Relocate NN burst utility to ExecutionBurstUtils
This CL relocates serialize, deserialize, RequestChannelSender,
RequestChannelReceiver, ResultChannelSender, and ResultChannelReceiver
to ExecutionBurstUtils.
Bug: 177267324
Test: mma
Change-Id: Ie1fffdc89dc5bd325d3cd7806d2de632b8513cf9
Merged-In: Ie1fffdc89dc5bd325d3cd7806d2de632b8513cf9
(cherry picked from commit 297108360f2f97ec09d261bb10c5af0fa41e827a)
diff --git a/neuralnetworks/1.2/utils/src/ExecutionBurstUtils.cpp b/neuralnetworks/1.2/utils/src/ExecutionBurstUtils.cpp
new file mode 100644
index 0000000..f0275f9
--- /dev/null
+++ b/neuralnetworks/1.2/utils/src/ExecutionBurstUtils.cpp
@@ -0,0 +1,749 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#define LOG_TAG "ExecutionBurstUtils"
+
+#include "ExecutionBurstUtils.h"
+
+#include <android-base/logging.h>
+#include <android/hardware/neuralnetworks/1.0/types.h>
+#include <android/hardware/neuralnetworks/1.1/types.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <fmq/MessageQueue.h>
+#include <hidl/MQDescriptor.h>
+
+#include <atomic>
+#include <chrono>
+#include <memory>
+#include <thread>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+namespace {
+
+constexpr V1_2::Timing kNoTiming = {std::numeric_limits<uint64_t>::max(),
+ std::numeric_limits<uint64_t>::max()};
+
+}
+
+// serialize a request into a packet
+std::vector<FmqRequestDatum> serialize(const V1_0::Request& request, V1_2::MeasureTiming measure,
+ const std::vector<int32_t>& slots) {
+ // count how many elements need to be sent for a request
+ size_t count = 2 + request.inputs.size() + request.outputs.size() + request.pools.size();
+ for (const auto& input : request.inputs) {
+ count += input.dimensions.size();
+ }
+ for (const auto& output : request.outputs) {
+ count += output.dimensions.size();
+ }
+
+ // create buffer to temporarily store elements
+ std::vector<FmqRequestDatum> data;
+ data.reserve(count);
+
+ // package packetInfo
+ {
+ FmqRequestDatum datum;
+ datum.packetInformation(
+ {/*.packetSize=*/static_cast<uint32_t>(count),
+ /*.numberOfInputOperands=*/static_cast<uint32_t>(request.inputs.size()),
+ /*.numberOfOutputOperands=*/static_cast<uint32_t>(request.outputs.size()),
+ /*.numberOfPools=*/static_cast<uint32_t>(request.pools.size())});
+ data.push_back(datum);
+ }
+
+ // package input data
+ for (const auto& input : request.inputs) {
+ // package operand information
+ FmqRequestDatum datum;
+ datum.inputOperandInformation(
+ {/*.hasNoValue=*/input.hasNoValue,
+ /*.location=*/input.location,
+ /*.numberOfDimensions=*/static_cast<uint32_t>(input.dimensions.size())});
+ data.push_back(datum);
+
+ // package operand dimensions
+ for (uint32_t dimension : input.dimensions) {
+ FmqRequestDatum datum;
+ datum.inputOperandDimensionValue(dimension);
+ data.push_back(datum);
+ }
+ }
+
+ // package output data
+ for (const auto& output : request.outputs) {
+ // package operand information
+ FmqRequestDatum datum;
+ datum.outputOperandInformation(
+ {/*.hasNoValue=*/output.hasNoValue,
+ /*.location=*/output.location,
+ /*.numberOfDimensions=*/static_cast<uint32_t>(output.dimensions.size())});
+ data.push_back(datum);
+
+ // package operand dimensions
+ for (uint32_t dimension : output.dimensions) {
+ FmqRequestDatum datum;
+ datum.outputOperandDimensionValue(dimension);
+ data.push_back(datum);
+ }
+ }
+
+ // package pool identifier
+ for (int32_t slot : slots) {
+ FmqRequestDatum datum;
+ datum.poolIdentifier(slot);
+ data.push_back(datum);
+ }
+
+ // package measureTiming
+ {
+ FmqRequestDatum datum;
+ datum.measureTiming(measure);
+ data.push_back(datum);
+ }
+
+ // return packet
+ return data;
+}
+
+// serialize result
+std::vector<FmqResultDatum> serialize(V1_0::ErrorStatus errorStatus,
+ const std::vector<V1_2::OutputShape>& outputShapes,
+ V1_2::Timing timing) {
+ // count how many elements need to be sent for a request
+ size_t count = 2 + outputShapes.size();
+ for (const auto& outputShape : outputShapes) {
+ count += outputShape.dimensions.size();
+ }
+
+ // create buffer to temporarily store elements
+ std::vector<FmqResultDatum> data;
+ data.reserve(count);
+
+ // package packetInfo
+ {
+ FmqResultDatum datum;
+ datum.packetInformation({/*.packetSize=*/static_cast<uint32_t>(count),
+ /*.errorStatus=*/errorStatus,
+ /*.numberOfOperands=*/static_cast<uint32_t>(outputShapes.size())});
+ data.push_back(datum);
+ }
+
+ // package output shape data
+ for (const auto& operand : outputShapes) {
+ // package operand information
+ FmqResultDatum::OperandInformation info{};
+ info.isSufficient = operand.isSufficient;
+ info.numberOfDimensions = static_cast<uint32_t>(operand.dimensions.size());
+
+ FmqResultDatum datum;
+ datum.operandInformation(info);
+ data.push_back(datum);
+
+ // package operand dimensions
+ for (uint32_t dimension : operand.dimensions) {
+ FmqResultDatum datum;
+ datum.operandDimensionValue(dimension);
+ data.push_back(datum);
+ }
+ }
+
+ // package executionTiming
+ {
+ FmqResultDatum datum;
+ datum.executionTiming(timing);
+ data.push_back(datum);
+ }
+
+ // return result
+ return data;
+}
+
+// deserialize request
+std::optional<std::tuple<V1_0::Request, std::vector<int32_t>, V1_2::MeasureTiming>> deserialize(
+ const std::vector<FmqRequestDatum>& data) {
+ using discriminator = FmqRequestDatum::hidl_discriminator;
+
+ size_t index = 0;
+
+ // validate packet information
+ if (data.size() == 0 || data[index].getDiscriminator() != discriminator::packetInformation) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage packet information
+ const FmqRequestDatum::PacketInformation& packetInfo = data[index].packetInformation();
+ index++;
+ const uint32_t packetSize = packetInfo.packetSize;
+ const uint32_t numberOfInputOperands = packetInfo.numberOfInputOperands;
+ const uint32_t numberOfOutputOperands = packetInfo.numberOfOutputOperands;
+ const uint32_t numberOfPools = packetInfo.numberOfPools;
+
+ // verify packet size
+ if (data.size() != packetSize) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage input operands
+ std::vector<V1_0::RequestArgument> inputs;
+ inputs.reserve(numberOfInputOperands);
+ for (size_t operand = 0; operand < numberOfInputOperands; ++operand) {
+ // validate input operand information
+ if (data[index].getDiscriminator() != discriminator::inputOperandInformation) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage operand information
+ const FmqRequestDatum::OperandInformation& operandInfo =
+ data[index].inputOperandInformation();
+ index++;
+ const bool hasNoValue = operandInfo.hasNoValue;
+ const V1_0::DataLocation location = operandInfo.location;
+ const uint32_t numberOfDimensions = operandInfo.numberOfDimensions;
+
+ // unpackage operand dimensions
+ std::vector<uint32_t> dimensions;
+ dimensions.reserve(numberOfDimensions);
+ for (size_t i = 0; i < numberOfDimensions; ++i) {
+ // validate dimension
+ if (data[index].getDiscriminator() != discriminator::inputOperandDimensionValue) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage dimension
+ const uint32_t dimension = data[index].inputOperandDimensionValue();
+ index++;
+
+ // store result
+ dimensions.push_back(dimension);
+ }
+
+ // store result
+ inputs.push_back(
+ {/*.hasNoValue=*/hasNoValue, /*.location=*/location, /*.dimensions=*/dimensions});
+ }
+
+ // unpackage output operands
+ std::vector<V1_0::RequestArgument> outputs;
+ outputs.reserve(numberOfOutputOperands);
+ for (size_t operand = 0; operand < numberOfOutputOperands; ++operand) {
+ // validate output operand information
+ if (data[index].getDiscriminator() != discriminator::outputOperandInformation) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage operand information
+ const FmqRequestDatum::OperandInformation& operandInfo =
+ data[index].outputOperandInformation();
+ index++;
+ const bool hasNoValue = operandInfo.hasNoValue;
+ const V1_0::DataLocation location = operandInfo.location;
+ const uint32_t numberOfDimensions = operandInfo.numberOfDimensions;
+
+ // unpackage operand dimensions
+ std::vector<uint32_t> dimensions;
+ dimensions.reserve(numberOfDimensions);
+ for (size_t i = 0; i < numberOfDimensions; ++i) {
+ // validate dimension
+ if (data[index].getDiscriminator() != discriminator::outputOperandDimensionValue) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage dimension
+ const uint32_t dimension = data[index].outputOperandDimensionValue();
+ index++;
+
+ // store result
+ dimensions.push_back(dimension);
+ }
+
+ // store result
+ outputs.push_back(
+ {/*.hasNoValue=*/hasNoValue, /*.location=*/location, /*.dimensions=*/dimensions});
+ }
+
+ // unpackage pools
+ std::vector<int32_t> slots;
+ slots.reserve(numberOfPools);
+ for (size_t pool = 0; pool < numberOfPools; ++pool) {
+ // validate input operand information
+ if (data[index].getDiscriminator() != discriminator::poolIdentifier) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage operand information
+ const int32_t poolId = data[index].poolIdentifier();
+ index++;
+
+ // store result
+ slots.push_back(poolId);
+ }
+
+ // validate measureTiming
+ if (data[index].getDiscriminator() != discriminator::measureTiming) {
+ LOG(ERROR) << "FMQ Request packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage measureTiming
+ const V1_2::MeasureTiming measure = data[index].measureTiming();
+ index++;
+
+ // validate packet information
+ if (index != packetSize) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // return request
+ V1_0::Request request = {/*.inputs=*/inputs, /*.outputs=*/outputs, /*.pools=*/{}};
+ return std::make_tuple(std::move(request), std::move(slots), measure);
+}
+
+// deserialize a packet into the result
+std::optional<std::tuple<V1_0::ErrorStatus, std::vector<V1_2::OutputShape>, V1_2::Timing>>
+deserialize(const std::vector<FmqResultDatum>& data) {
+ using discriminator = FmqResultDatum::hidl_discriminator;
+
+ std::vector<V1_2::OutputShape> outputShapes;
+ size_t index = 0;
+
+ // validate packet information
+ if (data.size() == 0 || data[index].getDiscriminator() != discriminator::packetInformation) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage packet information
+ const FmqResultDatum::PacketInformation& packetInfo = data[index].packetInformation();
+ index++;
+ const uint32_t packetSize = packetInfo.packetSize;
+ const V1_0::ErrorStatus errorStatus = packetInfo.errorStatus;
+ const uint32_t numberOfOperands = packetInfo.numberOfOperands;
+
+ // verify packet size
+ if (data.size() != packetSize) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage operands
+ for (size_t operand = 0; operand < numberOfOperands; ++operand) {
+ // validate operand information
+ if (data[index].getDiscriminator() != discriminator::operandInformation) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage operand information
+ const FmqResultDatum::OperandInformation& operandInfo = data[index].operandInformation();
+ index++;
+ const bool isSufficient = operandInfo.isSufficient;
+ const uint32_t numberOfDimensions = operandInfo.numberOfDimensions;
+
+ // unpackage operand dimensions
+ std::vector<uint32_t> dimensions;
+ dimensions.reserve(numberOfDimensions);
+ for (size_t i = 0; i < numberOfDimensions; ++i) {
+ // validate dimension
+ if (data[index].getDiscriminator() != discriminator::operandDimensionValue) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage dimension
+ const uint32_t dimension = data[index].operandDimensionValue();
+ index++;
+
+ // store result
+ dimensions.push_back(dimension);
+ }
+
+ // store result
+ outputShapes.push_back({/*.dimensions=*/dimensions, /*.isSufficient=*/isSufficient});
+ }
+
+ // validate execution timing
+ if (data[index].getDiscriminator() != discriminator::executionTiming) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // unpackage execution timing
+ const V1_2::Timing timing = data[index].executionTiming();
+ index++;
+
+ // validate packet information
+ if (index != packetSize) {
+ LOG(ERROR) << "FMQ Result packet ill-formed";
+ return std::nullopt;
+ }
+
+ // return result
+ return std::make_tuple(errorStatus, std::move(outputShapes), timing);
+}
+
+V1_0::ErrorStatus legacyConvertResultCodeToErrorStatus(int resultCode) {
+ return convertToV1_0(convertResultCodeToErrorStatus(resultCode));
+}
+
+// RequestChannelSender methods
+
+std::pair<std::unique_ptr<RequestChannelSender>, const FmqRequestDescriptor*>
+RequestChannelSender::create(size_t channelLength) {
+ std::unique_ptr<FmqRequestChannel> fmqRequestChannel =
+ std::make_unique<FmqRequestChannel>(channelLength, /*confEventFlag=*/true);
+ if (!fmqRequestChannel->isValid()) {
+ LOG(ERROR) << "Unable to create RequestChannelSender";
+ return {nullptr, nullptr};
+ }
+
+ const FmqRequestDescriptor* descriptor = fmqRequestChannel->getDesc();
+ return std::make_pair(std::make_unique<RequestChannelSender>(std::move(fmqRequestChannel)),
+ descriptor);
+}
+
+RequestChannelSender::RequestChannelSender(std::unique_ptr<FmqRequestChannel> fmqRequestChannel)
+ : mFmqRequestChannel(std::move(fmqRequestChannel)) {}
+
+bool RequestChannelSender::send(const V1_0::Request& request, V1_2::MeasureTiming measure,
+ const std::vector<int32_t>& slots) {
+ const std::vector<FmqRequestDatum> serialized = serialize(request, measure, slots);
+ return sendPacket(serialized);
+}
+
+bool RequestChannelSender::sendPacket(const std::vector<FmqRequestDatum>& packet) {
+ if (!mValid) {
+ return false;
+ }
+
+ if (packet.size() > mFmqRequestChannel->availableToWrite()) {
+ LOG(ERROR)
+ << "RequestChannelSender::sendPacket -- packet size exceeds size available in FMQ";
+ return false;
+ }
+
+ // Always send the packet with "blocking" because this signals the futex and
+ // unblocks the consumer if it is waiting on the futex.
+ return mFmqRequestChannel->writeBlocking(packet.data(), packet.size());
+}
+
+void RequestChannelSender::invalidate() {
+ mValid = false;
+}
+
+// RequestChannelReceiver methods
+
+std::unique_ptr<RequestChannelReceiver> RequestChannelReceiver::create(
+ const FmqRequestDescriptor& requestChannel, std::chrono::microseconds pollingTimeWindow) {
+ std::unique_ptr<FmqRequestChannel> fmqRequestChannel =
+ std::make_unique<FmqRequestChannel>(requestChannel);
+
+ if (!fmqRequestChannel->isValid()) {
+ LOG(ERROR) << "Unable to create RequestChannelReceiver";
+ return nullptr;
+ }
+ if (fmqRequestChannel->getEventFlagWord() == nullptr) {
+ LOG(ERROR)
+ << "RequestChannelReceiver::create was passed an MQDescriptor without an EventFlag";
+ return nullptr;
+ }
+
+ return std::make_unique<RequestChannelReceiver>(std::move(fmqRequestChannel),
+ pollingTimeWindow);
+}
+
+RequestChannelReceiver::RequestChannelReceiver(std::unique_ptr<FmqRequestChannel> fmqRequestChannel,
+ std::chrono::microseconds pollingTimeWindow)
+ : mFmqRequestChannel(std::move(fmqRequestChannel)), kPollingTimeWindow(pollingTimeWindow) {}
+
+std::optional<std::tuple<V1_0::Request, std::vector<int32_t>, V1_2::MeasureTiming>>
+RequestChannelReceiver::getBlocking() {
+ const auto packet = getPacketBlocking();
+ if (!packet) {
+ return std::nullopt;
+ }
+
+ return deserialize(*packet);
+}
+
+void RequestChannelReceiver::invalidate() {
+ mTeardown = true;
+
+ // force unblock
+ // ExecutionBurstServer is by default waiting on a request packet. If the
+ // client process destroys its burst object, the server may still be waiting
+ // on the futex. This force unblock wakes up any thread waiting on the
+ // futex.
+ // TODO: look for a different/better way to signal/notify the futex to wake
+ // up any thread waiting on it
+ FmqRequestDatum datum;
+ datum.packetInformation({/*.packetSize=*/0, /*.numberOfInputOperands=*/0,
+ /*.numberOfOutputOperands=*/0, /*.numberOfPools=*/0});
+ mFmqRequestChannel->writeBlocking(&datum, 1);
+}
+
+std::optional<std::vector<FmqRequestDatum>> RequestChannelReceiver::getPacketBlocking() {
+ if (mTeardown) {
+ return std::nullopt;
+ }
+
+ // First spend time polling if results are available in FMQ instead of
+ // waiting on the futex. Polling is more responsive (yielding lower
+ // latencies), but can take up more power, so only poll for a limited period
+ // of time.
+
+ auto& getCurrentTime = std::chrono::high_resolution_clock::now;
+ const auto timeToStopPolling = getCurrentTime() + kPollingTimeWindow;
+
+ while (getCurrentTime() < timeToStopPolling) {
+ // if class is being torn down, immediately return
+ if (mTeardown.load(std::memory_order_relaxed)) {
+ return std::nullopt;
+ }
+
+ // Check if data is available. If it is, immediately retrieve it and
+ // return.
+ const size_t available = mFmqRequestChannel->availableToRead();
+ if (available > 0) {
+ // This is the first point when we know an execution is occurring,
+ // so begin to collect systraces. Note that a similar systrace does
+ // not exist at the corresponding point in
+ // ResultChannelReceiver::getPacketBlocking because the execution is
+ // already in flight.
+ NNTRACE_FULL(NNTRACE_LAYER_IPC, NNTRACE_PHASE_EXECUTION,
+ "ExecutionBurstServer getting packet");
+ std::vector<FmqRequestDatum> packet(available);
+ const bool success = mFmqRequestChannel->read(packet.data(), available);
+ if (!success) {
+ LOG(ERROR) << "Error receiving packet";
+ return std::nullopt;
+ }
+ return std::make_optional(std::move(packet));
+ }
+ }
+
+ // If we get to this point, we either stopped polling because it was taking
+ // too long or polling was not allowed. Instead, perform a blocking call
+ // which uses a futex to save power.
+
+ // wait for request packet and read first element of request packet
+ FmqRequestDatum datum;
+ bool success = mFmqRequestChannel->readBlocking(&datum, 1);
+
+ // This is the first point when we know an execution is occurring, so begin
+ // to collect systraces. Note that a similar systrace does not exist at the
+ // corresponding point in ResultChannelReceiver::getPacketBlocking because
+ // the execution is already in flight.
+ NNTRACE_FULL(NNTRACE_LAYER_IPC, NNTRACE_PHASE_EXECUTION, "ExecutionBurstServer getting packet");
+
+ // retrieve remaining elements
+ // NOTE: all of the data is already available at this point, so there's no
+ // need to do a blocking wait to wait for more data. This is known because
+ // in FMQ, all writes are published (made available) atomically. Currently,
+ // the producer always publishes the entire packet in one function call, so
+ // if the first element of the packet is available, the remaining elements
+ // are also available.
+ const size_t count = mFmqRequestChannel->availableToRead();
+ std::vector<FmqRequestDatum> packet(count + 1);
+ std::memcpy(&packet.front(), &datum, sizeof(datum));
+ success &= mFmqRequestChannel->read(packet.data() + 1, count);
+
+ // terminate loop
+ if (mTeardown) {
+ return std::nullopt;
+ }
+
+ // ensure packet was successfully received
+ if (!success) {
+ LOG(ERROR) << "Error receiving packet";
+ return std::nullopt;
+ }
+
+ return std::make_optional(std::move(packet));
+}
+
+// ResultChannelSender methods
+
+std::unique_ptr<ResultChannelSender> ResultChannelSender::create(
+ const FmqResultDescriptor& resultChannel) {
+ std::unique_ptr<FmqResultChannel> fmqResultChannel =
+ std::make_unique<FmqResultChannel>(resultChannel);
+
+ if (!fmqResultChannel->isValid()) {
+ LOG(ERROR) << "Unable to create RequestChannelSender";
+ return nullptr;
+ }
+ if (fmqResultChannel->getEventFlagWord() == nullptr) {
+ LOG(ERROR) << "ResultChannelSender::create was passed an MQDescriptor without an EventFlag";
+ return nullptr;
+ }
+
+ return std::make_unique<ResultChannelSender>(std::move(fmqResultChannel));
+}
+
+ResultChannelSender::ResultChannelSender(std::unique_ptr<FmqResultChannel> fmqResultChannel)
+ : mFmqResultChannel(std::move(fmqResultChannel)) {}
+
+bool ResultChannelSender::send(V1_0::ErrorStatus errorStatus,
+ const std::vector<V1_2::OutputShape>& outputShapes,
+ V1_2::Timing timing) {
+ const std::vector<FmqResultDatum> serialized = serialize(errorStatus, outputShapes, timing);
+ return sendPacket(serialized);
+}
+
+bool ResultChannelSender::sendPacket(const std::vector<FmqResultDatum>& packet) {
+ if (packet.size() > mFmqResultChannel->availableToWrite()) {
+ LOG(ERROR)
+ << "ResultChannelSender::sendPacket -- packet size exceeds size available in FMQ";
+ const std::vector<FmqResultDatum> errorPacket =
+ serialize(V1_0::ErrorStatus::GENERAL_FAILURE, {}, kNoTiming);
+
+ // Always send the packet with "blocking" because this signals the futex
+ // and unblocks the consumer if it is waiting on the futex.
+ return mFmqResultChannel->writeBlocking(errorPacket.data(), errorPacket.size());
+ }
+
+ // Always send the packet with "blocking" because this signals the futex and
+ // unblocks the consumer if it is waiting on the futex.
+ return mFmqResultChannel->writeBlocking(packet.data(), packet.size());
+}
+
+// ResultChannelReceiver methods
+
+std::pair<std::unique_ptr<ResultChannelReceiver>, const FmqResultDescriptor*>
+ResultChannelReceiver::create(size_t channelLength, std::chrono::microseconds pollingTimeWindow) {
+ std::unique_ptr<FmqResultChannel> fmqResultChannel =
+ std::make_unique<FmqResultChannel>(channelLength, /*confEventFlag=*/true);
+ if (!fmqResultChannel->isValid()) {
+ LOG(ERROR) << "Unable to create ResultChannelReceiver";
+ return {nullptr, nullptr};
+ }
+
+ const FmqResultDescriptor* descriptor = fmqResultChannel->getDesc();
+ return std::make_pair(
+ std::make_unique<ResultChannelReceiver>(std::move(fmqResultChannel), pollingTimeWindow),
+ descriptor);
+}
+
+ResultChannelReceiver::ResultChannelReceiver(std::unique_ptr<FmqResultChannel> fmqResultChannel,
+ std::chrono::microseconds pollingTimeWindow)
+ : mFmqResultChannel(std::move(fmqResultChannel)), kPollingTimeWindow(pollingTimeWindow) {}
+
+std::optional<std::tuple<V1_0::ErrorStatus, std::vector<V1_2::OutputShape>, V1_2::Timing>>
+ResultChannelReceiver::getBlocking() {
+ const auto packet = getPacketBlocking();
+ if (!packet) {
+ return std::nullopt;
+ }
+
+ return deserialize(*packet);
+}
+
+void ResultChannelReceiver::invalidate() {
+ mValid = false;
+
+ // force unblock
+ // ExecutionBurstController waits on a result packet after sending a
+ // request. If the driver containing ExecutionBurstServer crashes, the
+ // controller may be waiting on the futex. This force unblock wakes up any
+ // thread waiting on the futex.
+ // TODO: look for a different/better way to signal/notify the futex to
+ // wake up any thread waiting on it
+ FmqResultDatum datum;
+ datum.packetInformation({/*.packetSize=*/0,
+ /*.errorStatus=*/V1_0::ErrorStatus::GENERAL_FAILURE,
+ /*.numberOfOperands=*/0});
+ mFmqResultChannel->writeBlocking(&datum, 1);
+}
+
+std::optional<std::vector<FmqResultDatum>> ResultChannelReceiver::getPacketBlocking() {
+ if (!mValid) {
+ return std::nullopt;
+ }
+
+ // First spend time polling if results are available in FMQ instead of
+ // waiting on the futex. Polling is more responsive (yielding lower
+ // latencies), but can take up more power, so only poll for a limited period
+ // of time.
+
+ auto& getCurrentTime = std::chrono::high_resolution_clock::now;
+ const auto timeToStopPolling = getCurrentTime() + kPollingTimeWindow;
+
+ while (getCurrentTime() < timeToStopPolling) {
+ // if class is being torn down, immediately return
+ if (!mValid.load(std::memory_order_relaxed)) {
+ return std::nullopt;
+ }
+
+ // Check if data is available. If it is, immediately retrieve it and
+ // return.
+ const size_t available = mFmqResultChannel->availableToRead();
+ if (available > 0) {
+ std::vector<FmqResultDatum> packet(available);
+ const bool success = mFmqResultChannel->read(packet.data(), available);
+ if (!success) {
+ LOG(ERROR) << "Error receiving packet";
+ return std::nullopt;
+ }
+ return std::make_optional(std::move(packet));
+ }
+ }
+
+ // If we get to this point, we either stopped polling because it was taking
+ // too long or polling was not allowed. Instead, perform a blocking call
+ // which uses a futex to save power.
+
+ // wait for result packet and read first element of result packet
+ FmqResultDatum datum;
+ bool success = mFmqResultChannel->readBlocking(&datum, 1);
+
+ // retrieve remaining elements
+ // NOTE: all of the data is already available at this point, so there's no
+ // need to do a blocking wait to wait for more data. This is known because
+ // in FMQ, all writes are published (made available) atomically. Currently,
+ // the producer always publishes the entire packet in one function call, so
+ // if the first element of the packet is available, the remaining elements
+ // are also available.
+ const size_t count = mFmqResultChannel->availableToRead();
+ std::vector<FmqResultDatum> packet(count + 1);
+ std::memcpy(&packet.front(), &datum, sizeof(datum));
+ success &= mFmqResultChannel->read(packet.data() + 1, count);
+
+ if (!mValid) {
+ return std::nullopt;
+ }
+
+ // ensure packet was successfully received
+ if (!success) {
+ LOG(ERROR) << "Error receiving packet";
+ return std::nullopt;
+ }
+
+ return std::make_optional(std::move(packet));
+}
+
+} // namespace android::hardware::neuralnetworks::V1_2::utils