Remove render ahead from hwui

As HWUI uses vsync id to send buffers to SF, SF applies the right
amount of render ahead by latching the buffers at the configured time.

Test: launch an app and observe systrace
Bug: 178148035
Change-Id: Ifd3e1a2971aad0a085cb35d33e950194046aa634

1 files changed, 4 insertions, 45 deletions

diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 37a6ee71c4a6..65afcc3a2558 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -108,7 +108,6 @@ CanvasContext::CanvasContext(RenderThread& thread, bool translucent, RenderNode*
     rootRenderNode->makeRoot();
     mRenderNodes.emplace_back(rootRenderNode);
     mProfiler.setDensity(DeviceInfo::getDensity());
-    setRenderAheadDepth(Properties::defaultRenderAhead);
 }
 
 CanvasContext::~CanvasContext() {
@@ -157,24 +156,17 @@ static void setBufferCount(ANativeWindow* window) {
 void CanvasContext::setSurface(ANativeWindow* window, bool enableTimeout) {
     ATRACE_CALL();
 
-    if (mFixedRenderAhead) {
-        mRenderAheadCapacity = mRenderAheadDepth;
-    } else {
-        if (DeviceInfo::get()->getMaxRefreshRate() > 66.6f) {
-            mRenderAheadCapacity = 1;
-        } else {
-            mRenderAheadCapacity = 0;
-        }
-    }
-
     if (window) {
+        int extraBuffers = 0;
+        native_window_get_extra_buffer_count(window, &extraBuffers);
+
         mNativeSurface = std::make_unique<ReliableSurface>(window);
         mNativeSurface->init();
         if (enableTimeout) {
             // TODO: Fix error handling & re-shorten timeout
             ANativeWindow_setDequeueTimeout(window, 4000_ms);
         }
-        mNativeSurface->setExtraBufferCount(mRenderAheadCapacity);
+        mNativeSurface->setExtraBufferCount(extraBuffers);
     } else {
         mNativeSurface = nullptr;
     }
@@ -441,24 +433,6 @@ void CanvasContext::notifyFramePending() {
     mRenderThread.pushBackFrameCallback(this);
 }
 
-void CanvasContext::setPresentTime() {
-    int64_t presentTime = NATIVE_WINDOW_TIMESTAMP_AUTO;
-    int renderAhead = 0;
-    const auto frameIntervalNanos = mRenderThread.timeLord().frameIntervalNanos();
-    if (mFixedRenderAhead) {
-        renderAhead = std::min(mRenderAheadDepth, mRenderAheadCapacity);
-    } else if (frameIntervalNanos < 15_ms) {
-        renderAhead = std::min(1, static_cast<int>(mRenderAheadCapacity));
-    }
-
-    if (renderAhead) {
-        presentTime = mCurrentFrameInfo->get(FrameInfoIndex::Vsync) +
-                (frameIntervalNanos * (renderAhead + 1)) - DeviceInfo::get()->getAppOffset() +
-                (frameIntervalNanos / 2);
-    }
-    native_window_set_buffers_timestamp(mNativeSurface->getNativeWindow(), presentTime);
-}
-
 void CanvasContext::draw() {
     SkRect dirty;
     mDamageAccumulator.finish(&dirty);
@@ -478,8 +452,6 @@ void CanvasContext::draw() {
     mCurrentFrameInfo->markIssueDrawCommandsStart();
 
     Frame frame = mRenderPipeline->getFrame();
-    setPresentTime();
-
     SkRect windowDirty = computeDirtyRect(frame, &dirty);
 
     bool drew = mRenderPipeline->draw(frame, windowDirty, dirty, mLightGeometry, &mLayerUpdateQueue,
@@ -765,19 +737,6 @@ bool CanvasContext::surfaceRequiresRedraw() {
     return width != mLastFrameWidth || height != mLastFrameHeight;
 }
 
-void CanvasContext::setRenderAheadDepth(int renderAhead) {
-    if (renderAhead > 2 || renderAhead < -1 || mNativeSurface) {
-        return;
-    }
-    if (renderAhead == -1) {
-        mFixedRenderAhead = false;
-        mRenderAheadDepth = 0;
-    } else {
-        mFixedRenderAhead = true;
-        mRenderAheadDepth = static_cast<uint32_t>(renderAhead);
-    }
-}
-
 SkRect CanvasContext::computeDirtyRect(const Frame& frame, SkRect* dirty) {
     if (frame.width() != mLastFrameWidth || frame.height() != mLastFrameHeight) {
         // can't rely on prior content of window if viewport size changes