Merge \"assume a generous prior in the rate estimator\" into nyc-dev (02af0f32) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/notification/NotificationManagerService.java

+2 −0

Original line number	Diff line number	Diff line
		@@ -2521,6 +2521,8 @@ public class NotificationManagerService extends SystemService {
		return;
		}

		mUsageStats.registerEnqueuedByApp(pkg);

		// Limit the number of notifications that any given package except the android
		// package or a registered listener can enqueue. Prevents DOS attacks and deals with leaks.
		if (!isSystemNotification && !isNotificationFromListener) {

services/core/java/com/android/server/notification/NotificationUsageStats.java

+17 −0

Original line number	Diff line number	Diff line
		@@ -113,6 +113,17 @@ public class NotificationUsageStats {
		}
		}

		/**
		* Called when a notification is tentatively enqueued by an app, before rate checking.
		*/
		public synchronized void registerEnqueuedByApp(String packageName) {
		AggregatedStats[] aggregatedStatsArray = getAggregatedStatsLocked(packageName);
		for (AggregatedStats stats : aggregatedStatsArray) {
		stats.numEnqueuedByApp++;
		}
		releaseAggregatedStatsLocked(aggregatedStatsArray);
		}

		/**
		* Called when a notification has been posted.
		*/
		@@ -344,6 +355,7 @@ public class NotificationUsageStats {
		private AggregatedStats mPrevious;

		// ---- Updated as the respective events occur.
		public int numEnqueuedByApp;
		public int numPostedByApp;
		public int numUpdatedByApp;
		public int numRemovedByApp;
		@@ -470,6 +482,7 @@ public class NotificationUsageStats {

		public void emit() {
		AggregatedStats previous = getPrevious();
		maybeCount("note_enqueued", (numEnqueuedByApp - previous.numEnqueuedByApp));
		maybeCount("note_post", (numPostedByApp - previous.numPostedByApp));
		maybeCount("note_update", (numUpdatedByApp - previous.numUpdatedByApp));
		maybeCount("note_remove", (numRemovedByApp - previous.numRemovedByApp));
		@@ -501,6 +514,7 @@ public class NotificationUsageStats {
		quietImportance.maybeCount(previous.quietImportance);
		finalImportance.maybeCount(previous.finalImportance);

		previous.numEnqueuedByApp = numEnqueuedByApp;
		previous.numPostedByApp = numPostedByApp;
		previous.numUpdatedByApp = numUpdatedByApp;
		previous.numRemovedByApp = numRemovedByApp;
		@@ -568,6 +582,8 @@ public class NotificationUsageStats {
		output.append(indentPlusTwo);
		output.append("key='").append(key).append("',\n");
		output.append(indentPlusTwo);
		output.append("numEnqueuedByApp=").append(numEnqueuedByApp).append(",\n");
		output.append(indentPlusTwo);
		output.append("numPostedByApp=").append(numPostedByApp).append(",\n");
		output.append(indentPlusTwo);
		output.append("numUpdatedByApp=").append(numUpdatedByApp).append(",\n");
		@@ -631,6 +647,7 @@ public class NotificationUsageStats {
		JSONObject dump = new JSONObject();
		dump.put("key", key);
		dump.put("duration", SystemClock.elapsedRealtime() - mCreated);
		maybePut(dump, "numEnqueuedByApp", numEnqueuedByApp);
		maybePut(dump, "numPostedByApp", numPostedByApp);
		maybePut(dump, "numUpdatedByApp", numUpdatedByApp);
		maybePut(dump, "numRemovedByApp", numRemovedByApp);

services/core/java/com/android/server/notification/RateEstimator.java

+6 −7

Original line number	Diff line number	Diff line
		@@ -26,9 +26,12 @@ public class RateEstimator {
		private static final double RATE_ALPHA = 0.8;
		private static final double MINIMUM_DT = 0.0005;
		private Long mLastEventTime;
		private Float mInterarrivalTime;
		private double mInterarrivalTime;

		public RateEstimator() {}
		public RateEstimator() {
		// assume something generous if we have no information
		mInterarrivalTime = 1000.0;
		}

		/** Update the estimate to account for an event that just happened. */
		public float update(long now) {
		@@ -38,7 +41,7 @@ public class RateEstimator {
		rate = 0f;
		} else {
		// Calculate the new inter-arrival time based on last event time.
		mInterarrivalTime = (float) getInterarrivalEstimate(now);
		mInterarrivalTime = getInterarrivalEstimate(now);
		rate = (float) (1.0 / mInterarrivalTime);
		}
		mLastEventTime = now;
		@@ -57,10 +60,6 @@ public class RateEstimator {
		private double getInterarrivalEstimate(long now) {
		double dt = ((double) (now - mLastEventTime)) / 1000.0;
		dt = Math.max(dt, MINIMUM_DT);
		if (mInterarrivalTime == null) {
		// No last inter-arrival time, return the new value directly.
		return dt;
		}
		// aiat_old + (1-a)(t_now-t_last)
		return (RATE_ALPHA * mInterarrivalTime + (1.0 - RATE_ALPHA) * dt);
		}

services/tests/servicestests/src/com/android/server/notification/RateEstimatorTest.java

+18 −2

Original line number	Diff line number	Diff line
		@@ -58,6 +58,15 @@ public class RateEstimatorTest extends AndroidTestCase {
		assertFalse(Float.isNaN(rate));
		}

		@SmallTest
		public void testInstantaneousBurstIsEstimatedUnderTwoPercent() throws Exception {
		assertUpdateTime(mTestStartTime);
		long eventStart = mTestStartTime + 1000; // start event a long time after initialization
		long nextEventTime = postEvents(eventStart, 0, 5); // five events at \inf
		final float rate = mEstimator.getRate(nextEventTime);
		assertLessThan("Rate", rate, 20f);
		}

		@SmallTest
		public void testCompactBurstIsEstimatedUnderTwoPercent() throws Exception {
		assertUpdateTime(mTestStartTime);
		@@ -110,12 +119,19 @@ public class RateEstimatorTest extends AndroidTestCase {
		assertLessThan("Rate", rate, 0.1f);
		}

		@SmallTest
		public void testGetRateWithOneUpdate() throws Exception {
		assertUpdateTime(mTestStartTime);
		final float rate = mEstimator.getRate(mTestStartTime+1);
		assertLessThan("Rate", rate, 1f);
		}

		private void assertLessThan(String label, float a, float b) {
		assertTrue(String.format("%s was %f, but should be less than %f", label, a, b), a < b);
		assertTrue(String.format("%s was %f, but should be less than %f", label, a, b), a <= b);
		}

		private void assertGreaterThan(String label, float a, float b) {
		assertTrue(String.format("%s was %f, but should be more than %f", label, a, b), a > b);
		assertTrue(String.format("%s was %f, but should be more than %f", label, a, b), a >= b);
		}

		/** @returns the next event time. */