Tweak RT-animator scheduling
Bug: 18226391
The issue occurs as a result of a dispatchFrame itself
taking longer than 12ms, the alloted budget. The result
is that a vsync request (which occured at the end) would
miss the vsync that occured 1ms prior to the end of the frame.
As a result it would end up waiting for the following vsync,
essentially dropping to 30fps even though 60 could have been
sustained.
Fix this with a few tweaks.
First, adjust the UI thread's delay bias from (now + 4ms) to
(vsync + 4ms), this prevents RT animators from slowly drifting
if the vsync occurs mid-task.
Second, request a vsync preemptively prior to running callbacks.
This way if any callbacks needs the next vsync and it takes
"too long", we will catch that vsync.
Finally, fix an issue where the display event queue was always
drained & rejected at the end of a task loop. Instead, drain
and reject all stale vsyncs. This still prevents the issue of
both UI thread & RT thread trying to drive 2 frames in a single
pulse, but also allows RT to notice that it missed a vsync
pulse it needed and that it should speed-up a bit in response
Change-Id: I9d6be037737e9283297898cac2e3563453e797cd
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 @@
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 @@
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 @@
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 @@
}
if (mPendingRegistrationFrameCallbacks.size() && !mFrameCallbackTaskPending) {
- drainDisplayEventQueue(true);
+ drainDisplayEventQueue();
mFrameCallbacks.insert(
mPendingRegistrationFrameCallbacks.begin(), mPendingRegistrationFrameCallbacks.end());
mPendingRegistrationFrameCallbacks.clear();
@@ -299,9 +304,8 @@
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);
}