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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkChromeTracingTracer.h"
#include "SkJSONWriter.h"
#include "SkThreadID.h"
#include "SkTraceEvent.h"
#include "SkOSFile.h"
#include "SkOSPath.h"
#include "SkStream.h"
#include <chrono>
namespace {
/**
* All events have a fixed block of information (TraceEvent), plus variable length payload:
* {TraceEvent} {TraceEventArgs} {Inline Payload}
*/
struct TraceEventArg {
uint8_t fArgType;
const char* fArgName;
uint64_t fArgValue;
};
// These fields are ordered to minimize size due to alignment. Argument types could be packed
// better, but very few events have many arguments, so the net loss is pretty small.
struct TraceEvent {
char fPhase;
uint8_t fNumArgs;
uint32_t fSize;
const char* fName;
// TODO: Merge fID and fClockEnd (never used together)
uint64_t fID;
uint64_t fClockBegin;
uint64_t fClockEnd;
SkThreadID fThreadID;
TraceEvent* next() {
return reinterpret_cast<TraceEvent*>(reinterpret_cast<char*>(this) + fSize);
}
TraceEventArg* args() {
return reinterpret_cast<TraceEventArg*>(this + 1);
}
char* stringTable() {
return reinterpret_cast<char*>(this->args() + fNumArgs);
}
};
}
SkChromeTracingTracer::SkChromeTracingTracer(const char* filename) : fFilename(filename) {
this->createBlock();
}
SkChromeTracingTracer::~SkChromeTracingTracer() {
this->flush();
}
void SkChromeTracingTracer::createBlock() {
fCurBlock.fBlock = BlockPtr(new uint8_t[kBlockSize]);
fCurBlock.fEventsInBlock = 0;
fCurBlockUsed = 0;
}
SkEventTracer::Handle SkChromeTracingTracer::appendEvent(const void* data, size_t size) {
SkASSERT(size > 0 && size <= kBlockSize);
SkAutoMutexAcquire lock(fMutex);
if (fCurBlockUsed + size > kBlockSize) {
fBlocks.push_back(std::move(fCurBlock));
this->createBlock();
}
memcpy(fCurBlock.fBlock.get() + fCurBlockUsed, data, size);
Handle handle = reinterpret_cast<Handle>(fCurBlock.fBlock.get() + fCurBlockUsed);
fCurBlockUsed += size;
fCurBlock.fEventsInBlock++;
return handle;
}
SkEventTracer::Handle SkChromeTracingTracer::addTraceEvent(char phase,
const uint8_t* categoryEnabledFlag,
const char* name,
uint64_t id,
int numArgs,
const char** argNames,
const uint8_t* argTypes,
const uint64_t* argValues,
uint8_t flags) {
// TODO: Respect flags (or assert). INSTANT events encode scope in flags, should be stored
// using "s" key in JSON. COPY flag should be supported or rejected.
// Figure out how much extra storage we need for copied strings
int size = static_cast<int>(sizeof(TraceEvent) + numArgs * sizeof(TraceEventArg));
for (int i = 0; i < numArgs; ++i) {
if (TRACE_VALUE_TYPE_COPY_STRING == argTypes[i]) {
skia::tracing_internals::TraceValueUnion value;
value.as_uint = argValues[i];
size += strlen(value.as_string) + 1;
}
}
size = SkAlign8(size);
SkSTArray<128, uint8_t, true> storage;
uint8_t* storagePtr = storage.push_back_n(size);
TraceEvent* traceEvent = reinterpret_cast<TraceEvent*>(storagePtr);
traceEvent->fPhase = phase;
traceEvent->fNumArgs = numArgs;
traceEvent->fSize = size;
traceEvent->fName = name;
traceEvent->fID = id;
traceEvent->fClockBegin = std::chrono::steady_clock::now().time_since_epoch().count();
traceEvent->fClockEnd = 0;
traceEvent->fThreadID = SkGetThreadID();
TraceEventArg* traceEventArgs = traceEvent->args();
char* stringTableBase = traceEvent->stringTable();
char* stringTable = stringTableBase;
for (int i = 0; i < numArgs; ++i) {
traceEventArgs[i].fArgName = argNames[i];
traceEventArgs[i].fArgType = argTypes[i];
if (TRACE_VALUE_TYPE_COPY_STRING == argTypes[i]) {
// Just write an offset into the arguments array
traceEventArgs[i].fArgValue = stringTable - stringTableBase;
// Copy string into our buffer (and advance)
skia::tracing_internals::TraceValueUnion value;
value.as_uint = argValues[i];
while (*value.as_string) {
*stringTable++ = *value.as_string++;
}
*stringTable++ = 0;
} else {
traceEventArgs[i].fArgValue = argValues[i];
}
}
return this->appendEvent(storagePtr, size);
}
void SkChromeTracingTracer::updateTraceEventDuration(const uint8_t* categoryEnabledFlag,
const char* name,
SkEventTracer::Handle handle) {
// We could probably get away with not locking here, but let's be totally safe.
SkAutoMutexAcquire lock(fMutex);
TraceEvent* traceEvent = reinterpret_cast<TraceEvent*>(handle);
traceEvent->fClockEnd = std::chrono::steady_clock::now().time_since_epoch().count();
}
static void trace_value_to_json(SkJSONWriter* writer, uint64_t argValue, uint8_t argType,
const char* stringTableBase) {
skia::tracing_internals::TraceValueUnion value;
value.as_uint = argValue;
switch (argType) {
case TRACE_VALUE_TYPE_BOOL:
writer->appendBool(value.as_bool);
break;
case TRACE_VALUE_TYPE_UINT:
writer->appendU64(value.as_uint);
break;
case TRACE_VALUE_TYPE_INT:
writer->appendS64(value.as_int);
break;
case TRACE_VALUE_TYPE_DOUBLE:
writer->appendDouble(value.as_double);
break;
case TRACE_VALUE_TYPE_POINTER:
writer->appendPointer(value.as_pointer);
break;
case TRACE_VALUE_TYPE_STRING:
writer->appendString(value.as_string);
break;
case TRACE_VALUE_TYPE_COPY_STRING:
writer->appendString(stringTableBase + value.as_uint);
break;
default:
writer->appendString("<unknown type>");
break;
}
}
namespace {
struct TraceEventSerializationState {
TraceEventSerializationState(uint64_t clockOffset)
: fClockOffset(clockOffset), fNextThreadID(0) {}
int getShortThreadID(SkThreadID id) {
if (int* shortIDPtr = fShortThreadIDMap.find(id)) {
return *shortIDPtr;
}
int shortID = fNextThreadID++;
fShortThreadIDMap.set(id, shortID);
return shortID;
}
uint64_t fClockOffset;
SkTHashMap<uint64_t, const char*> fBaseTypeResolver;
int fNextThreadID;
SkTHashMap<SkThreadID, int> fShortThreadIDMap;
};
}
static void trace_event_to_json(SkJSONWriter* writer, TraceEvent* traceEvent,
TraceEventSerializationState* serializationState) {
// We track the original (creation time) "name" of each currently live object, so we can
// automatically insert "base_name" fields in object snapshot events.
auto baseTypeResolver = &(serializationState->fBaseTypeResolver);
if (TRACE_EVENT_PHASE_CREATE_OBJECT == traceEvent->fPhase) {
SkASSERT(nullptr == baseTypeResolver->find(traceEvent->fID));
baseTypeResolver->set(traceEvent->fID, traceEvent->fName);
} else if (TRACE_EVENT_PHASE_DELETE_OBJECT == traceEvent->fPhase) {
SkASSERT(nullptr != baseTypeResolver->find(traceEvent->fID));
baseTypeResolver->remove(traceEvent->fID);
}
writer->beginObject();
char phaseString[2] = { traceEvent->fPhase, 0 };
writer->appendString("ph", phaseString);
writer->appendString("name", traceEvent->fName);
if (0 != traceEvent->fID) {
// IDs are (almost) always pointers
writer->appendPointer("id", reinterpret_cast<void*>(traceEvent->fID));
}
// Offset timestamps to reduce JSON length, then convert nanoseconds to microseconds
// (standard time unit for tracing JSON files).
uint64_t relativeTimestamp = static_cast<int64_t>(traceEvent->fClockBegin -
serializationState->fClockOffset);
writer->appendDoubleDigits("ts", static_cast<double>(relativeTimestamp) * 1E-3, 3);
if (0 != traceEvent->fClockEnd) {
double dur = static_cast<double>(traceEvent->fClockEnd - traceEvent->fClockBegin) * 1E-3;
writer->appendDoubleDigits("dur", dur, 3);
}
writer->appendS64("tid", serializationState->getShortThreadID(traceEvent->fThreadID));
// Trace events *must* include a process ID, but for internal tools this isn't particularly
// important (and certainly not worth adding a cross-platform API to get it).
writer->appendS32("pid", 0);
if (traceEvent->fNumArgs) {
writer->beginObject("args");
const char* stringTable = traceEvent->stringTable();
bool addedSnapshot = false;
if (TRACE_EVENT_PHASE_SNAPSHOT_OBJECT == traceEvent->fPhase &&
baseTypeResolver->find(traceEvent->fID) &&
0 != strcmp(*baseTypeResolver->find(traceEvent->fID), traceEvent->fName)) {
// Special handling for snapshots where the name differs from creation.
writer->beginObject("snapshot");
writer->appendString("base_type", *baseTypeResolver->find(traceEvent->fID));
addedSnapshot = true;
}
for (int i = 0; i < traceEvent->fNumArgs; ++i) {
const TraceEventArg* arg = traceEvent->args() + i;
// TODO: Skip '#'
writer->appendName(arg->fArgName);
if (arg->fArgName && '#' == arg->fArgName[0]) {
writer->beginObject();
writer->appendName("id_ref");
trace_value_to_json(writer, arg->fArgValue, arg->fArgType, stringTable);
writer->endObject();
} else {
trace_value_to_json(writer, arg->fArgValue, arg->fArgType, stringTable);
}
}
if (addedSnapshot) {
writer->endObject();
}
writer->endObject();
}
writer->endObject();
}
void SkChromeTracingTracer::flush() {
SkAutoMutexAcquire lock(fMutex);
SkString dirname = SkOSPath::Dirname(fFilename.c_str());
if (!dirname.isEmpty() && !sk_exists(dirname.c_str(), kWrite_SkFILE_Flag)) {
if (!sk_mkdir(dirname.c_str())) {
SkDebugf("Failed to create directory.");
}
}
SkFILEWStream fileStream(fFilename.c_str());
SkJSONWriter writer(&fileStream, SkJSONWriter::Mode::kFast);
writer.beginArray();
uint64_t clockOffset = 0;
if (fBlocks.count() > 0) {
clockOffset = reinterpret_cast<TraceEvent*>(fBlocks[0].fBlock.get())->fClockBegin;
} else if (fCurBlock.fEventsInBlock > 0) {
clockOffset = reinterpret_cast<TraceEvent*>(fCurBlock.fBlock.get())->fClockBegin;
}
TraceEventSerializationState serializationState(clockOffset);
auto event_block_to_json = [](SkJSONWriter* writer, const TraceEventBlock& block,
TraceEventSerializationState* serializationState) {
TraceEvent* traceEvent = reinterpret_cast<TraceEvent*>(block.fBlock.get());
for (int i = 0; i < block.fEventsInBlock; ++i) {
trace_event_to_json(writer, traceEvent, serializationState);
traceEvent = traceEvent->next();
}
};
for (int i = 0; i < fBlocks.count(); ++i) {
event_block_to_json(&writer, fBlocks[i], &serializationState);
}
event_block_to_json(&writer, fCurBlock, &serializationState);
writer.endArray();
writer.flush();
fileStream.flush();
}