = new long[coreCount];
		coreLoadSum = new long[coreCount];
		coreLoadMean = new int[coreCount];
		maxMemory = Runtime.getRuntime().maxMemory() / 100;
		record = new PerformanceRecord(coreCount);
	}

	@Override
	public void run() {
		try {
			while (true) {
				recordIndex++;
				if (recordIndex == recordCount)
					recordIndex = 0;
				readCoreLoad();
				readMemoryUsage();
				Thread.sleep(updateInterval);
			}
		} catch (InterruptedException e) {
		}
	}

	/**
	 * Gets the number of physical cores. This includes all cores, not just the ones running at time when method is called.
	 * 
	 * @return number of cores
	 */
	public int getCoreCount() {
		return coreCount;
	}

	/**
	 * Gets the last core load.
	 * 
	 * @param index
	 *            which core do you want?
	 * @return core load [0...100] or -1 if index is out of range [0...PerformanceMonitor.getCoreCount()]
	 */
	public int getLastCoreLoad(int index) {
		if (index >= 0 && index < coreCount)
			return recordCore[recordIndex][index];
		return -1;
	}

	/**
	 * Gets the last memory usage.
	 * 
	 * @return memory usage [0...100]
	 */
	public int getLastMemoryUsage() {
		return recordMemory[recordIndex];
	}

	public PerformanceRecord getNextRecord() {
		recordPackageIndex++;
		if (recordPackageIndex == recordCount)
			recordPackageIndex = 0;
		record.coreLoad = recordCore[recordPackageIndex];
		record.memoryUsage = recordMemory[recordPackageIndex];
		record.recordNumb = recordCount - recordsToSend;
		recordsToSend--;
		return record;
	}

	public boolean hasMoreRecords() {
		if (recordPackageIndex == -1)
			recordPackageIndex = recordIndex;
		if (recordsToSend > 0)
			return true;
		recordPackageIndex = -1;
		recordsToSend = recordCount;
		return false;
	}

	private void readCoreLoad() {
		try {
			readStream = new RandomAccessFile("/proc/stat", "r");
			readStream.readLine();
			int currCoreCount = Runtime.getRuntime().availableProcessors();
			for (int i = 0; i < currCoreCount; i++) {
				String line = readStream.readLine();
				String[] toks = line.split(" ");
				long total = Long.parseLong(toks[1]) + Long.parseLong(toks[2]) + Long.parseLong(toks[3]) + Long.parseLong(toks[5])
						+ Long.parseLong(toks[6]) + Long.parseLong(toks[7]);
				long idle = Long.parseLong(toks[4]);
				int load = (int) ((total - totalLast[i]) * 100f / (total - totalLast[i] + idle - idleLast[i]));
				if (load < 0) // avoid crazy values, when is turn on or turn of CPU core
					load = 0;
				else if (load > 100)
					load = 100;
				coreLoadSum[i] -= recordCore[recordIndex][i];
				recordCore[recordIndex][i] = load;
				totalLast[i] = total;
				idleLast[i] = idle;
				coreLoadSum[i] += load;
				coreLoadMean[i] = (int) (coreLoadSum[i] / recordCount);
			}
			readStream.close();
			if (currCoreCount < coreCount)
				for (int i = currCoreCount; i < coreCount; i++) {
					coreLoadSum[i] -= recordCore[recordIndex][i];
					recordCore[recordIndex][i] = 0;
					coreLoadMean[i] = (int) (coreLoadSum[i] / recordCount);
				}
		} catch (IOException e) {
		}
	}

	private void readMemoryUsage() {
		int memUsage = (int) ((Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) / maxMemory);
		memoryUsageCount -= recordMemory[recordIndex];
		recordMemory[recordIndex] = memUsage;
		memoryUsageCount += memUsage;
		memoryUsageMean = (int) (memoryUsageCount / recordCount);
	}

	/**
	 * Gets the number of cores available in this device, across all processors. Requires: Ability to peruse the filesystem at
	 * "/sys/devices/system/cpu"
	 * 
	 * @return The number of cores, or 1 if failed to get result
	 * 
	 * @author david
	 */
	private int getNumCores() {
		class CpuFilter implements FileFilter { // Private Class to display only CPU devices in the directory listing
			@Override
			public boolean accept(File pathname) {
				if (Pattern.matches("cpu[0-9]", pathname.getName())) // Check if filename is "cpu", followed by a single digit number
					return true;
				return false;
			}
		}
		try {
			File dir = new File("/sys/devices/system/cpu/"); // Get directory containing CPU info
			File[] files = dir.listFiles(new CpuFilter()); // Filter to only list the devices we care about
			return files.length; // Return the number of cores (virtual CPU devices)
		} catch (Exception e) {
			return 1;
		}
	}

	public class PerformanceRecord {
		protected int[] coreLoad;
		protected int memoryUsage;
		protected int recordNumb;

		protected PerformanceRecord(int coreCount) {
			coreLoad = new int[coreCount];
		}

		/**
		 * Gets the core load.
		 * 
		 * @param index
		 *            which core load do you want?
		 * @return core load [0...100] or -1 if index is out of range [0...PerformanceMonitor.getCoreCount()]
		 */
		public int getCoreLoad(int index) {
			if (index >= 0 && index < coreCount)
				return coreLoad[index];
			return -1;
		}

		/**
		 * Gets memory usage.
		 * 
		 * @return memory usage [0...100]
		 */
		public int getMemoryUsage() {
			return memoryUsage;
		}

		/**
		 * Number of this record.
		 * 
		 * @return
		 */
		public int getRecordNumb() {
			return recordNumb;
		}

		/**
		 * Gets mean of core load.
		 * 
		 * @param index
		 *            which mean of core do you want? [0...getCoreCount()]
		 * @return core load [0...100]
		 */
		public int getCoreLoadMean(int index) {
			return coreLoadMean[index];
		}

		/**
		 * Gets the mean of memory usage.
		 * 
		 * @return memory usage [0...100]
		 */
		public int getMemoryUsageMean() {
			return memoryUsageMean;
		}
	}
}