Commit adf5024a authored Mar 11, 2021 by Siarhei Vishniakou

Send metrics notification just before frame advances

Currently, it is possible to notify frame metrics observers that
registered to receive present time about the same frame twice.

This is wasteful, but also requires the metrics listener to guard
against duplicates. See https://b.corp.google.com/issues/169866723#comment23

To avoid this issue, only notify about metrics with present time just
before the frame is advanced to the next position. This ensures that we
are always notifying about the last frame that's about to go away.

Bug: 169866723
Test: added a crash to LatencyTracker for the case where we are notified
about non-existent record. The record disappears once it's complete. So
the first call was completing the record, and the second call was
causing a crash. Now, the crash is gone with this patch.

Change-Id: Ia247b4a0010b8ecb016ac66e44e211ec4f40bf8f

parent 603b4c4a

libs/hwui/renderthread/CanvasContext.cpp

+1 −2

Original line number	Diff line number	Diff line
		@@ -576,6 +576,7 @@ void CanvasContext::draw() {

		if (requireSwap) {
		if (mExpectSurfaceStats) {
		reportMetricsWithPresentTime();
		std::lock_guard lock(mLast4FrameInfosMutex);
		std::pair<FrameInfo*, int64_t>& next = mLast4FrameInfos.next();
		next.first = mCurrentFrameInfo;
		@@ -656,8 +657,6 @@ void CanvasContext::onSurfaceStatsAvailable(void* context, ASurfaceControl* cont
		}
		}

		instance->reportMetricsWithPresentTime();

		if (frameInfo != nullptr) {
		if (gpuCompleteTime == -1) {
		gpuCompleteTime = frameInfo->get(FrameInfoIndex::SwapBuffersCompleted);