commit 0f861867c609205d23cdfb655e2a068841f87266
author Yao Chen <yaochen@google.com> Wed Mar 27 11:51:15 2019 -0700
committer Yao Chen <yaochen@google.com> Thu Mar 28 14:44:37 2019 -0700
tree c068a21152f647518a22bd7138c575ad3041845d
parent cd62e4421040bdbf363372e78c288f41077b79ed

Make StatsLog drop less.

+ Create a thread-safe LogEventQueue to buffer log events.

+ The socket listner thread will read from socket and write to the buffer as quickly as possible
  to minimize the data loss in socket.

+ All pushed data is fetched from the the buffer and processed in a dedicated thread. After an
  event is fetched from the queue, we no longer block the socket listener thread.

+ Report event queue stats via statsdstats, including the min and max queue event history span in
  the queue (to understand how slow statsd can be and how fast the events can be)

Bug: 119031518
Test: unit tests added in statsd_test

Change-Id: I6b65ed9a678935b2e24302ba4b36e69c157adde4

cmds/statsd/src/StatsService.h

diff --git a/cmds/statsd/src/StatsService.h b/cmds/statsd/src/StatsService.h
index d24565a..cbe5b48 100644
--- a/cmds/statsd/src/StatsService.h
+++ b/cmds/statsd/src/StatsService.h
@@ -22,7 +22,7 @@
 #include "anomaly/AlarmMonitor.h"
 #include "config/ConfigManager.h"
 #include "external/StatsPullerManager.h"
-#include "logd/LogListener.h"
+#include "logd/LogEventQueue.h"
 #include "packages/UidMap.h"
 #include "shell/ShellSubscriber.h"
 #include "statscompanion_util.h"
@@ -52,11 +52,10 @@
 using android::hardware::Return;
 
 class StatsService : public BnStatsManager,
-                     public LogListener,
                      public IStats,
                      public IBinder::DeathRecipient {
 public:
-    StatsService(const sp<Looper>& handlerLooper);
+    StatsService(const sp<Looper>& handlerLooper, std::shared_ptr<LogEventQueue> queue);
     virtual ~StatsService();
 
     /** The anomaly alarm registered with AlarmManager won't be updated by less than this. */
@@ -92,7 +91,7 @@
     void Terminate();
 
     /**
-     * Called by LogReader when there's a log event to process.
+     * Test ONLY interface. In real world, StatsService reads from LogEventQueue.
      */
     virtual void OnLogEvent(LogEvent* event);
 
@@ -278,6 +277,9 @@
      */
     void print_cmd_help(int out);
 
+    /* Runs on its dedicated thread to process pushed stats event from socket. */
+    void readLogs();
+
     /**
      * Trigger a broadcast.
      */
@@ -410,6 +412,8 @@
 
     sp<ShellSubscriber> mShellSubscriber;
 
+    std::shared_ptr<LogEventQueue> mEventQueue;
+
     FRIEND_TEST(StatsServiceTest, TestAddConfig_simple);
     FRIEND_TEST(StatsServiceTest, TestAddConfig_empty);
     FRIEND_TEST(StatsServiceTest, TestAddConfig_invalid);