Add output fb cache to renderengine

On some devices this can shave off multiple milliseconds.

Bug: 123107664
Test: manual tests, systrace
Change-Id: If29b1753f899fec03852fb1ddaaa1a245f68424b
diff --git a/libs/renderengine/RenderEngine.cpp b/libs/renderengine/RenderEngine.cpp
index 6dd7283..166c267 100644
--- a/libs/renderengine/RenderEngine.cpp
+++ b/libs/renderengine/RenderEngine.cpp
@@ -24,15 +24,16 @@
 namespace android {
 namespace renderengine {
 
-std::unique_ptr<impl::RenderEngine> RenderEngine::create(int hwcFormat, uint32_t featureFlags) {
+std::unique_ptr<impl::RenderEngine> RenderEngine::create(int hwcFormat, uint32_t featureFlags,
+                                                         uint32_t imageCacheSize) {
     char prop[PROPERTY_VALUE_MAX];
     property_get(PROPERTY_DEBUG_RENDERENGINE_BACKEND, prop, "gles");
     if (strcmp(prop, "gles") == 0) {
         ALOGD("RenderEngine GLES Backend");
-        return renderengine::gl::GLESRenderEngine::create(hwcFormat, featureFlags);
+        return renderengine::gl::GLESRenderEngine::create(hwcFormat, featureFlags, imageCacheSize);
     }
     ALOGE("UNKNOWN BackendType: %s, create GLES RenderEngine.", prop);
-    return renderengine::gl::GLESRenderEngine::create(hwcFormat, featureFlags);
+    return renderengine::gl::GLESRenderEngine::create(hwcFormat, featureFlags, imageCacheSize);
 }
 
 RenderEngine::~RenderEngine() = default;
diff --git a/libs/renderengine/gl/GLESRenderEngine.cpp b/libs/renderengine/gl/GLESRenderEngine.cpp
index e7ff9ab..5d0aa1e 100644
--- a/libs/renderengine/gl/GLESRenderEngine.cpp
+++ b/libs/renderengine/gl/GLESRenderEngine.cpp
@@ -37,6 +37,7 @@
 #include <sync/sync.h>
 #include <ui/ColorSpace.h>
 #include <ui/DebugUtils.h>
+#include <ui/GraphicBuffer.h>
 #include <ui/Rect.h>
 #include <ui/Region.h>
 #include <utils/KeyedVector.h>
@@ -225,7 +226,8 @@
     return err;
 }
 
-std::unique_ptr<GLESRenderEngine> GLESRenderEngine::create(int hwcFormat, uint32_t featureFlags) {
+std::unique_ptr<GLESRenderEngine> GLESRenderEngine::create(int hwcFormat, uint32_t featureFlags,
+                                                           uint32_t imageCacheSize) {
     // initialize EGL for the default display
     EGLDisplay display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
     if (!eglInitialize(display, nullptr, nullptr)) {
@@ -295,7 +297,8 @@
         case GLES_VERSION_2_0:
         case GLES_VERSION_3_0:
             engine = std::make_unique<GLESRenderEngine>(featureFlags, display, config, ctxt, dummy,
-                                                        protectedContext, protectedDummy);
+                                                        protectedContext, protectedDummy,
+                                                        imageCacheSize);
             break;
     }
 
@@ -351,7 +354,7 @@
 
 GLESRenderEngine::GLESRenderEngine(uint32_t featureFlags, EGLDisplay display, EGLConfig config,
                                    EGLContext ctxt, EGLSurface dummy, EGLContext protectedContext,
-                                   EGLSurface protectedDummy)
+                                   EGLSurface protectedDummy, uint32_t imageCacheSize)
       : renderengine::impl::RenderEngine(featureFlags),
         mEGLDisplay(display),
         mEGLConfig(config),
@@ -361,6 +364,7 @@
         mProtectedDummySurface(protectedDummy),
         mVpWidth(0),
         mVpHeight(0),
+        mFramebufferImageCacheSize(imageCacheSize),
         mUseColorManagement(featureFlags & USE_COLOR_MANAGEMENT) {
     glGetIntegerv(GL_MAX_TEXTURE_SIZE, &mMaxTextureSize);
     glGetIntegerv(GL_MAX_VIEWPORT_DIMS, mMaxViewportDims);
@@ -428,6 +432,10 @@
 }
 
 GLESRenderEngine::~GLESRenderEngine() {
+    for (const auto& image : mFramebufferImageCache) {
+        eglDestroyImageKHR(mEGLDisplay, image.second);
+    }
+    mFramebufferImageCache.clear();
     eglMakeCurrent(mEGLDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
     eglTerminate(mEGLDisplay);
 }
@@ -785,6 +793,32 @@
     }
     return success;
 }
+EGLImageKHR GLESRenderEngine::createFramebufferImageIfNeeded(ANativeWindowBuffer* nativeBuffer,
+                                                             bool isProtected) {
+    sp<GraphicBuffer> graphicBuffer = GraphicBuffer::from(nativeBuffer);
+    uint32_t bufferId = graphicBuffer->getId();
+    for (const auto& image : mFramebufferImageCache) {
+        if (image.first == bufferId) {
+            return image.second;
+        }
+    }
+    EGLint attributes[] = {
+            isProtected ? EGL_PROTECTED_CONTENT_EXT : EGL_NONE,
+            isProtected ? EGL_TRUE : EGL_NONE,
+            EGL_NONE,
+    };
+    EGLImageKHR image = eglCreateImageKHR(mEGLDisplay, EGL_NO_CONTEXT, EGL_NATIVE_BUFFER_ANDROID,
+                                          nativeBuffer, attributes);
+    if (image != EGL_NO_IMAGE_KHR) {
+        if (mFramebufferImageCache.size() >= mFramebufferImageCacheSize) {
+            EGLImageKHR expired = mFramebufferImageCache.front().second;
+            mFramebufferImageCache.pop_front();
+            eglDestroyImageKHR(mEGLDisplay, expired);
+        }
+        mFramebufferImageCache.push_back({bufferId, image});
+    }
+    return image;
+}
 
 status_t GLESRenderEngine::drawLayers(const DisplaySettings& display,
                                       const std::vector<LayerSettings>& layers,
diff --git a/libs/renderengine/gl/GLESRenderEngine.h b/libs/renderengine/gl/GLESRenderEngine.h
index a86b4f5..e37c91d 100644
--- a/libs/renderengine/gl/GLESRenderEngine.h
+++ b/libs/renderengine/gl/GLESRenderEngine.h
@@ -21,16 +21,17 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <condition_variable>
+#include <deque>
 #include <mutex>
 #include <queue>
 #include <thread>
+#include <unordered_map>
 
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 #include <GLES2/gl2.h>
 #include <renderengine/RenderEngine.h>
 #include <renderengine/private/Description.h>
-#include <unordered_map>
 
 #define EGL_NO_CONFIG ((EGLConfig)0)
 
@@ -47,12 +48,14 @@
 
 class GLESRenderEngine : public impl::RenderEngine {
 public:
-    static std::unique_ptr<GLESRenderEngine> create(int hwcFormat, uint32_t featureFlags);
+    static std::unique_ptr<GLESRenderEngine> create(int hwcFormat, uint32_t featureFlags,
+                                                    uint32_t imageCacheSize);
     static EGLConfig chooseEglConfig(EGLDisplay display, int format, bool logConfig);
 
     GLESRenderEngine(uint32_t featureFlags, // See RenderEngine::FeatureFlag
                      EGLDisplay display, EGLConfig config, EGLContext ctxt, EGLSurface dummy,
-                     EGLContext protectedContext, EGLSurface protectedDummy);
+                     EGLContext protectedContext, EGLSurface protectedDummy,
+                     uint32_t imageCacheSize);
     ~GLESRenderEngine() override;
 
     std::unique_ptr<Framebuffer> createFramebuffer() override;
@@ -87,6 +90,8 @@
     // internal to RenderEngine
     EGLDisplay getEGLDisplay() const { return mEGLDisplay; }
     EGLConfig getEGLConfig() const { return mEGLConfig; }
+    // Creates an output image for rendering to
+    EGLImageKHR createFramebufferImageIfNeeded(ANativeWindowBuffer* nativeBuffer, bool isProtected);
 
 protected:
     Framebuffer* getFramebufferForDrawing() override;
@@ -176,6 +181,12 @@
     // If set to true, then enables tracing flush() and finish() to systrace.
     bool mTraceGpuCompletion = false;
     int32_t mFboHeight = 0;
+    // Maximum size of mFramebufferImageCache. If more images would be cached, then (approximately)
+    // the last recently used buffer should be kicked out.
+    uint32_t mFramebufferImageCacheSize = 0;
+
+    // Cache of output images, keyed by corresponding GraphicBuffer ID.
+    std::deque<std::pair<uint64_t, EGLImageKHR>> mFramebufferImageCache;
 
     // Current dataspace of layer being rendered
     ui::Dataspace mDataSpace = ui::Dataspace::UNKNOWN;
diff --git a/libs/renderengine/gl/GLFramebuffer.cpp b/libs/renderengine/gl/GLFramebuffer.cpp
index 0e3b405..c45598c 100644
--- a/libs/renderengine/gl/GLFramebuffer.cpp
+++ b/libs/renderengine/gl/GLFramebuffer.cpp
@@ -30,8 +30,8 @@
 namespace renderengine {
 namespace gl {
 
-GLFramebuffer::GLFramebuffer(const GLESRenderEngine& engine)
-      : mEGLDisplay(engine.getEGLDisplay()), mEGLImage(EGL_NO_IMAGE_KHR) {
+GLFramebuffer::GLFramebuffer(GLESRenderEngine& engine)
+      : mEngine(engine), mEGLDisplay(engine.getEGLDisplay()), mEGLImage(EGL_NO_IMAGE_KHR) {
     glGenTextures(1, &mTextureName);
     glGenFramebuffers(1, &mFramebufferName);
 }
@@ -39,26 +39,18 @@
 GLFramebuffer::~GLFramebuffer() {
     glDeleteFramebuffers(1, &mFramebufferName);
     glDeleteTextures(1, &mTextureName);
-    eglDestroyImageKHR(mEGLDisplay, mEGLImage);
 }
 
 bool GLFramebuffer::setNativeWindowBuffer(ANativeWindowBuffer* nativeBuffer, bool isProtected) {
     ATRACE_CALL();
     if (mEGLImage != EGL_NO_IMAGE_KHR) {
-        eglDestroyImageKHR(mEGLDisplay, mEGLImage);
         mEGLImage = EGL_NO_IMAGE_KHR;
         mBufferWidth = 0;
         mBufferHeight = 0;
     }
 
     if (nativeBuffer) {
-        EGLint attributes[] = {
-                isProtected ? EGL_PROTECTED_CONTENT_EXT : EGL_NONE,
-                isProtected ? EGL_TRUE : EGL_NONE,
-                EGL_NONE,
-        };
-        mEGLImage = eglCreateImageKHR(mEGLDisplay, EGL_NO_CONTEXT, EGL_NATIVE_BUFFER_ANDROID,
-                                      nativeBuffer, attributes);
+        mEGLImage = mEngine.createFramebufferImageIfNeeded(nativeBuffer, isProtected);
         if (mEGLImage == EGL_NO_IMAGE_KHR) {
             return false;
         }
diff --git a/libs/renderengine/gl/GLFramebuffer.h b/libs/renderengine/gl/GLFramebuffer.h
index 5043c59..1289fbf 100644
--- a/libs/renderengine/gl/GLFramebuffer.h
+++ b/libs/renderengine/gl/GLFramebuffer.h
@@ -32,7 +32,7 @@
 
 class GLFramebuffer : public renderengine::Framebuffer {
 public:
-    explicit GLFramebuffer(const GLESRenderEngine& engine);
+    explicit GLFramebuffer(GLESRenderEngine& engine);
     ~GLFramebuffer() override;
 
     bool setNativeWindowBuffer(ANativeWindowBuffer* nativeBuffer, bool isProtected) override;
@@ -43,6 +43,7 @@
     int32_t getBufferWidth() const { return mBufferWidth; }
 
 private:
+    GLESRenderEngine& mEngine;
     EGLDisplay mEGLDisplay;
     EGLImageKHR mEGLImage;
     uint32_t mTextureName, mFramebufferName;
diff --git a/libs/renderengine/include/renderengine/RenderEngine.h b/libs/renderengine/include/renderengine/RenderEngine.h
index 812d761..2a2b48f 100644
--- a/libs/renderengine/include/renderengine/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/RenderEngine.h
@@ -65,7 +65,8 @@
         USE_HIGH_PRIORITY_CONTEXT = 1 << 1, // Use high priority context
     };
 
-    static std::unique_ptr<impl::RenderEngine> create(int hwcFormat, uint32_t featureFlags);
+    static std::unique_ptr<impl::RenderEngine> create(int hwcFormat, uint32_t featureFlags,
+                                                      uint32_t imageCacheSize);
 
     virtual ~RenderEngine() = 0;
 
diff --git a/libs/renderengine/tests/RenderEngineTest.cpp b/libs/renderengine/tests/RenderEngineTest.cpp
index f28f672..a2bbaff 100644
--- a/libs/renderengine/tests/RenderEngineTest.cpp
+++ b/libs/renderengine/tests/RenderEngineTest.cpp
@@ -210,7 +210,7 @@
 };
 
 std::unique_ptr<renderengine::RenderEngine> RenderEngineTest::sRE =
-        renderengine::RenderEngine::create(static_cast<int32_t>(ui::PixelFormat::RGBA_8888), 0);
+        renderengine::RenderEngine::create(static_cast<int32_t>(ui::PixelFormat::RGBA_8888), 0, 1);
 
 struct ColorSourceVariant {
     static void fillColor(renderengine::LayerSettings& layer, half r, half g, half b,
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index df558e5..f8f258b 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -666,9 +666,10 @@
                             renderengine::RenderEngine::USE_HIGH_PRIORITY_CONTEXT : 0);
 
     // TODO(b/77156734): We need to stop casting and use HAL types when possible.
+    // Sending maxFrameBufferAcquiredBuffers as the cache size is tightly tuned to single-display.
     mCompositionEngine->setRenderEngine(
             renderengine::RenderEngine::create(static_cast<int32_t>(defaultCompositionPixelFormat),
-                                               renderEngineFeature));
+                                               renderEngineFeature, maxFrameBufferAcquiredBuffers));
 
     LOG_ALWAYS_FATAL_IF(mVrFlingerRequestsDisplay,
             "Starting with vr flinger active is not currently supported.");