Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b080660d authored by Jeff Brown's avatar Jeff Brown
Browse files

Fix a possible starvation issue related to vsync. 

This makes a noticeable improvement in cases where applications
post messages that need to be processed between animation frames.

Bug: 6418353
Change-Id: If225742e37aeaf3f0ca9710f9bf43dbb03bcde12
parent d44a1686

core/java/android/view/Choreographer.java

+20 −2
Original line number Diff line number Diff line
@@ -491,14 +491,32 @@ public final class Choreographer { 
        }

    }



    private final class FrameDisplayEventReceiver extends DisplayEventReceiver {

    private final class FrameDisplayEventReceiver extends DisplayEventReceiver

            implements Runnable {

        private long mTimestampNanos;

        private int mFrame;



        public FrameDisplayEventReceiver(Looper looper) {

            super(looper);

        }



        @Override

        public void onVsync(long timestampNanos, int frame) {

            doFrame(timestampNanos, frame);

            // Post the vsync event to the Handler.

            // The idea is to prevent incoming vsync events from completely starving

            // the message queue.  If there are no messages in the queue with timestamps

            // earlier than the frame time, then the vsync event will be processed immediately.

            // Otherwise, messages that predate the vsync event will be handled first.

            mTimestampNanos = timestampNanos;

            mFrame = frame;

            Message msg = Message.obtain(mHandler, this);

            msg.setAsynchronous(true);

            mHandler.sendMessageAtTime(msg, timestampNanos / NANOS_PER_MS);

        }



        @Override

        public void run() {

            doFrame(mTimestampNanos, mFrame);

        }

    }