Merge "Use delta reads for per uid traffic stats" am: 39de2905a5

am: 03074c729f

Change-Id: Ibc1e7d1b6be2915d4000cda2b7a9141ac387f7f0

core/java/com/android/internal/net/NetworkStatsFactory.java

@@ -64,6 +64,9 @@ public class NetworkStatsFactory {
 
     private boolean mUseBpfStats;
 
+    // A persistent Snapshot since device start for eBPF stats
+    private final NetworkStats mPersistSnapshot;
+
     // TODO: only do adjustments in NetworkStatsService and remove this.
     /**
      * (Stacked interface) -> (base interface) association for all connected ifaces since boot.
@@ -135,6 +138,7 @@ public class NetworkStatsFactory {
         mStatsXtIfaceFmt = new File(procRoot, "net/xt_qtaguid/iface_stat_fmt");
         mStatsXtUid = new File(procRoot, "net/xt_qtaguid/stats");
         mUseBpfStats = useBpfStats;
+        mPersistSnapshot = new NetworkStats(SystemClock.elapsedRealtime(), -1);
     }
 
     public NetworkStats readBpfNetworkStatsDev() throws IOException {
@@ -268,6 +272,7 @@ public class NetworkStatsFactory {
         return stats;
     }
 
+    // TODO: delete the lastStats parameter
     private NetworkStats readNetworkStatsDetailInternal(int limitUid, String[] limitIfaces,
             int limitTag, NetworkStats lastStats) throws IOException {
         if (USE_NATIVE_PARSING) {
@@ -278,6 +283,17 @@ public class NetworkStatsFactory {
             } else {
                 stats = new NetworkStats(SystemClock.elapsedRealtime(), -1);
             }
+            if (mUseBpfStats) {
+                if (nativeReadNetworkStatsDetail(stats, mStatsXtUid.getAbsolutePath(), UID_ALL,
+                        null, TAG_ALL, mUseBpfStats) != 0) {
+                    throw new IOException("Failed to parse network stats");
+                }
+                mPersistSnapshot.setElapsedRealtime(stats.getElapsedRealtime());
+                mPersistSnapshot.combineAllValues(stats);
+                NetworkStats result = mPersistSnapshot.clone();
+                result.filter(limitUid, limitIfaces, limitTag);
+                return result;
+            } else {
                 if (nativeReadNetworkStatsDetail(stats, mStatsXtUid.getAbsolutePath(), limitUid,
                         limitIfaces, limitTag, mUseBpfStats) != 0) {
                     throw new IOException("Failed to parse network stats");
@@ -288,6 +304,7 @@ public class NetworkStatsFactory {
                     assertEquals(javaStats, stats);
                 }
                 return stats;
+            }
         } else {
             return javaReadNetworkStatsDetail(mStatsXtUid, limitUid, limitIfaces, limitTag);
         }