4 files changed, 22 insertions, 15 deletions

diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index 38cb4cd..3e4e965 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -40,7 +40,7 @@ namespace renderthread {
 static const size_t EVENT_BUFFER_SIZE = 100;
 
 // Slight delay to give the UI time to push us a new frame before we replay
-static const int DISPATCH_FRAME_CALLBACKS_DELAY = 4;
+static const nsecs_t DISPATCH_FRAME_CALLBACKS_DELAY = milliseconds_to_nanoseconds(4);
 
 TaskQueue::TaskQueue() : mHead(0), mTail(0) {}
 
@@ -209,16 +209,16 @@ static nsecs_t latestVsyncEvent(DisplayEventReceiver* receiver) {
     return latest;
 }
 
-void RenderThread::drainDisplayEventQueue(bool skipCallbacks) {
+void RenderThread::drainDisplayEventQueue() {
     ATRACE_CALL();
     nsecs_t vsyncEvent = latestVsyncEvent(mDisplayEventReceiver);
     if (vsyncEvent > 0) {
         mVsyncRequested = false;
-        mTimeLord.vsyncReceived(vsyncEvent);
-        if (!skipCallbacks && !mFrameCallbackTaskPending) {
+        if (mTimeLord.vsyncReceived(vsyncEvent) && !mFrameCallbackTaskPending) {
             ATRACE_NAME("queue mFrameCallbackTask");
             mFrameCallbackTaskPending = true;
-            queueDelayed(mFrameCallbackTask, DISPATCH_FRAME_CALLBACKS_DELAY);
+            nsecs_t runAt = (vsyncEvent + DISPATCH_FRAME_CALLBACKS_DELAY);
+            queueAt(mFrameCallbackTask, runAt);
         }
     }
 }
@@ -230,8 +230,13 @@ void RenderThread::dispatchFrameCallbacks() {
     std::set<IFrameCallback*> callbacks;
     mFrameCallbacks.swap(callbacks);
 
-    for (std::set<IFrameCallback*>::iterator it = callbacks.begin(); it != callbacks.end(); it++) {
-        (*it)->doFrame();
+    if (callbacks.size()) {
+        // Assume one of them will probably animate again so preemptively
+        // request the next vsync in case it occurs mid-frame
+        requestVsync();
+        for (std::set<IFrameCallback*>::iterator it = callbacks.begin(); it != callbacks.end(); it++) {
+            (*it)->doFrame();
+        }
     }
 }
 
@@ -273,7 +278,7 @@ bool RenderThread::threadLoop() {
         }
 
         if (mPendingRegistrationFrameCallbacks.size() && !mFrameCallbackTaskPending) {
-            drainDisplayEventQueue(true);
+            drainDisplayEventQueue();
             mFrameCallbacks.insert(
                     mPendingRegistrationFrameCallbacks.begin(), mPendingRegistrationFrameCallbacks.end());
             mPendingRegistrationFrameCallbacks.clear();
@@ -299,9 +304,8 @@ void RenderThread::queueAtFront(RenderTask* task) {
     mLooper->wake();
 }
 
-void RenderThread::queueDelayed(RenderTask* task, int delayMs) {
-    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
-    task->mRunAt = now + milliseconds_to_nanoseconds(delayMs);
+void RenderThread::queueAt(RenderTask* task, nsecs_t runAtNs) {
+    task->mRunAt = runAtNs;
     queue(task);
 }
 
diff --git a/libs/hwui/renderthread/RenderThread.h b/libs/hwui/renderthread/RenderThread.h
index 4126d02..99c2e15 100644
--- a/libs/hwui/renderthread/RenderThread.h
+++ b/libs/hwui/renderthread/RenderThread.h
@@ -75,7 +75,7 @@ public:
     // and will delete them after they are run
     ANDROID_API void queue(RenderTask* task);
     ANDROID_API void queueAtFront(RenderTask* task);
-    void queueDelayed(RenderTask* task, int delayMs);
+    void queueAt(RenderTask* task, nsecs_t runAtNs);
     void remove(RenderTask* task);
 
     // Mimics android.view.Choreographer
@@ -103,7 +103,7 @@ private:
     void initThreadLocals();
     void initializeDisplayEventReceiver();
     static int displayEventReceiverCallback(int fd, int events, void* data);
-    void drainDisplayEventQueue(bool skipCallbacks = false);
+    void drainDisplayEventQueue();
     void dispatchFrameCallbacks();
     void requestVsync();
 
diff --git a/libs/hwui/renderthread/TimeLord.cpp b/libs/hwui/renderthread/TimeLord.cpp
index 9bd4eae..f187493 100644
--- a/libs/hwui/renderthread/TimeLord.cpp
+++ b/libs/hwui/renderthread/TimeLord.cpp
@@ -24,10 +24,12 @@ TimeLord::TimeLord()
         , mFrameTimeNanos(0) {
 }
 
-void TimeLord::vsyncReceived(nsecs_t vsync) {
+bool TimeLord::vsyncReceived(nsecs_t vsync) {
     if (vsync > mFrameTimeNanos) {
         mFrameTimeNanos = vsync;
+        return true;
     }
+    return false;
 }
 
 nsecs_t TimeLord::computeFrameTimeMs() {
diff --git a/libs/hwui/renderthread/TimeLord.h b/libs/hwui/renderthread/TimeLord.h
index 8b0372c..7c155d2 100644
--- a/libs/hwui/renderthread/TimeLord.h
+++ b/libs/hwui/renderthread/TimeLord.h
@@ -29,7 +29,8 @@ class RenderThread;
 class TimeLord {
 public:
     void setFrameInterval(nsecs_t intervalNanos) { mFrameIntervalNanos = intervalNanos; }
-    void vsyncReceived(nsecs_t vsync);
+    // returns true if the vsync is newer, false if it was rejected for staleness
+    bool vsyncReceived(nsecs_t vsync);
     nsecs_t computeFrameTimeMs();
 
 private: