commit 56ae42613c91f6a6fb0dc3f626daa24666fd18c2
author Aravind Akella <aakella@google.com> Thu Jul 10 16:01:10 2014 -0700
committer Aravind Akella <aakella@google.com> Thu Jul 24 17:23:01 2014 -0700
tree bc892f5f3314eaa0d2d184162774fe8d215cc0c3
parent 2cbba477bea136698944ece498115dbddd7bb659

SensorService performance improvements.

  i) Send ack for wake_up sensors on the socket connection instead of using Binder RPC.
  ii) Cache events per connection in case there are write failures. Compute cache size
      from FIFO counts of sensors.
 iii) Send FlushCompleteEvent only for apps that explicitly called flush().

Change-Id: I018969736b7794b1b930529586f2294a03ee8667

libs/gui/BitTube.cpp

diff --git a/libs/gui/BitTube.cpp b/libs/gui/BitTube.cpp
index 0282834..3ed1f37 100644
--- a/libs/gui/BitTube.cpp
+++ b/libs/gui/BitTube.cpp
@@ -99,6 +99,11 @@
     return mReceiveFd;
 }
 
+int BitTube::getSendFd() const
+{
+    return mSendFd;
+}
+
 ssize_t BitTube::write(void const* vaddr, size_t size)
 {
     ssize_t err, len;

libs/gui/ISensorEventConnection.cpp

diff --git a/libs/gui/ISensorEventConnection.cpp b/libs/gui/ISensorEventConnection.cpp
index 8f88141..28fcb53 100644
--- a/libs/gui/ISensorEventConnection.cpp
+++ b/libs/gui/ISensorEventConnection.cpp
@@ -34,8 +34,7 @@
     GET_SENSOR_CHANNEL = IBinder::FIRST_CALL_TRANSACTION,
     ENABLE_DISABLE,
     SET_EVENT_RATE,
-    FLUSH_SENSOR,
-    DECREASE_WAKE_LOCK_REFCOUNT
+    FLUSH_SENSOR
 };
 
 class BpSensorEventConnection : public BpInterface<ISensorEventConnection>
@@ -84,13 +83,6 @@
         remote()->transact(FLUSH_SENSOR, data, &reply);
         return reply.readInt32();
     }
-
-    virtual void decreaseWakeLockRefCount() {
-        Parcel data, reply;
-        data.writeInterfaceToken(ISensorEventConnection::getInterfaceDescriptor());
-        remote()->transact(DECREASE_WAKE_LOCK_REFCOUNT, data, &reply, IBinder::FLAG_ONEWAY);
-        return;
-    }
 };
 
 IMPLEMENT_META_INTERFACE(SensorEventConnection, "android.gui.SensorEventConnection");
@@ -133,11 +125,6 @@
             reply->writeInt32(result);
             return NO_ERROR;
         } break;
-        case DECREASE_WAKE_LOCK_REFCOUNT: {
-            CHECK_INTERFACE(ISensorEventConnection, data, reply);
-            decreaseWakeLockRefCount();
-            return NO_ERROR;
-        } break;
     }
     return BBinder::onTransact(code, data, reply, flags);
 }

libs/gui/SensorEventQueue.cpp

diff --git a/libs/gui/SensorEventQueue.cpp b/libs/gui/SensorEventQueue.cpp
index c2eaf4e..842502d 100644
--- a/libs/gui/SensorEventQueue.cpp
+++ b/libs/gui/SensorEventQueue.cpp
@@ -18,6 +18,7 @@
 
 #include <stdint.h>
 #include <sys/types.h>
+#include <sys/socket.h>
 
 #include <utils/Errors.h>
 #include <utils/RefBase.h>
@@ -147,7 +148,14 @@
 void SensorEventQueue::sendAck(const ASensorEvent* events, int count) {
     for (int i = 0; i < count; ++i) {
         if (events[i].flags & WAKE_UP_SENSOR_EVENT_NEEDS_ACK) {
-            mSensorEventConnection->decreaseWakeLockRefCount();
+            // Send just a byte of data to acknowledge for the wake up sensor events
+            // received
+            char buf = '1';
+            ssize_t size = ::send(mSensorChannel->getFd(), &buf, sizeof(buf),
+                                             MSG_DONTWAIT | MSG_NOSIGNAL);
+            if (size < 0) {
+                ALOGE("sendAck failure %d", size);
+            }
         }
     }
     return;