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Merge change Icbb3aa0a into eclair

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* changes:
  Use setRepeating() rather than setInexactRepeating() for backup scheduling, and add some random fuzz to the scheduling times, to make sure we aren't creating hour-aligned server load spikes.
This commit is contained in:
Android (Google) Code Review
2009-11-02 16:58:26 -05:00
parent cce9f0fa86 c1c49c024f
commit afd81beb33
1 changed files with 13 additions and 3 deletions
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16
services/java/com/android/server/BackupManagerService.java
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@@ -76,6 +76,7 @@ import java.util.HashMap;
import java.util.HashSet; import java.util.HashSet;
import java.util.List; import java.util.List;
import java.util.Map; import java.util.Map;
import java.util.Random;
class BackupManagerService extends IBackupManager.Stub { class BackupManagerService extends IBackupManager.Stub {
private static final String TAG = "BackupManagerService"; private static final String TAG = "BackupManagerService";
@@ -85,6 +86,9 @@ class BackupManagerService extends IBackupManager.Stub {
// trigger an immediate pass. // trigger an immediate pass.
private static final long BACKUP_INTERVAL = AlarmManager.INTERVAL_HOUR; private static final long BACKUP_INTERVAL = AlarmManager.INTERVAL_HOUR;
// Random variation in backup scheduling time to avoid server load spikes
private static final int FUZZ_MILLIS = 5 * 60 * 1000;
// The amount of time between the initial provisioning of the device and // The amount of time between the initial provisioning of the device and
// the first backup pass. // the first backup pass.
private static final long FIRST_BACKUP_INTERVAL = 12 * AlarmManager.INTERVAL_HOUR; private static final long FIRST_BACKUP_INTERVAL = 12 * AlarmManager.INTERVAL_HOUR;
@@ -1949,9 +1953,15 @@ class BackupManagerService extends IBackupManager.Stub {
} }
private void startBackupAlarmsLocked(long delayBeforeFirstBackup) { private void startBackupAlarmsLocked(long delayBeforeFirstBackup) {
long when = System.currentTimeMillis() + delayBeforeFirstBackup; // We used to use setInexactRepeating(), but that may be linked to
mAlarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, when, // backups running at :00 more often than not, creating load spikes.
BACKUP_INTERVAL, mRunBackupIntent); // Schedule at an exact time for now, and also add a bit of "fuzz".
Random random = new Random();
long when = System.currentTimeMillis() + delayBeforeFirstBackup +
random.nextInt(FUZZ_MILLIS);
mAlarmManager.setRepeating(AlarmManager.RTC_WAKEUP, when,
BACKUP_INTERVAL + random.nextInt(FUZZ_MILLIS), mRunBackupIntent);
mNextBackupPass = when; mNextBackupPass = when;
} }