From 62a9ff67184381c1543e8851cd34424183afac7a Mon Sep 17 00:00:00 2001
From: Michael Wachenschwanz <mwachens@google.com>
Date: Mon, 24 May 2021 21:54:06 -0700
Subject: [PATCH] Move RPM stats collection out of BatteryStatsImpl.mLock

Querying RPM stats on device with a large number of StateResidency info
can take a long time. Move the query to outside of the BatteryStats
lock to reduce the chance of lock contention.

Bug: 185970842
Test: atest android.cts.statsd.validation.ValidationTests#testPartialWakelock

Change-Id: I1c69b3f9c071e5d758cf4b22855c4b0ec221a5cf
---
 .../android/internal/os/BatteryStatsImpl.java | 27 ++++++++++++++-----
 .../server/am/BatteryExternalStatsWorker.java |  3 +++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/core/java/com/android/internal/os/BatteryStatsImpl.java b/core/java/com/android/internal/os/BatteryStatsImpl.java
index be059a1e195ba..a68a007dad568 100644
--- a/core/java/com/android/internal/os/BatteryStatsImpl.java
+++ b/core/java/com/android/internal/os/BatteryStatsImpl.java
@@ -275,7 +275,7 @@ public class BatteryStatsImpl extends BatteryStats {
     private int mNumAllUidCpuTimeReads;
 
     /** Container for Resource Power Manager stats. Updated by updateRpmStatsLocked. */
-    private final RpmStats mTmpRpmStats = new RpmStats();
+    private RpmStats mTmpRpmStats = null;
     /** The soonest the RPM stats can be updated after it was last updated. */
     private static final long RPM_STATS_UPDATE_FREQ_MS = 1000;
     /** Last time that RPM stats were updated by updateRpmStatsLocked. */
@@ -12387,19 +12387,34 @@ public class BatteryStatsImpl extends BatteryStats {
 
         mLastBluetoothActivityInfo.set(info);
     }
-
     /**
-     * Read and record Resource Power Manager (RPM) state and voter times.
+     * Read Resource Power Manager (RPM) state and voter times.
      * If RPM stats were fetched more recently than RPM_STATS_UPDATE_FREQ_MS ago, uses the old data
      * instead of fetching it anew.
+     *
+     * Note: This should be called without synchronizing this BatteryStatsImpl object
      */
-    public void updateRpmStatsLocked(long elapsedRealtimeUs) {
+    public void fillLowPowerStats() {
         if (mPlatformIdleStateCallback == null) return;
+
+        RpmStats rpmStats = new RpmStats();
         long now = SystemClock.elapsedRealtime();
         if (now - mLastRpmStatsUpdateTimeMs >= RPM_STATS_UPDATE_FREQ_MS) {
-            mPlatformIdleStateCallback.fillLowPowerStats(mTmpRpmStats);
-            mLastRpmStatsUpdateTimeMs = now;
+            mPlatformIdleStateCallback.fillLowPowerStats(rpmStats);
+            synchronized (this) {
+                mTmpRpmStats = rpmStats;
+                mLastRpmStatsUpdateTimeMs = now;
+            }
         }
+    }
+
+    /**
+     * Record Resource Power Manager (RPM) state and voter times.
+     * TODO(b/185252376): Remove this logging. PowerStatsService logs the same data more
+     * efficiently.
+     */
+    public void updateRpmStatsLocked(long elapsedRealtimeUs) {
+        if (mTmpRpmStats == null) return;
 
         for (Map.Entry<String, RpmStats.PowerStatePlatformSleepState> pstate
                 : mTmpRpmStats.mPlatformLowPowerStats.entrySet()) {
diff --git a/services/core/java/com/android/server/am/BatteryExternalStatsWorker.java b/services/core/java/com/android/server/am/BatteryExternalStatsWorker.java
index 406e8665735d1..67dfb8051f93c 100644
--- a/services/core/java/com/android/server/am/BatteryExternalStatsWorker.java
+++ b/services/core/java/com/android/server/am/BatteryExternalStatsWorker.java
@@ -579,6 +579,9 @@ class BatteryExternalStatsWorker implements BatteryStatsImpl.ExternalStatsSync {
             }
         }
 
+        // Collect the latest low power stats without holding the mStats lock.
+        mStats.fillLowPowerStats();
+
         final WifiActivityEnergyInfo wifiInfo = awaitControllerInfo(wifiReceiver);
         final BluetoothActivityEnergyInfo bluetoothInfo = awaitControllerInfo(bluetoothReceiver);
         ModemActivityInfo modemInfo = null;