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/*
* 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 "LayerTracing"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS
#include "LayerTracing.h"
#include "LayerDataSource.h"
#include "Tracing/tools/LayerTraceGenerator.h"
#include "TransactionTracing.h"
#include <common/trace.h>
#include <log/log.h>
#include <perfetto/tracing.h>
#include <utils/Timers.h>
namespace android {
LayerTracing::LayerTracing() {
mTakeLayersSnapshotProto = [](uint32_t, const OnLayersSnapshotCallback&) {};
LayerDataSource::Initialize(*this);
}
LayerTracing::LayerTracing(std::ostream& outStream) : LayerTracing() {
mOutStream = std::ref(outStream);
}
LayerTracing::~LayerTracing() {
LayerDataSource::UnregisterLayerTracing();
}
void LayerTracing::setTakeLayersSnapshotProtoFunction(
const std::function<void(uint32_t, const OnLayersSnapshotCallback&)>& callback) {
mTakeLayersSnapshotProto = callback;
}
void LayerTracing::setTransactionTracing(TransactionTracing& transactionTracing) {
mTransactionTracing = &transactionTracing;
}
void LayerTracing::onStart(Mode mode, uint32_t flags) {
switch (mode) {
case Mode::MODE_ACTIVE: {
mActiveTracingFlags.store(flags);
mIsActiveTracingStarted.store(true);
ALOGV("Starting active tracing (waiting for initial snapshot)");
// It might take a while before a layers change occurs and a "spontaneous" snapshot is
// taken. Let's manually take a snapshot, so that the trace's first entry will contain
// the current layers state.
auto onLayersSnapshot = [this](perfetto::protos::LayersSnapshotProto&& snapshot) {
addProtoSnapshotToOstream(std::move(snapshot), Mode::MODE_ACTIVE);
};
mTakeLayersSnapshotProto(flags, onLayersSnapshot);
ALOGD("Started active tracing (traced initial snapshot)");
break;
}
case Mode::MODE_GENERATED: {
// This tracing mode processes the buffer of transactions (owned by TransactionTracing),
// generates layers snapshots and writes them to perfetto. This happens every time an
// OnFlush event is received.
ALOGD("Started generated tracing (waiting for OnFlush event to generated layers)");
break;
}
case Mode::MODE_GENERATED_BUGREPORT_ONLY: {
// Same as MODE_GENERATED, but only when the received OnFlush event is due to a
// bugreport being taken. This mode exists because the generated layers trace is very
// large (hundreds of MB), hence we want to include it only in bugreports and not in
// field uploads.
//
// Note that perfetto communicates only whether the OnFlush event is due to a bugreport
// or not, hence we need an additional "bugreport only" tracing mode.
// If perfetto had communicated when the OnFlush is due to a field upload, then we could
// have had a single "generated" tracing mode that would have been a noop in case of
// field uploads.
ALOGD("Started 'generated bugreport only' tracing"
" (waiting for bugreport's OnFlush event to generate layers)");
break;
}
case Mode::MODE_DUMP: {
ALOGD("Started dump tracing");
break;
}
default: {
ALOGE("Started unknown tracing mode (0x%02x)", mode);
}
}
}
void LayerTracing::onFlush(Mode mode, uint32_t flags, bool isBugreport) {
// In "generated" mode process the buffer of transactions (owned by TransactionTracing),
// generate layers snapshots and write them to perfetto.
if (mode != Mode::MODE_GENERATED && mode != Mode::MODE_GENERATED_BUGREPORT_ONLY) {
ALOGD("Skipping layers trace generation (not a 'generated' tracing session)");
return;
}
// In "generated bugreport only" mode skip the layers snapshot generation
// if the perfetto's OnFlush event is not due to a bugreport being taken.
if (mode == Mode::MODE_GENERATED_BUGREPORT_ONLY && !isBugreport) {
ALOGD("Skipping layers trace generation (not a bugreport OnFlush event)");
return;
}
if (!mTransactionTracing) {
ALOGD("Skipping layers trace generation (transactions tracing disabled)");
return;
}
auto transactionTrace = mTransactionTracing->writeToProto();
LayerTraceGenerator{}.generate(transactionTrace, flags, *this);
ALOGD("Flushed generated tracing");
}
void LayerTracing::onStop(Mode mode, uint32_t flags, std::function<void()>&& deferredStopDone) {
switch (mode) {
case Mode::MODE_ACTIVE: {
mIsActiveTracingStarted.store(false);
deferredStopDone();
ALOGD("Stopped active tracing");
break;
}
case Mode::MODE_DUMP: {
auto onLayersSnapshot = [this, deferredStopDone = std::move(deferredStopDone)](
perfetto::protos::LayersSnapshotProto&& snapshot) {
addProtoSnapshotToOstream(std::move(snapshot), Mode::MODE_DUMP);
deferredStopDone();
ALOGD("Stopped dump tracing (written single snapshot)");
};
mTakeLayersSnapshotProto(flags, onLayersSnapshot);
break;
}
default: {
deferredStopDone();
}
}
}
void LayerTracing::addProtoSnapshotToOstream(perfetto::protos::LayersSnapshotProto&& snapshot,
Mode mode) {
SFTRACE_CALL();
if (mOutStream) {
writeSnapshotToStream(std::move(snapshot));
} else {
writeSnapshotToPerfetto(snapshot, mode);
}
}
bool LayerTracing::isActiveTracingStarted() const {
return mIsActiveTracingStarted.load();
}
uint32_t LayerTracing::getActiveTracingFlags() const {
return mActiveTracingFlags.load();
}
bool LayerTracing::isActiveTracingFlagSet(Flag flag) const {
return (mActiveTracingFlags.load() & flag) != 0;
}
perfetto::protos::LayersTraceFileProto LayerTracing::createTraceFileProto() {
perfetto::protos::LayersTraceFileProto fileProto;
fileProto.set_magic_number(
static_cast<uint64_t>(perfetto::protos::LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H)
<< 32 |
perfetto::protos::LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
auto timeOffsetNs = static_cast<uint64_t>(systemTime(SYSTEM_TIME_REALTIME) -
systemTime(SYSTEM_TIME_MONOTONIC));
fileProto.set_real_to_elapsed_time_offset_nanos(timeOffsetNs);
return fileProto;
}
void LayerTracing::writeSnapshotToStream(perfetto::protos::LayersSnapshotProto&& snapshot) const {
auto fileProto = createTraceFileProto();
*fileProto.add_entry() = std::move(snapshot);
mOutStream->get() << fileProto.SerializeAsString();
}
void LayerTracing::writeSnapshotToPerfetto(const perfetto::protos::LayersSnapshotProto& snapshot,
Mode srcMode) {
const auto snapshotBytes = snapshot.SerializeAsString();
LayerDataSource::Trace([&](LayerDataSource::TraceContext context) {
auto dstMode = context.GetCustomTlsState()->mMode;
if (srcMode == Mode::MODE_GENERATED) {
// Layers snapshots produced by LayerTraceGenerator have srcMode == MODE_GENERATED
// and should be written to tracing sessions with MODE_GENERATED
// or MODE_GENERATED_BUGREPORT_ONLY.
if (dstMode != Mode::MODE_GENERATED && dstMode != Mode::MODE_GENERATED_BUGREPORT_ONLY) {
return;
}
} else if (srcMode != dstMode) {
return;
}
if (!checkAndUpdateLastVsyncIdWrittenToPerfetto(srcMode, snapshot.vsync_id())) {
return;
}
{
auto packet = context.NewTracePacket();
packet->set_timestamp(static_cast<uint64_t>(snapshot.elapsed_realtime_nanos()));
packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
auto* snapshotProto = packet->set_surfaceflinger_layers_snapshot();
snapshotProto->AppendRawProtoBytes(snapshotBytes.data(), snapshotBytes.size());
}
{
// TODO (b/162206162): remove empty packet when perfetto bug is fixed.
// It is currently needed in order not to lose the last trace entry.
context.NewTracePacket();
}
});
}
bool LayerTracing::checkAndUpdateLastVsyncIdWrittenToPerfetto(Mode mode, std::int64_t vsyncId) {
// In some situations (e.g. two bugreports taken shortly one after the other) the generated
// sequence of layers snapshots might overlap. Here we check the snapshot's vsyncid to make
// sure that in generated tracing mode a given snapshot is written only once to perfetto.
if (mode != Mode::MODE_GENERATED && mode != Mode::MODE_GENERATED_BUGREPORT_ONLY) {
return true;
}
auto lastVsyncId = mLastVsyncIdWrittenToPerfetto.load();
while (lastVsyncId < vsyncId) {
if (mLastVsyncIdWrittenToPerfetto.compare_exchange_strong(lastVsyncId, vsyncId)) {
return true;
}
}
return false;
}
} // namespace android
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