services/surfaceflinger/Tracing/TransactionTracing.cpp - android_frameworks_native - Gitiles

 /*
  * Copyright 2021 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.
  */

 #undef LOG_TAG
 #define LOG_TAG "TransactionTracing"
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS

 #include <android-base/stringprintf.h>
 #include <log/log.h>
 #include <utils/SystemClock.h>
 #include <utils/Trace.h>

 #include "RingBuffer.h"
 #include "TransactionTracing.h"

 namespace android {

 TransactionTracing::TransactionTracing() {
     mBuffer = std::make_unique<
             RingBuffer<proto::TransactionTraceFile, proto::TransactionTraceEntry>>();
 }

 TransactionTracing::~TransactionTracing() = default;

 bool TransactionTracing::enable() {
     std::scoped_lock lock(mTraceLock);
     if (mEnabled) {
         return false;
     }
     mBuffer->setSize(mBufferSizeInBytes);
     mStartingTimestamp = systemTime();
     mEnabled = true;
     {
         std::scoped_lock lock(mMainThreadLock);
         mDone = false;
         mThread = std::thread(&TransactionTracing::loop, this);
     }
     return true;
 }

 bool TransactionTracing::disable() {
     std::thread thread;
     {
         std::scoped_lock lock(mMainThreadLock);
         mDone = true;
         mTransactionsAvailableCv.notify_all();
         thread = std::move(mThread);
     }
     if (thread.joinable()) {
         thread.join();
     }

     std::scoped_lock lock(mTraceLock);
     if (!mEnabled) {
         return false;
     }
     mEnabled = false;

     writeToFileLocked();
     mBuffer->reset();
     mQueuedTransactions.clear();
     mStartingStates.clear();
     mLayerHandles.clear();
     return true;
 }

 bool TransactionTracing::isEnabled() const {
     std::scoped_lock lock(mTraceLock);
     return mEnabled;
 }

 status_t TransactionTracing::writeToFile() {
     std::scoped_lock lock(mTraceLock);
     if (!mEnabled) {
         return STATUS_OK;
     }
     return writeToFileLocked();
 }

 status_t TransactionTracing::writeToFileLocked() {
     proto::TransactionTraceFile fileProto = createTraceFileProto();
     addStartingStateToProtoLocked(fileProto);
     return mBuffer->writeToFile(fileProto, FILE_NAME);
 }

 void TransactionTracing::setBufferSize(size_t bufferSizeInBytes) {
     std::scoped_lock lock(mTraceLock);
     mBufferSizeInBytes = bufferSizeInBytes;
     mBuffer->setSize(mBufferSizeInBytes);
 }

 proto::TransactionTraceFile TransactionTracing::createTraceFileProto() const {
     proto::TransactionTraceFile proto;
     proto.set_magic_number(uint64_t(proto::TransactionTraceFile_MagicNumber_MAGIC_NUMBER_H) << 32 |
                            proto::TransactionTraceFile_MagicNumber_MAGIC_NUMBER_L);
     return proto;
 }

 void TransactionTracing::dump(std::string& result) const {
     std::scoped_lock lock(mTraceLock);
     base::StringAppendF(&result, "Transaction tracing state: %s\n",
                         mEnabled ? "enabled" : "disabled");
     base::StringAppendF(&result,
                         "  queued transactions=%zu created layers=%zu handles=%zu states=%zu\n",
                         mQueuedTransactions.size(), mCreatedLayers.size(), mLayerHandles.size(),
                         mStartingStates.size());
     mBuffer->dump(result);
 }

 void TransactionTracing::addQueuedTransaction(const TransactionState& transaction) {
     std::scoped_lock lock(mTraceLock);
     ATRACE_CALL();
     if (!mEnabled) {
         return;
     }
     mQueuedTransactions[transaction.id] =
             TransactionProtoParser::toProto(transaction,
                                             std::bind(&TransactionTracing::getLayerIdLocked, this,
                                                       std::placeholders::_1),
                                             nullptr);
 }

 void TransactionTracing::addCommittedTransactions(std::vector<TransactionState>& transactions,
                                                   int64_t vsyncId) {
     CommittedTransactions committedTransactions;
     committedTransactions.vsyncId = vsyncId;
     committedTransactions.timestamp = systemTime();
     committedTransactions.transactionIds.reserve(transactions.size());
     for (const auto& transaction : transactions) {
         committedTransactions.transactionIds.emplace_back(transaction.id);
     }

     mPendingTransactions.emplace_back(committedTransactions);
     tryPushToTracingThread();
 }

 void TransactionTracing::loop() {
     while (true) {
         std::vector<CommittedTransactions> committedTransactions;
         std::vector<int32_t> removedLayers;
         {
             std::unique_lock<std::mutex> lock(mMainThreadLock);
             base::ScopedLockAssertion assumeLocked(mMainThreadLock);
             mTransactionsAvailableCv.wait(lock, [&]() REQUIRES(mMainThreadLock) {
                 return mDone || !mCommittedTransactions.empty();
             });
             if (mDone) {
                 mCommittedTransactions.clear();
                 mRemovedLayers.clear();
                 break;
             }

             removedLayers = std::move(mRemovedLayers);
             mRemovedLayers.clear();
             committedTransactions = std::move(mCommittedTransactions);
             mCommittedTransactions.clear();
         } // unlock mMainThreadLock

         addEntry(committedTransactions, removedLayers);
     }
 }

 void TransactionTracing::addEntry(const std::vector<CommittedTransactions>& committedTransactions,
                                   const std::vector<int32_t>& removedLayers) {
     ATRACE_CALL();
     std::scoped_lock lock(mTraceLock);
     std::vector<std::string> removedEntries;
     proto::TransactionTraceEntry entryProto;
     for (const CommittedTransactions& entry : committedTransactions) {
         entryProto.set_elapsed_realtime_nanos(entry.timestamp);
         entryProto.set_vsync_id(entry.vsyncId);
         entryProto.mutable_added_layers()->Reserve(static_cast<int32_t>(mCreatedLayers.size()));
         for (auto& newLayer : mCreatedLayers) {
             entryProto.mutable_added_layers()->Add(std::move(newLayer));
         }
         entryProto.mutable_removed_layers()->Reserve(static_cast<int32_t>(removedLayers.size()));
         for (auto& removedLayer : removedLayers) {
             entryProto.mutable_removed_layers()->Add(removedLayer);
         }
         mCreatedLayers.clear();
         entryProto.mutable_transactions()->Reserve(
                 static_cast<int32_t>(entry.transactionIds.size()));
         for (const uint64_t& id : entry.transactionIds) {
             auto it = mQueuedTransactions.find(id);
             if (it != mQueuedTransactions.end()) {
                 entryProto.mutable_transactions()->Add(std::move(it->second));
                 mQueuedTransactions.erase(it);
             } else {
                 ALOGW("Could not find transaction id %" PRIu64, id);
             }
         }

         std::string serializedProto;
         entryProto.SerializeToString(&serializedProto);
         entryProto.Clear();
         std::vector<std::string> entries = mBuffer->emplace(std::move(serializedProto));
         removedEntries.reserve(removedEntries.size() + entries.size());
         removedEntries.insert(removedEntries.end(), std::make_move_iterator(entries.begin()),
                               std::make_move_iterator(entries.end()));

         entryProto.mutable_removed_layer_handles()->Reserve(
                 static_cast<int32_t>(mRemovedLayerHandles.size()));
         for (auto& handle : mRemovedLayerHandles) {
             entryProto.mutable_removed_layer_handles()->Add(handle);
         }
         mRemovedLayerHandles.clear();
     }

     proto::TransactionTraceEntry removedEntryProto;
     for (const std::string& removedEntry : removedEntries) {
         removedEntryProto.ParseFromString(removedEntry);
         updateStartingStateLocked(removedEntryProto);
         removedEntryProto.Clear();
     }
     mTransactionsAddedToBufferCv.notify_one();
 }

 void TransactionTracing::flush(int64_t vsyncId) {
     while (!mPendingTransactions.empty() || !mPendingRemovedLayers.empty()) {
         tryPushToTracingThread();
     }
     std::unique_lock<std::mutex> lock(mTraceLock);
     base::ScopedLockAssertion assumeLocked(mTraceLock);
     mTransactionsAddedToBufferCv.wait(lock, [&]() REQUIRES(mTraceLock) {
         proto::TransactionTraceEntry entry;
         if (mBuffer->used() > 0) {
             entry.ParseFromString(mBuffer->back());
         }
         return mBuffer->used() > 0 && entry.vsync_id() >= vsyncId;
     });
 }

 void TransactionTracing::onLayerAdded(BBinder* layerHandle, int layerId, const std::string& name,
                                       uint32_t flags, int parentId) {
     std::scoped_lock lock(mTraceLock);
     TracingLayerCreationArgs args{layerId, name, flags, parentId, -1 /* mirrorFromId */};
     if (mLayerHandles.find(layerHandle) != mLayerHandles.end()) {
         ALOGW("Duplicate handles found. %p", layerHandle);
     }
     mLayerHandles[layerHandle] = layerId;
     proto::LayerCreationArgs protoArgs = TransactionProtoParser::toProto(args);
     proto::LayerCreationArgs protoArgsCopy = protoArgs;
     mCreatedLayers.push_back(protoArgs);
 }

 void TransactionTracing::onMirrorLayerAdded(BBinder* layerHandle, int layerId,
                                             const std::string& name, int mirrorFromId) {
     std::scoped_lock lock(mTraceLock);
     TracingLayerCreationArgs args{layerId, name, 0 /* flags */, -1 /* parentId */, mirrorFromId};
     if (mLayerHandles.find(layerHandle) != mLayerHandles.end()) {
         ALOGW("Duplicate handles found. %p", layerHandle);
     }
     mLayerHandles[layerHandle] = layerId;
     mCreatedLayers.emplace_back(TransactionProtoParser::toProto(args));
 }

 void TransactionTracing::onLayerRemoved(int32_t layerId) {
     mPendingRemovedLayers.emplace_back(layerId);
     tryPushToTracingThread();
 }

 void TransactionTracing::onHandleRemoved(BBinder* layerHandle) {
     std::scoped_lock lock(mTraceLock);
     auto it = mLayerHandles.find(layerHandle);
     if (it == mLayerHandles.end()) {
         ALOGW("handle not found. %p", layerHandle);
         return;
     }

     mRemovedLayerHandles.push_back(it->second);
     mLayerHandles.erase(it);
 }

 void TransactionTracing::tryPushToTracingThread() {
     // Try to acquire the lock from main thread.
     if (mMainThreadLock.try_lock()) {
         // We got the lock! Collect any pending transactions and continue.
         mCommittedTransactions.insert(mCommittedTransactions.end(),
                                       std::make_move_iterator(mPendingTransactions.begin()),
                                       std::make_move_iterator(mPendingTransactions.end()));
         mPendingTransactions.clear();
         mRemovedLayers.insert(mRemovedLayers.end(), mPendingRemovedLayers.begin(),
                               mPendingRemovedLayers.end());
         mPendingRemovedLayers.clear();
         mTransactionsAvailableCv.notify_one();
         mMainThreadLock.unlock();
     } else {
         ALOGV("Couldn't get lock");
     }
 }

 int32_t TransactionTracing::getLayerIdLocked(const sp<IBinder>& layerHandle) {
     if (layerHandle == nullptr) {
         return -1;
     }
     auto it = mLayerHandles.find(layerHandle->localBinder());
     if (it == mLayerHandles.end()) {
         ALOGW("Could not find layer handle %p", layerHandle->localBinder());
         return -1;
     }
     return it->second;
 }

 void TransactionTracing::updateStartingStateLocked(
         const proto::TransactionTraceEntry& removedEntry) {
     // Keep track of layer starting state so we can reconstruct the layer state as we purge
     // transactions from the buffer.
     for (const proto::LayerCreationArgs& addedLayer : removedEntry.added_layers()) {
         TracingLayerState& startingState = mStartingStates[addedLayer.layer_id()];
         startingState.layerId = addedLayer.layer_id();
         TransactionProtoParser::fromProto(addedLayer, startingState.args);
     }

     // Merge layer states to starting transaction state.
     for (const proto::TransactionState& transaction : removedEntry.transactions()) {
         for (const proto::LayerState& layerState : transaction.layer_changes()) {
             auto it = mStartingStates.find(layerState.layer_id());
             if (it == mStartingStates.end()) {
                 ALOGW("Could not find layer id %d", layerState.layer_id());
                 continue;
             }
             TransactionProtoParser::fromProto(layerState, nullptr, it->second);
         }
     }

     // Clean up stale starting states since the layer has been removed and the buffer does not
     // contain any references to the layer.
     for (const int32_t removedLayerId : removedEntry.removed_layers()) {
         mStartingStates.erase(removedLayerId);
     }
 }

 void TransactionTracing::addStartingStateToProtoLocked(proto::TransactionTraceFile& proto) {
     proto::TransactionTraceEntry* entryProto = proto.add_entry();
     entryProto->set_elapsed_realtime_nanos(mStartingTimestamp);
     entryProto->set_vsync_id(0);
     if (mStartingStates.size() == 0) {
         return;
     }

     entryProto->mutable_added_layers()->Reserve(static_cast<int32_t>(mStartingStates.size()));
     for (auto& [layerId, state] : mStartingStates) {
         entryProto->mutable_added_layers()->Add(TransactionProtoParser::toProto(state.args));
     }

     proto::TransactionState transactionProto = TransactionProtoParser::toProto(mStartingStates);
     transactionProto.set_vsync_id(0);
     transactionProto.set_post_time(mStartingTimestamp);
     entryProto->mutable_transactions()->Add(std::move(transactionProto));
 }

 proto::TransactionTraceFile TransactionTracing::writeToProto() {
     std::scoped_lock<std::mutex> lock(mTraceLock);
     proto::TransactionTraceFile proto = createTraceFileProto();
     addStartingStateToProtoLocked(proto);
     mBuffer->writeToProto(proto);
     return proto;
 }

 } // namespace android
	/*
	* Copyright 2021 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.
	*/

	#undef LOG_TAG
	#define LOG_TAG "TransactionTracing"
	#define ATRACE_TAG ATRACE_TAG_GRAPHICS

	#include <android-base/stringprintf.h>
	#include <log/log.h>
	#include <utils/SystemClock.h>
	#include <utils/Trace.h>

	#include "RingBuffer.h"
	#include "TransactionTracing.h"

	namespace android {

	TransactionTracing::TransactionTracing() {
	mBuffer = std::make_unique<
	RingBuffer<proto::TransactionTraceFile, proto::TransactionTraceEntry>>();
	}

	TransactionTracing::~TransactionTracing() = default;

	bool TransactionTracing::enable() {
	std::scoped_lock lock(mTraceLock);
	if (mEnabled) {
	return false;
	}
	mBuffer->setSize(mBufferSizeInBytes);
	mStartingTimestamp = systemTime();
	mEnabled = true;
	{
	std::scoped_lock lock(mMainThreadLock);
	mDone = false;
	mThread = std::thread(&TransactionTracing::loop, this);
	}
	return true;
	}

	bool TransactionTracing::disable() {
	std::thread thread;
	{
	std::scoped_lock lock(mMainThreadLock);
	mDone = true;
	mTransactionsAvailableCv.notify_all();
	thread = std::move(mThread);
	}
	if (thread.joinable()) {
	thread.join();
	}

	std::scoped_lock lock(mTraceLock);
	if (!mEnabled) {
	return false;
	}
	mEnabled = false;

	writeToFileLocked();
	mBuffer->reset();
	mQueuedTransactions.clear();
	mStartingStates.clear();
	mLayerHandles.clear();
	return true;
	}

	bool TransactionTracing::isEnabled() const {
	std::scoped_lock lock(mTraceLock);
	return mEnabled;
	}

	status_t TransactionTracing::writeToFile() {
	std::scoped_lock lock(mTraceLock);
	if (!mEnabled) {
	return STATUS_OK;
	}
	return writeToFileLocked();
	}

	status_t TransactionTracing::writeToFileLocked() {
	proto::TransactionTraceFile fileProto = createTraceFileProto();
	addStartingStateToProtoLocked(fileProto);
	return mBuffer->writeToFile(fileProto, FILE_NAME);
	}

	void TransactionTracing::setBufferSize(size_t bufferSizeInBytes) {
	std::scoped_lock lock(mTraceLock);
	mBufferSizeInBytes = bufferSizeInBytes;
	mBuffer->setSize(mBufferSizeInBytes);
	}

	proto::TransactionTraceFile TransactionTracing::createTraceFileProto() const {
	proto::TransactionTraceFile proto;
	proto.set_magic_number(uint64_t(proto::TransactionTraceFile_MagicNumber_MAGIC_NUMBER_H) << 32 \|
	proto::TransactionTraceFile_MagicNumber_MAGIC_NUMBER_L);
	return proto;
	}

	void TransactionTracing::dump(std::string& result) const {
	std::scoped_lock lock(mTraceLock);
	base::StringAppendF(&result, "Transaction tracing state: %s\n",
	mEnabled ? "enabled" : "disabled");
	base::StringAppendF(&result,
	" queued transactions=%zu created layers=%zu handles=%zu states=%zu\n",
	mQueuedTransactions.size(), mCreatedLayers.size(), mLayerHandles.size(),
	mStartingStates.size());
	mBuffer->dump(result);
	}

	void TransactionTracing::addQueuedTransaction(const TransactionState& transaction) {
	std::scoped_lock lock(mTraceLock);
	ATRACE_CALL();
	if (!mEnabled) {
	return;
	}
	mQueuedTransactions[transaction.id] =
	TransactionProtoParser::toProto(transaction,
	std::bind(&TransactionTracing::getLayerIdLocked, this,
	std::placeholders::_1),
	nullptr);
	}

	void TransactionTracing::addCommittedTransactions(std::vector<TransactionState>& transactions,
	int64_t vsyncId) {
	CommittedTransactions committedTransactions;
	committedTransactions.vsyncId = vsyncId;
	committedTransactions.timestamp = systemTime();
	committedTransactions.transactionIds.reserve(transactions.size());
	for (const auto& transaction : transactions) {
	committedTransactions.transactionIds.emplace_back(transaction.id);
	}

	mPendingTransactions.emplace_back(committedTransactions);
	tryPushToTracingThread();
	}

	void TransactionTracing::loop() {
	while (true) {
	std::vector<CommittedTransactions> committedTransactions;
	std::vector<int32_t> removedLayers;
	{
	std::unique_lock<std::mutex> lock(mMainThreadLock);
	base::ScopedLockAssertion assumeLocked(mMainThreadLock);
	mTransactionsAvailableCv.wait(lock, [&]() REQUIRES(mMainThreadLock) {
	return mDone \|\| !mCommittedTransactions.empty();
	});
	if (mDone) {
	mCommittedTransactions.clear();
	mRemovedLayers.clear();
	break;
	}

	removedLayers = std::move(mRemovedLayers);
	mRemovedLayers.clear();
	committedTransactions = std::move(mCommittedTransactions);
	mCommittedTransactions.clear();
	} // unlock mMainThreadLock

	addEntry(committedTransactions, removedLayers);
	}
	}

	void TransactionTracing::addEntry(const std::vector<CommittedTransactions>& committedTransactions,
	const std::vector<int32_t>& removedLayers) {
	ATRACE_CALL();
	std::scoped_lock lock(mTraceLock);
	std::vector<std::string> removedEntries;
	proto::TransactionTraceEntry entryProto;
	for (const CommittedTransactions& entry : committedTransactions) {
	entryProto.set_elapsed_realtime_nanos(entry.timestamp);
	entryProto.set_vsync_id(entry.vsyncId);
	entryProto.mutable_added_layers()->Reserve(static_cast<int32_t>(mCreatedLayers.size()));
	for (auto& newLayer : mCreatedLayers) {
	entryProto.mutable_added_layers()->Add(std::move(newLayer));
	}
	entryProto.mutable_removed_layers()->Reserve(static_cast<int32_t>(removedLayers.size()));
	for (auto& removedLayer : removedLayers) {
	entryProto.mutable_removed_layers()->Add(removedLayer);
	}
	mCreatedLayers.clear();
	entryProto.mutable_transactions()->Reserve(
	static_cast<int32_t>(entry.transactionIds.size()));
	for (const uint64_t& id : entry.transactionIds) {
	auto it = mQueuedTransactions.find(id);
	if (it != mQueuedTransactions.end()) {
	entryProto.mutable_transactions()->Add(std::move(it->second));
	mQueuedTransactions.erase(it);
	} else {
	ALOGW("Could not find transaction id %" PRIu64, id);
	}
	}

	std::string serializedProto;
	entryProto.SerializeToString(&serializedProto);
	entryProto.Clear();
	std::vector<std::string> entries = mBuffer->emplace(std::move(serializedProto));
	removedEntries.reserve(removedEntries.size() + entries.size());
	removedEntries.insert(removedEntries.end(), std::make_move_iterator(entries.begin()),
	std::make_move_iterator(entries.end()));

	entryProto.mutable_removed_layer_handles()->Reserve(
	static_cast<int32_t>(mRemovedLayerHandles.size()));
	for (auto& handle : mRemovedLayerHandles) {
	entryProto.mutable_removed_layer_handles()->Add(handle);
	}
	mRemovedLayerHandles.clear();
	}

	proto::TransactionTraceEntry removedEntryProto;
	for (const std::string& removedEntry : removedEntries) {
	removedEntryProto.ParseFromString(removedEntry);
	updateStartingStateLocked(removedEntryProto);
	removedEntryProto.Clear();
	}
	mTransactionsAddedToBufferCv.notify_one();
	}

	void TransactionTracing::flush(int64_t vsyncId) {
	while (!mPendingTransactions.empty() \|\| !mPendingRemovedLayers.empty()) {
	tryPushToTracingThread();
	}
	std::unique_lock<std::mutex> lock(mTraceLock);
	base::ScopedLockAssertion assumeLocked(mTraceLock);
	mTransactionsAddedToBufferCv.wait(lock, [&]() REQUIRES(mTraceLock) {
	proto::TransactionTraceEntry entry;
	if (mBuffer->used() > 0) {
	entry.ParseFromString(mBuffer->back());
	}
	return mBuffer->used() > 0 && entry.vsync_id() >= vsyncId;
	});
	}

	void TransactionTracing::onLayerAdded(BBinder* layerHandle, int layerId, const std::string& name,
	uint32_t flags, int parentId) {
	std::scoped_lock lock(mTraceLock);
	TracingLayerCreationArgs args{layerId, name, flags, parentId, -1 /* mirrorFromId */};
	if (mLayerHandles.find(layerHandle) != mLayerHandles.end()) {
	ALOGW("Duplicate handles found. %p", layerHandle);
	}
	mLayerHandles[layerHandle] = layerId;
	proto::LayerCreationArgs protoArgs = TransactionProtoParser::toProto(args);
	proto::LayerCreationArgs protoArgsCopy = protoArgs;
	mCreatedLayers.push_back(protoArgs);
	}

	void TransactionTracing::onMirrorLayerAdded(BBinder* layerHandle, int layerId,
	const std::string& name, int mirrorFromId) {
	std::scoped_lock lock(mTraceLock);
	TracingLayerCreationArgs args{layerId, name, 0 /* flags /, -1 / parentId */, mirrorFromId};
	if (mLayerHandles.find(layerHandle) != mLayerHandles.end()) {
	ALOGW("Duplicate handles found. %p", layerHandle);
	}
	mLayerHandles[layerHandle] = layerId;
	mCreatedLayers.emplace_back(TransactionProtoParser::toProto(args));
	}

	void TransactionTracing::onLayerRemoved(int32_t layerId) {
	mPendingRemovedLayers.emplace_back(layerId);
	tryPushToTracingThread();
	}

	void TransactionTracing::onHandleRemoved(BBinder* layerHandle) {
	std::scoped_lock lock(mTraceLock);
	auto it = mLayerHandles.find(layerHandle);
	if (it == mLayerHandles.end()) {
	ALOGW("handle not found. %p", layerHandle);
	return;
	}

	mRemovedLayerHandles.push_back(it->second);
	mLayerHandles.erase(it);
	}

	void TransactionTracing::tryPushToTracingThread() {
	// Try to acquire the lock from main thread.
	if (mMainThreadLock.try_lock()) {
	// We got the lock! Collect any pending transactions and continue.
	mCommittedTransactions.insert(mCommittedTransactions.end(),
	std::make_move_iterator(mPendingTransactions.begin()),
	std::make_move_iterator(mPendingTransactions.end()));
	mPendingTransactions.clear();
	mRemovedLayers.insert(mRemovedLayers.end(), mPendingRemovedLayers.begin(),
	mPendingRemovedLayers.end());
	mPendingRemovedLayers.clear();
	mTransactionsAvailableCv.notify_one();
	mMainThreadLock.unlock();
	} else {
	ALOGV("Couldn't get lock");
	}
	}

	int32_t TransactionTracing::getLayerIdLocked(const sp<IBinder>& layerHandle) {
	if (layerHandle == nullptr) {
	return -1;
	}
	auto it = mLayerHandles.find(layerHandle->localBinder());
	if (it == mLayerHandles.end()) {
	ALOGW("Could not find layer handle %p", layerHandle->localBinder());
	return -1;
	}
	return it->second;
	}

	void TransactionTracing::updateStartingStateLocked(
	const proto::TransactionTraceEntry& removedEntry) {
	// Keep track of layer starting state so we can reconstruct the layer state as we purge
	// transactions from the buffer.
	for (const proto::LayerCreationArgs& addedLayer : removedEntry.added_layers()) {
	TracingLayerState& startingState = mStartingStates[addedLayer.layer_id()];
	startingState.layerId = addedLayer.layer_id();
	TransactionProtoParser::fromProto(addedLayer, startingState.args);
	}

	// Merge layer states to starting transaction state.
	for (const proto::TransactionState& transaction : removedEntry.transactions()) {
	for (const proto::LayerState& layerState : transaction.layer_changes()) {
	auto it = mStartingStates.find(layerState.layer_id());
	if (it == mStartingStates.end()) {
	ALOGW("Could not find layer id %d", layerState.layer_id());
	continue;
	}
	TransactionProtoParser::fromProto(layerState, nullptr, it->second);
	}
	}

	// Clean up stale starting states since the layer has been removed and the buffer does not
	// contain any references to the layer.
	for (const int32_t removedLayerId : removedEntry.removed_layers()) {
	mStartingStates.erase(removedLayerId);
	}
	}

	void TransactionTracing::addStartingStateToProtoLocked(proto::TransactionTraceFile& proto) {
	proto::TransactionTraceEntry* entryProto = proto.add_entry();
	entryProto->set_elapsed_realtime_nanos(mStartingTimestamp);
	entryProto->set_vsync_id(0);
	if (mStartingStates.size() == 0) {
	return;
	}

	entryProto->mutable_added_layers()->Reserve(static_cast<int32_t>(mStartingStates.size()));
	for (auto& [layerId, state] : mStartingStates) {
	entryProto->mutable_added_layers()->Add(TransactionProtoParser::toProto(state.args));
	}

	proto::TransactionState transactionProto = TransactionProtoParser::toProto(mStartingStates);
	transactionProto.set_vsync_id(0);
	transactionProto.set_post_time(mStartingTimestamp);
	entryProto->mutable_transactions()->Add(std::move(transactionProto));
	}

	proto::TransactionTraceFile TransactionTracing::writeToProto() {
	std::scoped_lock<std::mutex> lock(mTraceLock);
	proto::TransactionTraceFile proto = createTraceFileProto();
	addStartingStateToProtoLocked(proto);
	mBuffer->writeToProto(proto);
	return proto;
	}

	} // namespace android