From 0a8c58b06b2e78b6ee02963a98065e846fdd0857 Mon Sep 17 00:00:00 2001
From: Chalard Jean <jchalard@google.com>
Date: Wed, 22 Aug 2018 10:21:26 +0900
Subject: [PATCH] Delay global alerts by 1s for high thresholds

This is a cherry-pick of aosp/735725 with a minor conflict.

By skipping updates if an alert is already scheduled, this avoids firing
the global alert too often on devices with high transfer speeds and high
quota.

Test: with tethering watching videos. Also runtest frameworks-net
Bug: 117243748
Change-Id: Ia0ed76141dfb33546529786eb0118138ef3708c2
Merged-In: Ie0ba5c1d1a2139606e63fcfe46ec77a89accd8d9
Merged-In: Iaabb31586e9e747871a526dc7ebb7deeb65d8f83
---
 .../server/net/NetworkStatsService.java       | 33 ++++++++++++-------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java
index fec510f28a..9bf3874088 100644
--- a/services/core/java/com/android/server/net/NetworkStatsService.java
+++ b/services/core/java/com/android/server/net/NetworkStatsService.java
@@ -159,9 +159,11 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     static final boolean LOGD = Log.isLoggable(TAG, Log.DEBUG);
     static final boolean LOGV = Log.isLoggable(TAG, Log.VERBOSE);
 
+    // Perform polling and persist all (FLAG_PERSIST_ALL).
     private static final int MSG_PERFORM_POLL = 1;
     private static final int MSG_UPDATE_IFACES = 2;
-    private static final int MSG_REGISTER_GLOBAL_ALERT = 3;
+    // Perform polling, persist network, and register the global alert again.
+    private static final int MSG_PERFORM_POLL_REGISTER_ALERT = 3;
 
     /** Flags to control detail level of poll event. */
     private static final int FLAG_PERSIST_NETWORK = 0x1;
@@ -169,6 +171,14 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     private static final int FLAG_PERSIST_ALL = FLAG_PERSIST_NETWORK | FLAG_PERSIST_UID;
     private static final int FLAG_PERSIST_FORCE = 0x100;
 
+    /**
+     * When global alert quota is high, wait for this delay before processing each polling,
+     * and do not schedule further polls once there is already one queued.
+     * This avoids firing the global alert too often on devices with high transfer speeds and
+     * high quota.
+     */
+    private static final int PERFORM_POLL_DELAY_MS = 1000;
+
     private static final String TAG_NETSTATS_ERROR = "netstats_error";
 
     private final Context mContext;
@@ -916,7 +926,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         }
 
         // Create baseline stats
-        mHandler.sendMessage(mHandler.obtainMessage(MSG_PERFORM_POLL, FLAG_PERSIST_ALL));
+        mHandler.sendMessage(mHandler.obtainMessage(MSG_PERFORM_POLL));
 
         return normalizedRequest;
    }
@@ -1057,13 +1067,12 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
 
             if (LIMIT_GLOBAL_ALERT.equals(limitName)) {
-                // kick off background poll to collect network stats; UID stats
-                // are handled during normal polling interval.
-                final int flags = FLAG_PERSIST_NETWORK;
-                mHandler.obtainMessage(MSG_PERFORM_POLL, flags, 0).sendToTarget();
-
-                // re-arm global alert for next update
-                mHandler.obtainMessage(MSG_REGISTER_GLOBAL_ALERT).sendToTarget();
+                // kick off background poll to collect network stats unless there is already
+                // such a call pending; UID stats are handled during normal polling interval.
+                if (!mHandler.hasMessages(MSG_PERFORM_POLL_REGISTER_ALERT)) {
+                    mHandler.sendEmptyMessageDelayed(MSG_PERFORM_POLL_REGISTER_ALERT,
+                            PERFORM_POLL_DELAY_MS);
+                }
             }
         }
     };
@@ -1675,15 +1684,15 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         public boolean handleMessage(Message msg) {
             switch (msg.what) {
                 case MSG_PERFORM_POLL: {
-                    final int flags = msg.arg1;
-                    mService.performPoll(flags);
+                    mService.performPoll(FLAG_PERSIST_ALL);
                     return true;
                 }
                 case MSG_UPDATE_IFACES: {
                     mService.updateIfaces(null);
                     return true;
                 }
-                case MSG_REGISTER_GLOBAL_ALERT: {
+                case MSG_PERFORM_POLL_REGISTER_ALERT: {
+                    mService.performPoll(FLAG_PERSIST_NETWORK);
                     mService.registerGlobalAlert();
                     return true;
                 }