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Implement a exponential backoff for NTP time and XTRA data retry.

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b/21904128

Change-Id: I9fc8917eed3065ff0a4946c5a3bdecb9e93da19d
This commit is contained in:
Wei Liu
2015-06-24 23:47:50 -07:00
parent 001df9ca90
commit 6f6326bc75
1 changed files with 43 additions and 6 deletions
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49
services/core/java/com/android/server/location/GpsLocationProvider.java
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@@ -22,10 +22,8 @@ import com.android.internal.location.GpsNetInitiatedHandler;
import com.android.internal.location.GpsNetInitiatedHandler.GpsNiNotification;
import com.android.internal.location.ProviderProperties;
import com.android.internal.location.ProviderRequest;
import com.android.internal.R;
import com.android.internal.telephony.Phone;
import com.android.internal.telephony.PhoneConstants;
import com.android.internal.telephony.TelephonyIntents;
import android.app.AlarmManager;
import android.app.AppOpsManager;
@@ -72,7 +70,6 @@ import android.provider.Settings;
import android.provider.Telephony.Carriers;
import android.provider.Telephony.Sms.Intents;
import android.telephony.SmsMessage;
import android.telephony.SubscriptionInfo;
import android.telephony.SubscriptionManager;
import android.telephony.SubscriptionManager.OnSubscriptionsChangedListener;
import android.telephony.TelephonyManager;
@@ -91,7 +88,6 @@ import java.io.StringReader;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Date;
import java.util.List;
import java.util.Map.Entry;
import java.util.Properties;
@@ -283,8 +279,16 @@ public class GpsLocationProvider implements LocationProviderInterface {
// current setting 24 hours
private static final long NTP_INTERVAL = 24*60*60*1000;
// how long to wait if we have a network error in NTP or XTRA downloading
// the initial value of the exponential backoff
// current setting - 5 minutes
private static final long RETRY_INTERVAL = 5*60*1000;
// how long to wait if we have a network error in NTP or XTRA downloading
// the max value of the exponential backoff
// current setting - 4 hours
private static final long MAX_RETRY_INTERVAL = 4*60*60*1000;
private BackOff mNtpBackOff = new BackOff(RETRY_INTERVAL, MAX_RETRY_INTERVAL);
private BackOff mXtraBackOff = new BackOff(RETRY_INTERVAL, MAX_RETRY_INTERVAL);
// true if we are enabled, protected by this
private boolean mEnabled;
@@ -877,9 +881,10 @@ public class GpsLocationProvider implements LocationProviderInterface {
native_inject_time(time, timeReference, (int) certainty);
delay = NTP_INTERVAL;
mNtpBackOff.reset();
} else {
if (DEBUG) Log.d(TAG, "requestTime failed");
delay = RETRY_INTERVAL;
delay = mNtpBackOff.nextBackoffMillis();
}
sendMessage(INJECT_NTP_TIME_FINISHED, 0, null);
@@ -920,6 +925,7 @@ public class GpsLocationProvider implements LocationProviderInterface {
Log.d(TAG, "calling native_inject_xtra_data");
}
native_inject_xtra_data(data, data.length);
mXtraBackOff.reset();
}
sendMessage(DOWNLOAD_XTRA_DATA_FINISHED, 0, null);
@@ -927,7 +933,8 @@ public class GpsLocationProvider implements LocationProviderInterface {
if (data == null) {
// try again later
// since this is delayed and not urgent we do not hold a wake lock here
mHandler.sendEmptyMessageDelayed(DOWNLOAD_XTRA_DATA, RETRY_INTERVAL);
mHandler.sendEmptyMessageDelayed(DOWNLOAD_XTRA_DATA,
mXtraBackOff.nextBackoffMillis());
}
// release wake lock held by task
@@ -2147,6 +2154,36 @@ public class GpsLocationProvider implements LocationProviderInterface {
pw.append(s);
}
/**
* A simple implementation of exponential backoff.
*/
private static final class BackOff {
private static final int MULTIPLIER = 2;
private final long mInitIntervalMillis;
private final long mMaxIntervalMillis;
private long mCurrentIntervalMillis;
public BackOff(long initIntervalMillis, long maxIntervalMillis) {
mInitIntervalMillis = initIntervalMillis;
mMaxIntervalMillis = maxIntervalMillis;
mCurrentIntervalMillis = mInitIntervalMillis / MULTIPLIER;
}
public long nextBackoffMillis() {
if (mCurrentIntervalMillis > mMaxIntervalMillis) {
return mMaxIntervalMillis;
}
mCurrentIntervalMillis *= MULTIPLIER;
return mCurrentIntervalMillis;
}
public void reset() {
mCurrentIntervalMillis = mInitIntervalMillis / MULTIPLIER;
}
}
// for GPS SV statistics
private static final int MAX_SVS = 32;
private static final int EPHEMERIS_MASK = 0;