Use varint to record cpu usage data and measured energy in battery history (d8371008) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/os/BatteryStatsHistory.java

+74 −7

Original line number	Diff line number	Diff line
		@@ -79,7 +79,7 @@ public class BatteryStatsHistory {
		private static final String TAG = "BatteryStatsHistory";

		// Current on-disk Parcel version. Must be updated when the format of the parcelable changes
		private static final int VERSION = 208;
		private static final int VERSION = 209;

		private static final String HISTORY_DIR = "battery-history";
		private static final String FILE_SUFFIX = ".bin";
		@@ -198,6 +198,7 @@ public class BatteryStatsHistory {
		private long mHistoryBaseTimeMs;
		private boolean mMeasuredEnergyHeaderWritten = false;
		private boolean mCpuUsageHeaderWritten = false;
		private final VarintParceler mVarintParceler = new VarintParceler();

		private byte mLastHistoryStepLevel = 0;

		@@ -1665,9 +1666,7 @@ public class BatteryStatsHistory {
		}
		mMeasuredEnergyHeaderWritten = true;
		}
		for (long chargeUC : cur.measuredEnergyDetails.chargeUC) {
		dest.writeLong(chargeUC);
		}
		mVarintParceler.writeLongArray(dest, cur.measuredEnergyDetails.chargeUC);
		}

		if (cur.cpuUsageDetails != null) {
		@@ -1679,9 +1678,7 @@ public class BatteryStatsHistory {
		mCpuUsageHeaderWritten = true;
		}
		dest.writeInt(cur.cpuUsageDetails.uid);
		for (long cpuUsageMs: cur.cpuUsageDetails.cpuUsageMs) {
		dest.writeLong(cpuUsageMs);
		}
		mVarintParceler.writeLongArray(dest, cur.cpuUsageDetails.cpuUsageMs);
		}
		}
		}
		@@ -1930,4 +1927,74 @@ public class BatteryStatsHistory {
		entry.getKey());
		}
		}

		/**
		* Writes/reads an array of longs into Parcel using a compact format, where small integers use
		* fewer bytes. It is a bit more expensive than just writing the long into the parcel,
		* but at scale saves a lot of storage and allows recording of longer battery history.
		*/
		@VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
		public static final class VarintParceler {
		/**
		* Writes an array of longs into Parcel using the varint format, see
		* https://developers.google.com/protocol-buffers/docs/encoding#varints
		*/
		public void writeLongArray(Parcel parcel, long[] values) {
		int out = 0;
		int shift = 0;
		for (long value : values) {
		boolean done = false;
		while (!done) {
		final byte b;
		if ((value & ~0x7FL) == 0) {
		b = (byte) value;
		done = true;
		} else {
		b = (byte) (((int) value & 0x7F) \| 0x80);
		value >>>= 7;
		}
		if (shift == 32) {
		parcel.writeInt(out);
		shift = 0;
		out = 0;
		}
		out \|= (b & 0xFF) << shift;
		shift += 8;
		}
		}
		if (shift != 0) {
		parcel.writeInt(out);
		}
		}

		/**
		* Reads a long written with {@link #writeLongArray}
		*/
		public void readLongArray(Parcel parcel, long[] values) {
		int in = parcel.readInt();
		int available = 4;
		for (int i = 0; i < values.length; i++) {
		long result = 0;
		int shift;
		for (shift = 0; shift < 64; shift += 7) {
		if (available == 0) {
		in = parcel.readInt();
		available = 4;
		}
		final byte b = (byte) in;
		in >>= 8;
		available--;

		result \|= (long) (b & 0x7F) << shift;
		if ((b & 0x80) == 0) {
		values[i] = result;
		break;
		}
		}
		if (shift >= 64) {
		throw new ParcelFormatException("Invalid varint format");
		}
		}
		}
		}
		}

core/java/com/android/internal/os/BatteryStatsHistoryIterator.java

+5 −7

Original line number	Diff line number	Diff line
		@@ -35,6 +35,8 @@ public class BatteryStatsHistoryIterator {
		private final SparseArray<BatteryStats.HistoryTag> mHistoryTags = new SparseArray<>();
		private BatteryStats.MeasuredEnergyDetails mMeasuredEnergyDetails;
		private BatteryStats.CpuUsageDetails mCpuUsageDetails;
		private final BatteryStatsHistory.VarintParceler mVarintParceler =
		new BatteryStatsHistory.VarintParceler();

		public BatteryStatsHistoryIterator(@NonNull BatteryStatsHistory history) {
		mBatteryStatsHistory = history;
		@@ -61,7 +63,7 @@ public class BatteryStatsHistoryIterator {
		return true;
		}

		void readHistoryDelta(Parcel src, BatteryStats.HistoryItem cur) {
		private void readHistoryDelta(Parcel src, BatteryStats.HistoryItem cur) {
		int firstToken = src.readInt();
		int deltaTimeToken = firstToken & BatteryStatsHistory.DELTA_TIME_MASK;
		cur.cmd = BatteryStats.HistoryItem.CMD_UPDATE;
		@@ -226,9 +228,7 @@ public class BatteryStatsHistoryIterator {
		throw new IllegalStateException("MeasuredEnergyDetails without a header");
		}

		for (int i = 0; i < mMeasuredEnergyDetails.chargeUC.length; i++) {
		mMeasuredEnergyDetails.chargeUC[i] = src.readLong();
		}
		mVarintParceler.readLongArray(src, mMeasuredEnergyDetails.chargeUC);
		cur.measuredEnergyDetails = mMeasuredEnergyDetails;
		} else {
		cur.measuredEnergyDetails = null;
		@@ -249,9 +249,7 @@ public class BatteryStatsHistoryIterator {
		}

		mCpuUsageDetails.uid = src.readInt();
		for (int i = 0; i < mCpuUsageDetails.cpuUsageMs.length; i++) {
		mCpuUsageDetails.cpuUsageMs[i] = src.readLong();
		}
		mVarintParceler.readLongArray(src, mCpuUsageDetails.cpuUsageMs);
		cur.cpuUsageDetails = mCpuUsageDetails;
		} else {
		cur.cpuUsageDetails = null;

services/tests/servicestests/src/com/android/server/power/stats/BatteryStatsHistoryTest.java

+64 −0

Original line number	Diff line number	Diff line
		@@ -382,4 +382,68 @@ public class BatteryStatsHistoryTest {
		pw.flush();
		return writer.toString();
		}

		@Test
		public void testVarintParceler() {
		long[] values = {
		0,
		1,
		42,
		0x1234,
		0x10000000,
		0x12345678,
		0x7fffffff,
		0xffffffffL,
		0x100000000000L,
		0x123456789012L,
		0x1000000000000000L,
		0x1234567890123456L,
		0x7fffffffffffffffL,
		0xffffffffffffffffL};

		// Parcel subarrays of different lengths and assert the size of the resulting parcel
		testVarintParceler(Arrays.copyOfRange(values, 0, 1), 4); // v. 8
		testVarintParceler(Arrays.copyOfRange(values, 0, 2), 4); // v. 16
		testVarintParceler(Arrays.copyOfRange(values, 0, 3), 4); // v. 24
		testVarintParceler(Arrays.copyOfRange(values, 0, 4), 8); // v. 32
		testVarintParceler(Arrays.copyOfRange(values, 0, 5), 12); // v. 40
		testVarintParceler(Arrays.copyOfRange(values, 0, 6), 16); // v. 48
		testVarintParceler(Arrays.copyOfRange(values, 0, 7), 20); // v. 56
		testVarintParceler(Arrays.copyOfRange(values, 0, 8), 28); // v. 64
		testVarintParceler(Arrays.copyOfRange(values, 0, 9), 32); // v. 72
		testVarintParceler(Arrays.copyOfRange(values, 0, 10), 40); // v. 80
		testVarintParceler(Arrays.copyOfRange(values, 0, 11), 48); // v. 88
		testVarintParceler(Arrays.copyOfRange(values, 0, 12), 60); // v. 96
		testVarintParceler(Arrays.copyOfRange(values, 0, 13), 68); // v. 104
		testVarintParceler(Arrays.copyOfRange(values, 0, 14), 76); // v. 112
		}

		private void testVarintParceler(long[] values, int expectedLength) {
		BatteryStatsHistory.VarintParceler parceler = new BatteryStatsHistory.VarintParceler();
		Parcel parcel = Parcel.obtain();
		parcel.writeString("begin");
		int pos = parcel.dataPosition();
		parceler.writeLongArray(parcel, values);
		int length = parcel.dataPosition() - pos;
		parcel.writeString("end");

		byte[] bytes = parcel.marshall();
		parcel.recycle();

		parcel = Parcel.obtain();
		parcel.unmarshall(bytes, 0, bytes.length);
		parcel.setDataPosition(0);

		assertThat(parcel.readString()).isEqualTo("begin");

		long[] result = new long[values.length];
		parceler.readLongArray(parcel, result);

		assertThat(result).isEqualTo(values);
		assertThat(length).isEqualTo(expectedLength);

		assertThat(parcel.readString()).isEqualTo("end");

		parcel.recycle();
		}
		}