SF: Predict HWC composition strategy
Asynchronously run ValidateDisplay to determine client composition
strategy. If we can predict that the composition strategy will not
change from frame to frame (for example by looking at whether
the geometry of the layers is changing), the hwc call is run
asynchronously with the gpu composition. If the result of the call is
incorrectly predicted, the gpu composition is rerun.
ValidateDisplay can take multiple milliseconds to complete and by
making it non-blocking in cases where we can predict the strategy
chosen by the hardware, we can jump start the client composition
and shave valuable milliseconds from the frame time.
This feature is disabled by default.
Test: perfetto traces
Bug: 220031739
Change-Id: Ia5f04f447455bba0bbebbe7642d8ade8313f381a
diff --git a/services/surfaceflinger/CompositionEngine/src/Display.cpp b/services/surfaceflinger/CompositionEngine/src/Display.cpp
index 54daf38..84c22cf 100644
--- a/services/surfaceflinger/CompositionEngine/src/Display.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Display.cpp
@@ -207,16 +207,8 @@
setReleasedLayers(std::move(releasedLayers));
}
-void Display::chooseCompositionStrategy() {
- ATRACE_CALL();
- ALOGV(__FUNCTION__);
-
- if (mIsDisconnected) {
- return;
- }
-
- // Default to the base settings -- client composition only.
- Output::chooseCompositionStrategy();
+void Display::beginFrame() {
+ Output::beginFrame();
// If we don't have a HWC display, then we are done.
const auto halDisplayId = HalDisplayId::tryCast(mId);
@@ -224,8 +216,6 @@
return;
}
- // Get any composition changes requested by the HWC device, and apply them.
- std::optional<android::HWComposer::DeviceRequestedChanges> changes;
auto& hwc = getCompositionEngine().getHwComposer();
if (const auto physicalDisplayId = PhysicalDisplayId::tryCast(*halDisplayId);
physicalDisplayId && getState().displayBrightness) {
@@ -237,17 +227,43 @@
ALOGE_IF(result != NO_ERROR, "setDisplayBrightness failed for %s: %d, (%s)",
getName().c_str(), result, strerror(-result));
}
+ // Clear out the display brightness now that it's been communicated to composer.
+ editState().displayBrightness.reset();
+}
+bool Display::chooseCompositionStrategy(
+ std::optional<android::HWComposer::DeviceRequestedChanges>* outChanges) {
+ ATRACE_CALL();
+ ALOGV(__FUNCTION__);
+
+ if (mIsDisconnected) {
+ return false;
+ }
+
+ // If we don't have a HWC display, then we are done.
+ const auto halDisplayId = HalDisplayId::tryCast(mId);
+ if (!halDisplayId) {
+ return false;
+ }
+
+ // Get any composition changes requested by the HWC device, and apply them.
+ std::optional<android::HWComposer::DeviceRequestedChanges> changes;
+ auto& hwc = getCompositionEngine().getHwComposer();
if (status_t result =
hwc.getDeviceCompositionChanges(*halDisplayId, anyLayersRequireClientComposition(),
getState().earliestPresentTime,
getState().previousPresentFence,
- getState().expectedPresentTime, &changes);
+ getState().expectedPresentTime, outChanges);
result != NO_ERROR) {
ALOGE("chooseCompositionStrategy failed for %s: %d (%s)", getName().c_str(), result,
strerror(-result));
- return;
+ return false;
}
+
+ return true;
+}
+
+void Display::applyCompositionStrategy(const std::optional<DeviceRequestedChanges>& changes) {
if (changes) {
applyChangedTypesToLayers(changes->changedTypes);
applyDisplayRequests(changes->displayRequests);
@@ -259,8 +275,6 @@
auto& state = editState();
state.usesClientComposition = anyLayersRequireClientComposition();
state.usesDeviceComposition = !allLayersRequireClientComposition();
- // Clear out the display brightness now that it's been communicated to composer.
- state.displayBrightness.reset();
}
bool Display::getSkipColorTransform() const {
@@ -273,12 +287,6 @@
return hwc.hasCapability(Capability::SKIP_CLIENT_COLOR_TRANSFORM);
}
-bool Display::anyLayersRequireClientComposition() const {
- const auto layers = getOutputLayersOrderedByZ();
- return std::any_of(layers.begin(), layers.end(),
- [](const auto& layer) { return layer->requiresClientComposition(); });
-}
-
bool Display::allLayersRequireClientComposition() const {
const auto layers = getOutputLayersOrderedByZ();
return std::all_of(layers.begin(), layers.end(),
@@ -379,7 +387,8 @@
}
}
-void Display::finishFrame(const compositionengine::CompositionRefreshArgs& refreshArgs) {
+void Display::finishFrame(const compositionengine::CompositionRefreshArgs& refreshArgs,
+ GpuCompositionResult&& result) {
// We only need to actually compose the display if:
// 1) It is being handled by hardware composer, which may need this to
// keep its virtual display state machine in sync, or
@@ -389,7 +398,7 @@
return;
}
- impl::Output::finishFrame(refreshArgs);
+ impl::Output::finishFrame(refreshArgs, std::move(result));
}
} // namespace android::compositionengine::impl
diff --git a/services/surfaceflinger/CompositionEngine/src/DisplaySurface.cpp b/services/surfaceflinger/CompositionEngine/src/DisplaySurface.cpp
index db6d4f2..28900af 100644
--- a/services/surfaceflinger/CompositionEngine/src/DisplaySurface.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/DisplaySurface.cpp
@@ -20,4 +20,8 @@
DisplaySurface::~DisplaySurface() = default;
+bool DisplaySurface::supportsCompositionStrategyPrediction() const {
+ return true;
+}
+
} // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/src/HwcAsyncWorker.cpp b/services/surfaceflinger/CompositionEngine/src/HwcAsyncWorker.cpp
new file mode 100644
index 0000000..6086f0b
--- /dev/null
+++ b/services/surfaceflinger/CompositionEngine/src/HwcAsyncWorker.cpp
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <compositionengine/impl/HwcAsyncWorker.h>
+#include <processgroup/sched_policy.h>
+#include <pthread.h>
+#include <sched.h>
+#include <sys/prctl.h>
+#include <sys/resource.h>
+#include <system/thread_defs.h>
+
+#include <android-base/thread_annotations.h>
+#include <cutils/sched_policy.h>
+
+namespace android::compositionengine::impl {
+
+HwcAsyncWorker::HwcAsyncWorker() {
+ mThread = std::thread(&HwcAsyncWorker::run, this);
+ pthread_setname_np(mThread.native_handle(), "HwcAsyncWorker");
+}
+
+HwcAsyncWorker::~HwcAsyncWorker() {
+ {
+ std::scoped_lock lock(mMutex);
+ mDone = true;
+ mCv.notify_all();
+ }
+ if (mThread.joinable()) {
+ mThread.join();
+ }
+}
+std::future<bool> HwcAsyncWorker::send(std::function<bool()> task) {
+ std::unique_lock<std::mutex> lock(mMutex);
+ android::base::ScopedLockAssertion assumeLock(mMutex);
+ mTask = std::packaged_task<bool()>([task = std::move(task)]() { return task(); });
+ mTaskRequested = true;
+ mCv.notify_one();
+ return mTask.get_future();
+}
+
+void HwcAsyncWorker::run() {
+ set_sched_policy(0, SP_FOREGROUND);
+ struct sched_param param = {0};
+ param.sched_priority = 2;
+ sched_setscheduler(gettid(), SCHED_FIFO, ¶m);
+
+ std::unique_lock<std::mutex> lock(mMutex);
+ android::base::ScopedLockAssertion assumeLock(mMutex);
+ while (!mDone) {
+ mCv.wait(lock);
+ if (mTaskRequested && mTask.valid()) {
+ mTask();
+ mTaskRequested = false;
+ }
+ }
+}
+
+} // namespace android::compositionengine::impl
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 25155b9..6595ed3 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -22,6 +22,7 @@
#include <compositionengine/LayerFE.h>
#include <compositionengine/LayerFECompositionState.h>
#include <compositionengine/RenderSurface.h>
+#include <compositionengine/impl/HwcAsyncWorker.h>
#include <compositionengine/impl/Output.h>
#include <compositionengine/impl/OutputCompositionState.h>
#include <compositionengine/impl/OutputLayer.h>
@@ -434,9 +435,17 @@
writeCompositionState(refreshArgs);
setColorTransform(refreshArgs);
beginFrame();
- prepareFrame();
+
+ GpuCompositionResult result;
+ const bool predictCompositionStrategy = canPredictCompositionStrategy(refreshArgs);
+ if (predictCompositionStrategy) {
+ result = prepareFrameAsync(refreshArgs);
+ } else {
+ prepareFrame();
+ }
+
devOptRepaintFlash(refreshArgs);
- finishFrame(refreshArgs);
+ finishFrame(refreshArgs, std::move(result));
postFramebuffer();
renderCachedSets(refreshArgs);
}
@@ -953,19 +962,72 @@
ATRACE_CALL();
ALOGV(__FUNCTION__);
- const auto& outputState = getState();
+ auto& outputState = editState();
if (!outputState.isEnabled) {
return;
}
- chooseCompositionStrategy();
+ std::optional<android::HWComposer::DeviceRequestedChanges> changes;
+ bool success = chooseCompositionStrategy(&changes);
+ resetCompositionStrategy();
+ outputState.previousDeviceRequestedChanges = changes;
+ outputState.previousDeviceRequestedSuccess = success;
+ if (success) {
+ applyCompositionStrategy(changes);
+ }
+ finishPrepareFrame();
+}
- if (mPlanner) {
- mPlanner->reportFinalPlan(getOutputLayersOrderedByZ());
+std::future<bool> Output::chooseCompositionStrategyAsync(
+ std::optional<android::HWComposer::DeviceRequestedChanges>* changes) {
+ return mHwComposerAsyncWorker->send(
+ [&, changes]() { return chooseCompositionStrategy(changes); });
+}
+
+GpuCompositionResult Output::prepareFrameAsync(const CompositionRefreshArgs& refreshArgs) {
+ ATRACE_CALL();
+ ALOGV(__FUNCTION__);
+ auto& state = editState();
+ const auto& previousChanges = state.previousDeviceRequestedChanges;
+ std::optional<android::HWComposer::DeviceRequestedChanges> changes;
+ resetCompositionStrategy();
+ auto hwcResult = chooseCompositionStrategyAsync(&changes);
+ if (state.previousDeviceRequestedSuccess) {
+ applyCompositionStrategy(previousChanges);
+ }
+ finishPrepareFrame();
+
+ base::unique_fd bufferFence;
+ std::shared_ptr<renderengine::ExternalTexture> buffer;
+ updateProtectedContentState();
+ const bool dequeueSucceeded = dequeueRenderBuffer(&bufferFence, &buffer);
+ GpuCompositionResult compositionResult;
+ if (dequeueSucceeded) {
+ std::optional<base::unique_fd> optFd =
+ composeSurfaces(Region::INVALID_REGION, refreshArgs, buffer, bufferFence);
+ if (optFd) {
+ compositionResult.fence = std::move(*optFd);
+ }
}
- mRenderSurface->prepareFrame(outputState.usesClientComposition,
- outputState.usesDeviceComposition);
+ auto chooseCompositionSuccess = hwcResult.get();
+ const bool predictionSucceeded = dequeueSucceeded && changes == previousChanges;
+ compositionResult.succeeded = predictionSucceeded;
+ if (!predictionSucceeded) {
+ ATRACE_NAME("CompositionStrategyPredictionMiss");
+ resetCompositionStrategy();
+ if (chooseCompositionSuccess) {
+ applyCompositionStrategy(changes);
+ }
+ finishPrepareFrame();
+ // Track the dequeued buffer to reuse so we don't need to dequeue another one.
+ compositionResult.buffer = buffer;
+ } else {
+ ATRACE_NAME("CompositionStrategyPredictionHit");
+ }
+ state.previousDeviceRequestedChanges = std::move(changes);
+ state.previousDeviceRequestedSuccess = chooseCompositionSuccess;
+ return compositionResult;
}
void Output::devOptRepaintFlash(const compositionengine::CompositionRefreshArgs& refreshArgs) {
@@ -975,7 +1037,11 @@
if (getState().isEnabled) {
if (const auto dirtyRegion = getDirtyRegion(); !dirtyRegion.isEmpty()) {
- static_cast<void>(composeSurfaces(dirtyRegion, refreshArgs));
+ base::unique_fd bufferFence;
+ std::shared_ptr<renderengine::ExternalTexture> buffer;
+ updateProtectedContentState();
+ dequeueRenderBuffer(&bufferFence, &buffer);
+ static_cast<void>(composeSurfaces(dirtyRegion, refreshArgs, buffer, bufferFence));
mRenderSurface->queueBuffer(base::unique_fd());
}
}
@@ -987,7 +1053,7 @@
prepareFrame();
}
-void Output::finishFrame(const compositionengine::CompositionRefreshArgs& refreshArgs) {
+void Output::finishFrame(const CompositionRefreshArgs& refreshArgs, GpuCompositionResult&& result) {
ATRACE_CALL();
ALOGV(__FUNCTION__);
@@ -995,9 +1061,25 @@
return;
}
- // Repaint the framebuffer (if needed), getting the optional fence for when
- // the composition completes.
- auto optReadyFence = composeSurfaces(Region::INVALID_REGION, refreshArgs);
+ std::optional<base::unique_fd> optReadyFence;
+ std::shared_ptr<renderengine::ExternalTexture> buffer;
+ base::unique_fd bufferFence;
+ if (result.succeeded) {
+ optReadyFence = std::move(result.fence);
+ } else {
+ if (result.bufferAvailable()) {
+ buffer = std::move(result.buffer);
+ bufferFence = std::move(result.fence);
+ } else {
+ updateProtectedContentState();
+ if (!dequeueRenderBuffer(&bufferFence, &buffer)) {
+ return;
+ }
+ }
+ // Repaint the framebuffer (if needed), getting the optional fence for when
+ // the composition completes.
+ optReadyFence = composeSurfaces(Region::INVALID_REGION, refreshArgs, buffer, bufferFence);
+ }
if (!optReadyFence) {
return;
}
@@ -1006,16 +1088,8 @@
mRenderSurface->queueBuffer(std::move(*optReadyFence));
}
-std::optional<base::unique_fd> Output::composeSurfaces(
- const Region& debugRegion, const compositionengine::CompositionRefreshArgs& refreshArgs) {
- ATRACE_CALL();
- ALOGV(__FUNCTION__);
-
+void Output::updateProtectedContentState() {
const auto& outputState = getState();
- OutputCompositionState& outputCompositionState = editState();
- const TracedOrdinal<bool> hasClientComposition = {"hasClientComposition",
- outputState.usesClientComposition};
-
auto& renderEngine = getCompositionEngine().getRenderEngine();
const bool supportsProtectedContent = renderEngine.supportsProtectedContent();
@@ -1037,29 +1111,48 @@
} else if (!outputState.isSecure && renderEngine.isProtected()) {
renderEngine.useProtectedContext(false);
}
+}
- base::unique_fd fd;
-
- std::shared_ptr<renderengine::ExternalTexture> tex;
+bool Output::dequeueRenderBuffer(base::unique_fd* bufferFence,
+ std::shared_ptr<renderengine::ExternalTexture>* tex) {
+ const auto& outputState = getState();
// If we aren't doing client composition on this output, but do have a
// flipClientTarget request for this frame on this output, we still need to
// dequeue a buffer.
- if (hasClientComposition || outputState.flipClientTarget) {
- tex = mRenderSurface->dequeueBuffer(&fd);
- if (tex == nullptr) {
+ if (outputState.usesClientComposition || outputState.flipClientTarget) {
+ *tex = mRenderSurface->dequeueBuffer(bufferFence);
+ if (*tex == nullptr) {
ALOGW("Dequeuing buffer for display [%s] failed, bailing out of "
"client composition for this frame",
mName.c_str());
- return {};
+ return false;
}
}
+ return true;
+}
+std::optional<base::unique_fd> Output::composeSurfaces(
+ const Region& debugRegion, const compositionengine::CompositionRefreshArgs& refreshArgs,
+ std::shared_ptr<renderengine::ExternalTexture> tex, base::unique_fd& fd) {
+ ATRACE_CALL();
+ ALOGV(__FUNCTION__);
+
+ const auto& outputState = getState();
+ const TracedOrdinal<bool> hasClientComposition = {"hasClientComposition",
+ outputState.usesClientComposition};
if (!hasClientComposition) {
setExpensiveRenderingExpected(false);
return base::unique_fd();
}
+ if (tex == nullptr) {
+ ALOGW("Buffer not valid for display [%s], bailing out of "
+ "client composition for this frame",
+ mName.c_str());
+ return {};
+ }
+
ALOGV("hasClientComposition");
renderengine::DisplaySettings clientCompositionDisplay;
@@ -1088,6 +1181,8 @@
outputState.usesDeviceComposition || getSkipColorTransform();
// Generate the client composition requests for the layers on this output.
+ auto& renderEngine = getCompositionEngine().getRenderEngine();
+ const bool supportsProtectedContent = renderEngine.supportsProtectedContent();
std::vector<LayerFE*> clientCompositionLayersFE;
std::vector<LayerFE::LayerSettings> clientCompositionLayers =
generateClientCompositionRequests(supportsProtectedContent,
@@ -1095,16 +1190,19 @@
clientCompositionLayersFE);
appendRegionFlashRequests(debugRegion, clientCompositionLayers);
+ OutputCompositionState& outputCompositionState = editState();
// Check if the client composition requests were rendered into the provided graphic buffer. If
// so, we can reuse the buffer and avoid client composition.
if (mClientCompositionRequestCache) {
if (mClientCompositionRequestCache->exists(tex->getBuffer()->getId(),
clientCompositionDisplay,
clientCompositionLayers)) {
+ ATRACE_NAME("ClientCompositionCacheHit");
outputCompositionState.reusedClientComposition = true;
setExpensiveRenderingExpected(false);
return base::unique_fd();
}
+ ATRACE_NAME("ClientCompositionCacheMiss");
mClientCompositionRequestCache->add(tex->getBuffer()->getId(), clientCompositionDisplay,
clientCompositionLayers);
}
@@ -1356,7 +1454,7 @@
outputState.dirtyRegion.set(outputState.displaySpace.getBoundsAsRect());
}
-void Output::chooseCompositionStrategy() {
+void Output::resetCompositionStrategy() {
// The base output implementation can only do client composition
auto& outputState = editState();
outputState.usesClientComposition = true;
@@ -1376,5 +1474,63 @@
return result;
}
+void Output::setPredictCompositionStrategy(bool predict) {
+ if (predict) {
+ mHwComposerAsyncWorker = std::make_unique<HwcAsyncWorker>();
+ } else {
+ mHwComposerAsyncWorker.reset(nullptr);
+ }
+}
+
+bool Output::canPredictCompositionStrategy(const CompositionRefreshArgs& refreshArgs) {
+ if (!getState().isEnabled || !mHwComposerAsyncWorker) {
+ ALOGV("canPredictCompositionStrategy disabled");
+ return false;
+ }
+
+ if (!getState().previousDeviceRequestedChanges) {
+ ALOGV("canPredictCompositionStrategy previous changes not available");
+ return false;
+ }
+
+ if (!mRenderSurface->supportsCompositionStrategyPrediction()) {
+ ALOGV("canPredictCompositionStrategy surface does not support");
+ return false;
+ }
+
+ if (refreshArgs.devOptFlashDirtyRegionsDelay) {
+ ALOGV("canPredictCompositionStrategy devOptFlashDirtyRegionsDelay");
+ return false;
+ }
+
+ // If no layer uses clientComposition, then don't predict composition strategy
+ // because we have less work to do in parallel.
+ if (!anyLayersRequireClientComposition()) {
+ ALOGV("canPredictCompositionStrategy no layer uses clientComposition");
+ return false;
+ }
+
+ if (!refreshArgs.updatingOutputGeometryThisFrame) {
+ return true;
+ }
+
+ ALOGV("canPredictCompositionStrategy updatingOutputGeometryThisFrame");
+ return false;
+}
+
+bool Output::anyLayersRequireClientComposition() const {
+ const auto layers = getOutputLayersOrderedByZ();
+ return std::any_of(layers.begin(), layers.end(),
+ [](const auto& layer) { return layer->requiresClientComposition(); });
+}
+
+void Output::finishPrepareFrame() {
+ const auto& state = getState();
+ if (mPlanner) {
+ mPlanner->reportFinalPlan(getOutputLayersOrderedByZ());
+ }
+ mRenderSurface->prepareFrame(state.usesClientComposition, state.usesDeviceComposition);
+}
+
} // namespace impl
} // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp b/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp
index 12c2c8e..5a3af7b 100644
--- a/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/RenderSurface.cpp
@@ -289,5 +289,9 @@
return mTexture;
}
+bool RenderSurface::supportsCompositionStrategyPrediction() const {
+ return mDisplaySurface->supportsCompositionStrategyPrediction();
+}
+
} // namespace impl
} // namespace android::compositionengine