commit 5b7855f224cc048fe8c765ad760bca6fd77ae89f
author Alex Careja <alexcareja@google.com> Wed Sep 27 11:11:22 2023 +0000
committer Alex Careja <alexcareja@google.com> Fri Sep 29 14:28:07 2023 +0000
tree c70ec59697455ce6aae14e6717a7a88ac9b107f1
parent 102d39dbad6c568fc4daa17493b53380dcb8f0a0

Remove contention from Render Engine early return

An early return optimization path to skip post render cleanup in some
cases was resulting in lock contention so remove it and replace it with
an atomic boolean.

Bug: 273708680
Test: boot device, observe boot animation is smooth
Change-Id: Idd989a2e91a8ef1b71aef4e1c439eb0576511c79

libs/renderengine/tests/RenderEngineThreadedTest.cpp

diff --git a/libs/renderengine/tests/RenderEngineThreadedTest.cpp b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
index 475dc15..7289fe7 100644
--- a/libs/renderengine/tests/RenderEngineThreadedTest.cpp
+++ b/libs/renderengine/tests/RenderEngineThreadedTest.cpp
@@ -98,7 +98,6 @@
 }
 
 TEST_F(RenderEngineThreadedTest, PostRenderCleanup_skipped) {
-    EXPECT_CALL(*mRenderEngine, canSkipPostRenderCleanup()).WillOnce(Return(true));
     EXPECT_CALL(*mRenderEngine, cleanupPostRender()).Times(0);
     mThreadedRE->cleanupPostRender();
 
@@ -107,8 +106,25 @@
 }
 
 TEST_F(RenderEngineThreadedTest, PostRenderCleanup_notSkipped) {
-    EXPECT_CALL(*mRenderEngine, canSkipPostRenderCleanup()).WillOnce(Return(false));
+    renderengine::DisplaySettings settings;
+    std::vector<renderengine::LayerSettings> layers;
+    std::shared_ptr<renderengine::ExternalTexture> buffer = std::make_shared<
+            renderengine::impl::
+                    ExternalTexture>(sp<GraphicBuffer>::make(), *mRenderEngine,
+                                     renderengine::impl::ExternalTexture::Usage::READABLE |
+                                             renderengine::impl::ExternalTexture::Usage::WRITEABLE);
+    base::unique_fd bufferFence;
+
+    EXPECT_CALL(*mRenderEngine, useProtectedContext(false));
+    EXPECT_CALL(*mRenderEngine, drawLayersInternal)
+        .WillOnce([&](const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+                          const renderengine::DisplaySettings&,
+                          const std::vector<renderengine::LayerSettings>&,
+                          const std::shared_ptr<renderengine::ExternalTexture>&,
+                          base::unique_fd&&) { resultPromise->set_value(Fence::NO_FENCE); });
     EXPECT_CALL(*mRenderEngine, cleanupPostRender()).WillOnce(Return());
+    ftl::Future<FenceResult> future =
+            mThreadedRE->drawLayers(settings, layers, buffer, std::move(bufferFence));
     mThreadedRE->cleanupPostRender();
 
     // call ANY synchronous function to ensure that cleanupPostRender has completed.

libs/renderengine/threaded/RenderEngineThreaded.cpp

diff --git a/libs/renderengine/threaded/RenderEngineThreaded.cpp b/libs/renderengine/threaded/RenderEngineThreaded.cpp
index 2cb66cb..786a6fe 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.cpp
+++ b/libs/renderengine/threaded/RenderEngineThreaded.cpp
@@ -231,13 +231,13 @@
             ATRACE_NAME("REThreaded::cleanupPostRender");
             instance.cleanupPostRender();
         });
+        mNeedsPostRenderCleanup = false;
     }
     mCondition.notify_one();
 }
 
 bool RenderEngineThreaded::canSkipPostRenderCleanup() const {
-    waitUntilInitialized();
-    return mRenderEngine->canSkipPostRenderCleanup();
+    return !mNeedsPostRenderCleanup;
 }
 
 void RenderEngineThreaded::drawLayersInternal(
@@ -257,6 +257,7 @@
     int fd = bufferFence.release();
     {
         std::lock_guard lock(mThreadMutex);
+        mNeedsPostRenderCleanup = true;
         mFunctionCalls.push(
                 [resultPromise, display, layers, buffer, fd](renderengine::RenderEngine& instance) {
                     ATRACE_NAME("REThreaded::drawLayers");

libs/renderengine/threaded/RenderEngineThreaded.h

diff --git a/libs/renderengine/threaded/RenderEngineThreaded.h b/libs/renderengine/threaded/RenderEngineThreaded.h
index 43ec011..1093f5f 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.h
+++ b/libs/renderengine/threaded/RenderEngineThreaded.h
@@ -89,6 +89,7 @@
     mutable std::mutex mThreadMutex;
     std::thread mThread GUARDED_BY(mThreadMutex);
     std::atomic<bool> mRunning = true;
+    std::atomic<bool> mNeedsPostRenderCleanup = false;
 
     using Work = std::function<void(renderengine::RenderEngine&)>;
     mutable std::queue<Work> mFunctionCalls GUARDED_BY(mThreadMutex);