Adjust wifi idle times to fit in system time period
The battery stats time period calculation is done using a
different clock source compared to the wifi chip's on time calculation. So,
account for skews between the two by adjusting the idle time reported by
wifi chip to fit into the system time calculation.
BUG: 28628799
Change-Id: I3110c53317f3246e26fdc3731f7be0a3d9c8e229
TEST: Compiles & manual verification
diff --git a/services/core/java/com/android/server/am/BatteryStatsService.java b/services/core/java/com/android/server/am/BatteryStatsService.java
index 96934f0..b4df10f 100644
--- a/services/core/java/com/android/server/am/BatteryStatsService.java
+++ b/services/core/java/com/android/server/am/BatteryStatsService.java
@@ -1323,55 +1323,60 @@
delta.mTimestamp = latest.getTimeStamp();
delta.mStackState = latest.getStackState();
- // These times seem to be the most reliable.
- delta.mControllerTxTimeMs = latest.mControllerTxTimeMs - lastTxMs;
- delta.mControllerRxTimeMs = latest.mControllerRxTimeMs - lastRxMs;
+ final long txTimeMs = latest.mControllerTxTimeMs - lastTxMs;
+ final long rxTimeMs = latest.mControllerRxTimeMs - lastRxMs;
+ final long idleTimeMs = latest.mControllerIdleTimeMs - lastIdleMs;
- // WiFi calculates the idle time as a difference from the on time and the various
- // Rx + Tx times. There seems to be some missing time there because this sometimes
- // becomes negative. Just cap it at 0 and move on.
- // b/21613534
- delta.mControllerIdleTimeMs = Math.max(0, latest.mControllerIdleTimeMs - lastIdleMs);
- delta.mControllerEnergyUsed = Math.max(0, latest.mControllerEnergyUsed - lastEnergy);
-
- if (delta.mControllerTxTimeMs < 0 || delta.mControllerRxTimeMs < 0) {
+ if (txTimeMs < 0 || rxTimeMs < 0) {
// The stats were reset by the WiFi system (which is why our delta is negative).
// Returns the unaltered stats.
delta.mControllerEnergyUsed = latest.mControllerEnergyUsed;
delta.mControllerRxTimeMs = latest.mControllerRxTimeMs;
delta.mControllerTxTimeMs = latest.mControllerTxTimeMs;
delta.mControllerIdleTimeMs = latest.mControllerIdleTimeMs;
-
Slog.v(TAG, "WiFi energy data was reset, new WiFi energy data is " + delta);
- }
-
- // There is some accuracy error in reports so allow some slop in the results.
- final long SAMPLE_ERROR_MILLIS = 750;
- final long totalTimeMs = delta.mControllerIdleTimeMs + delta.mControllerRxTimeMs +
- delta.mControllerTxTimeMs;
- if (totalTimeMs > timePeriodMs + SAMPLE_ERROR_MILLIS) {
- StringBuilder sb = new StringBuilder();
- sb.append("Total time ");
- TimeUtils.formatDuration(totalTimeMs, sb);
- sb.append(" is longer than sample period ");
- TimeUtils.formatDuration(timePeriodMs, sb);
- sb.append(".\n");
- sb.append("Previous WiFi snapshot: ").append("idle=");
- TimeUtils.formatDuration(lastIdleMs, sb);
- sb.append(" rx=");
- TimeUtils.formatDuration(lastRxMs, sb);
- sb.append(" tx=");
- TimeUtils.formatDuration(lastTxMs, sb);
- sb.append(" e=").append(lastEnergy);
- sb.append("\n");
- sb.append("Current WiFi snapshot: ").append("idle=");
- TimeUtils.formatDuration(latest.mControllerIdleTimeMs, sb);
- sb.append(" rx=");
- TimeUtils.formatDuration(latest.mControllerRxTimeMs, sb);
- sb.append(" tx=");
- TimeUtils.formatDuration(latest.mControllerTxTimeMs, sb);
- sb.append(" e=").append(latest.mControllerEnergyUsed);
- Slog.wtf(TAG, sb.toString());
+ } else {
+ final long totalActiveTimeMs = txTimeMs + rxTimeMs;
+ long maxExpectedIdleTimeMs;
+ // Active time can never be greater than the total time, the stats received seem
+ // to be corrupt.
+ if (totalActiveTimeMs > timePeriodMs) {
+ maxExpectedIdleTimeMs = timePeriodMs;
+ StringBuilder sb = new StringBuilder();
+ sb.append("Total Active time ");
+ TimeUtils.formatDuration(totalActiveTimeMs, sb);
+ sb.append(" is longer than sample period ");
+ TimeUtils.formatDuration(timePeriodMs, sb);
+ sb.append(".\n");
+ sb.append("Previous WiFi snapshot: ").append("idle=");
+ TimeUtils.formatDuration(lastIdleMs, sb);
+ sb.append(" rx=");
+ TimeUtils.formatDuration(lastRxMs, sb);
+ sb.append(" tx=");
+ TimeUtils.formatDuration(lastTxMs, sb);
+ sb.append(" e=").append(lastEnergy);
+ sb.append("\n");
+ sb.append("Current WiFi snapshot: ").append("idle=");
+ TimeUtils.formatDuration(latest.mControllerIdleTimeMs, sb);
+ sb.append(" rx=");
+ TimeUtils.formatDuration(latest.mControllerRxTimeMs, sb);
+ sb.append(" tx=");
+ TimeUtils.formatDuration(latest.mControllerTxTimeMs, sb);
+ sb.append(" e=").append(latest.mControllerEnergyUsed);
+ Slog.wtf(TAG, sb.toString());
+ } else {
+ maxExpectedIdleTimeMs = timePeriodMs - totalActiveTimeMs;
+ }
+ // These times seem to be the most reliable.
+ delta.mControllerTxTimeMs = txTimeMs;
+ delta.mControllerRxTimeMs = rxTimeMs;
+ // WiFi calculates the idle time as a difference from the on time and the various
+ // Rx + Tx times. There seems to be some missing time there because this sometimes
+ // becomes negative. Just cap it at 0 and ensure that it is less than the expected idle
+ // time from the difference in timestamps.
+ // b/21613534
+ delta.mControllerIdleTimeMs = Math.min(maxExpectedIdleTimeMs, Math.max(0, idleTimeMs));
+ delta.mControllerEnergyUsed = Math.max(0, latest.mControllerEnergyUsed - lastEnergy);
}
mLastInfo = latest;
