/*
* Copyright (C) 2011 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 "trace.h"
#include <sys/uio.h>
#include <unistd.h>
#include "android-base/stringprintf.h"
#include "art_method-inl.h"
#include "base/casts.h"
#include "base/enums.h"
#include "base/os.h"
#include "base/stl_util.h"
#include "base/systrace.h"
#include "base/time_utils.h"
#include "base/unix_file/fd_file.h"
#include "base/utils.h"
#include "class_linker.h"
#include "common_throws.h"
#include "debugger.h"
#include "dex/descriptors_names.h"
#include "dex/dex_file-inl.h"
#include "entrypoints/quick/quick_entrypoints.h"
#include "gc/scoped_gc_critical_section.h"
#include "instrumentation.h"
#include "mirror/class-inl.h"
#include "mirror/dex_cache-inl.h"
#include "mirror/object-inl.h"
#include "mirror/object_array-inl.h"
#include "nativehelper/scoped_local_ref.h"
#include "scoped_thread_state_change-inl.h"
#include "stack.h"
#include "thread.h"
#include "thread_list.h"
namespace art {
using android::base::StringPrintf;
static constexpr size_t TraceActionBits = MinimumBitsToStore(
static_cast<size_t>(kTraceMethodActionMask));
static constexpr uint8_t kOpNewMethod = 1U;
static constexpr uint8_t kOpNewThread = 2U;
static constexpr uint8_t kOpTraceSummary = 3U;
class BuildStackTraceVisitor : public StackVisitor {
public:
explicit BuildStackTraceVisitor(Thread* thread)
: StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
method_trace_(Trace::AllocStackTrace()) {}
bool VisitFrame() REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* m = GetMethod();
// Ignore runtime frames (in particular callee save).
if (!m->IsRuntimeMethod()) {
method_trace_->push_back(m);
}
return true;
}
// Returns a stack trace where the topmost frame corresponds with the first element of the vector.
std::vector<ArtMethod*>* GetStackTrace() const {
return method_trace_;
}
private:
std::vector<ArtMethod*>* const method_trace_;
DISALLOW_COPY_AND_ASSIGN(BuildStackTraceVisitor);
};
static const char kTraceTokenChar = '*';
static const uint16_t kTraceHeaderLength = 32;
static const uint32_t kTraceMagicValue = 0x574f4c53;
static const uint16_t kTraceVersionSingleClock = 2;
static const uint16_t kTraceVersionDualClock = 3;
static const uint16_t kTraceRecordSizeSingleClock = 10; // using v2
static const uint16_t kTraceRecordSizeDualClock = 14; // using v3 with two timestamps
TraceClockSource Trace::default_clock_source_ = kDefaultTraceClockSource;
Trace* volatile Trace::the_trace_ = nullptr;
pthread_t Trace::sampling_pthread_ = 0U;
std::unique_ptr<std::vector<ArtMethod*>> Trace::temp_stack_trace_;
// The key identifying the tracer to update instrumentation.
static constexpr const char* kTracerInstrumentationKey = "Tracer";
static TraceAction DecodeTraceAction(uint32_t tmid) {
return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
}
ArtMethod* Trace::DecodeTraceMethod(uint32_t tmid) {
MutexLock mu(Thread::Current(), *unique_methods_lock_);
return unique_methods_[tmid >> TraceActionBits];
}
uint32_t Trace::EncodeTraceMethod(ArtMethod* method) {
MutexLock mu(Thread::Current(), *unique_methods_lock_);
uint32_t idx;
auto it = art_method_id_map_.find(method);
if (it != art_method_id_map_.end()) {
idx = it->second;
} else {
unique_methods_.push_back(method);
idx = unique_methods_.size() - 1;
art_method_id_map_.emplace(method, idx);
}
DCHECK_LT(idx, unique_methods_.size());
DCHECK_EQ(unique_methods_[idx], method);
return idx;
}
uint32_t Trace::EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action) {
uint32_t tmid = (EncodeTraceMethod(method) << TraceActionBits) | action;
DCHECK_EQ(method, DecodeTraceMethod(tmid));
return tmid;
}
std::vector<ArtMethod*>* Trace::AllocStackTrace() {
return (temp_stack_trace_.get() != nullptr) ? temp_stack_trace_.release() :
new std::vector<ArtMethod*>();
}
void Trace::FreeStackTrace(std::vector<ArtMethod*>* stack_trace) {
stack_trace->clear();
temp_stack_trace_.reset(stack_trace);
}
void Trace::SetDefaultClockSource(TraceClockSource clock_source) {
#if defined(__linux__)
default_clock_source_ = clock_source;
#else
if (clock_source != TraceClockSource::kWall) {
LOG(WARNING) << "Ignoring tracing request to use CPU time.";
}
#endif
}
static uint16_t GetTraceVersion(TraceClockSource clock_source) {
return (clock_source == TraceClockSource::kDual) ? kTraceVersionDualClock
: kTraceVersionSingleClock;
}
static uint16_t GetRecordSize(TraceClockSource clock_source) {
return (clock_source == TraceClockSource::kDual) ? kTraceRecordSizeDualClock
: kTraceRecordSizeSingleClock;
}
bool Trace::UseThreadCpuClock() {
return (clock_source_ == TraceClockSource::kThreadCpu) ||
(clock_source_ == TraceClockSource::kDual);
}
bool Trace::UseWallClock() {
return (clock_source_ == TraceClockSource::kWall) ||
(clock_source_ == TraceClockSource::kDual);
}
void Trace::MeasureClockOverhead() {
if (UseThreadCpuClock()) {
Thread::Current()->GetCpuMicroTime();
}
if (UseWallClock()) {
MicroTime();
}
}
// Compute an average time taken to measure clocks.
uint32_t Trace::GetClockOverheadNanoSeconds() {
Thread* self = Thread::Current();
uint64_t start = self->GetCpuMicroTime();
for (int i = 4000; i > 0; i--) {
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
}
uint64_t elapsed_us = self->GetCpuMicroTime() - start;
return static_cast<uint32_t>(elapsed_us / 32);
}
// TODO: put this somewhere with the big-endian equivalent used by JDWP.
static void Append2LE(uint8_t* buf, uint16_t val) {
*buf++ = static_cast<uint8_t>(val);
*buf++ = static_cast<uint8_t>(val >> 8);
}
// TODO: put this somewhere with the big-endian equivalent used by JDWP.
static void Append4LE(uint8_t* buf, uint32_t val) {
*buf++ = static_cast<uint8_t>(val);
*buf++ = static_cast<uint8_t>(val >> 8);
*buf++ = static_cast<uint8_t>(val >> 16);
*buf++ = static_cast<uint8_t>(val >> 24);
}
// TODO: put this somewhere with the big-endian equivalent used by JDWP.
static void Append8LE(uint8_t* buf, uint64_t val) {
*buf++ = static_cast<uint8_t>(val);
*buf++ = static_cast<uint8_t>(val >> 8);
*buf++ = static_cast<uint8_t>(val >> 16);
*buf++ = static_cast<uint8_t>(val >> 24);
*buf++ = static_cast<uint8_t>(val >> 32);
*buf++ = static_cast<uint8_t>(val >> 40);
*buf++ = static_cast<uint8_t>(val >> 48);
*buf++ = static_cast<uint8_t>(val >> 56);
}
static void GetSample(Thread* thread, void* arg) REQUIRES_SHARED(Locks::mutator_lock_) {
BuildStackTraceVisitor build_trace_visitor(thread);
build_trace_visitor.WalkStack();
std::vector<ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
Trace* the_trace = reinterpret_cast<Trace*>(arg);
the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
}
static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg ATTRIBUTE_UNUSED) {
thread->SetTraceClockBase(0);
std::vector<ArtMethod*>* stack_trace = thread->GetStackTraceSample();
thread->SetStackTraceSample(nullptr);
delete stack_trace;
}
void Trace::CompareAndUpdateStackTrace(Thread* thread,
std::vector<ArtMethod*>* stack_trace) {
CHECK_EQ(pthread_self(), sampling_pthread_);
std::vector<ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
// Update the thread's stack trace sample.
thread->SetStackTraceSample(stack_trace);
// Read timer clocks to use for all events in this trace.
uint32_t thread_clock_diff = 0;
uint32_t wall_clock_diff = 0;
ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
if (old_stack_trace == nullptr) {
// If there's no previous stack trace sample for this thread, log an entry event for all
// methods in the trace.
for (auto rit = stack_trace->rbegin(); rit != stack_trace->rend(); ++rit) {
LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
thread_clock_diff, wall_clock_diff);
}
} else {
// If there's a previous stack trace for this thread, diff the traces and emit entry and exit
// events accordingly.
auto old_rit = old_stack_trace->rbegin();
auto rit = stack_trace->rbegin();
// Iterate bottom-up over both traces until there's a difference between them.
while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
old_rit++;
rit++;
}
// Iterate top-down over the old trace until the point where they differ, emitting exit events.
for (auto old_it = old_stack_trace->begin(); old_it != old_rit.base(); ++old_it) {
LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
thread_clock_diff, wall_clock_diff);
}
// Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
for (; rit != stack_trace->rend(); ++rit) {
LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
thread_clock_diff, wall_clock_diff);
}
FreeStackTrace(old_stack_trace);
}
}
void* Trace::RunSamplingThread(void* arg) {
Runtime* runtime = Runtime::Current();
intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
CHECK_GE(interval_us, 0);
CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
!runtime->IsAotCompiler()));
while (true) {
usleep(interval_us);
ScopedTrace trace("Profile sampling");
Thread* self = Thread::Current();
Trace* the_trace;
{
MutexLock mu(self, *Locks::trace_lock_);
the_trace = the_trace_;
if (the_trace == nullptr) {
break;
}
}
{
// Avoid a deadlock between a thread doing garbage collection
// and the profile sampling thread, by blocking GC when sampling
// thread stacks (see b/73624630).
gc::ScopedGCCriticalSection gcs(self,
art::gc::kGcCauseInstrumentation,
art::gc::kCollectorTypeInstrumentation);
ScopedSuspendAll ssa(__FUNCTION__);
MutexLock mu(self, *Locks::thread_list_lock_);
runtime->GetThreadList()->ForEach(GetSample, the_trace);
}
}
runtime->DetachCurrentThread();
return nullptr;
}
void Trace::Start(const char* trace_filename, int trace_fd, size_t buffer_size, int flags,
TraceOutputMode output_mode, TraceMode trace_mode, int interval_us) {
Thread* self = Thread::Current();
{
MutexLock mu(self, *Locks::trace_lock_);
if (the_trace_ != nullptr) {
LOG(ERROR) << "Trace already in progress, ignoring this request";
return;
}
}
// Check interval if sampling is enabled
if (trace_mode == TraceMode::kSampling && interval_us <= 0) {
LOG(ERROR) << "Invalid sampling interval: " << interval_us;
ScopedObjectAccess soa(self);
ThrowRuntimeException("Invalid sampling interval: %d", interval_us);
return;
}
// Open trace file if not going directly to ddms.
std::unique_ptr<File> trace_file;
if (output_mode != TraceOutputMode::kDDMS) {
if (trace_fd < 0) {
trace_file.reset(OS::CreateEmptyFileWriteOnly(trace_filename));
} else {
trace_file.reset(new File(trace_fd, "tracefile"));
trace_file->DisableAutoClose();
}
if (trace_file.get() == nullptr) {
PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
ScopedObjectAccess soa(self);
ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
return;
}
}
Runtime* runtime = Runtime::Current();
// Enable count of allocs if specified in the flags.
bool enable_stats = false;
// Create Trace object.
{
// Required since EnableMethodTracing calls ConfigureStubs which visits class linker classes.
gc::ScopedGCCriticalSection gcs(self,
gc::kGcCauseInstrumentation,
gc::kCollectorTypeInstrumentation);
ScopedSuspendAll ssa(__FUNCTION__);
MutexLock mu(self, *Locks::trace_lock_);
if (the_trace_ != nullptr) {
LOG(ERROR) << "Trace already in progress, ignoring this request";
} else {
enable_stats = (flags && kTraceCountAllocs) != 0;
the_trace_ = new Trace(trace_file.release(), trace_filename, buffer_size, flags, output_mode,
trace_mode);
if (trace_mode == TraceMode::kSampling) {
CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
reinterpret_cast<void*>(interval_us)),
"Sampling profiler thread");
the_trace_->interval_us_ = interval_us;
} else {
runtime->GetInstrumentation()->AddListener(the_trace_,
instrumentation::Instrumentation::kMethodEntered |
instrumentation::Instrumentation::kMethodExited |
instrumentation::Instrumentation::kMethodUnwind);
// TODO: In full-PIC mode, we don't need to fully deopt.
runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
}
}
}
// Can't call this when holding the mutator lock.
if (enable_stats) {
runtime->SetStatsEnabled(true);
}
}
void Trace::StopTracing(bool finish_tracing, bool flush_file) {
bool stop_alloc_counting = false;
Runtime* const runtime = Runtime::Current();
Trace* the_trace = nullptr;
Thread* const self = Thread::Current();
pthread_t sampling_pthread = 0U;
{
MutexLock mu(self, *Locks::trace_lock_);
if (the_trace_ == nullptr) {
LOG(ERROR) << "Trace stop requested, but no trace currently running";
} else {
the_trace = the_trace_;
the_trace_ = nullptr;
sampling_pthread = sampling_pthread_;
}
}
// Make sure that we join before we delete the trace since we don't want to have
// the sampling thread access a stale pointer. This finishes since the sampling thread exits when
// the_trace_ is null.
if (sampling_pthread != 0U) {
CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
sampling_pthread_ = 0U;
}
if (the_trace != nullptr) {
stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
if (finish_tracing) {
the_trace->FinishTracing();
}
gc::ScopedGCCriticalSection gcs(self,
gc::kGcCauseInstrumentation,
gc::kCollectorTypeInstrumentation);
ScopedSuspendAll ssa(__FUNCTION__);
if (the_trace->trace_mode_ == TraceMode::kSampling) {
MutexLock mu(self, *Locks::thread_list_lock_);
runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
} else {
runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
runtime->GetInstrumentation()->RemoveListener(
the_trace, instrumentation::Instrumentation::kMethodEntered |
instrumentation::Instrumentation::kMethodExited |
instrumentation::Instrumentation::kMethodUnwind);
}
if (the_trace->trace_file_.get() != nullptr) {
// Do not try to erase, so flush and close explicitly.
if (flush_file) {
if (the_trace->trace_file_->Flush() != 0) {
PLOG(WARNING) << "Could not flush trace file.";
}
} else {
the_trace->trace_file_->MarkUnchecked(); // Do not trigger guard.
}
if (the_trace->trace_file_->Close() != 0) {
PLOG(ERROR) << "Could not close trace file.";
}
}
delete the_trace;
}
if (stop_alloc_counting) {
// Can be racy since SetStatsEnabled is not guarded by any locks.
runtime->SetStatsEnabled(false);
}
}
void Trace::Abort() {
// Do not write anything anymore.
StopTracing(false, false);
}
void Trace::Stop() {
// Finish writing.
StopTracing(true, true);
}
void Trace::Shutdown() {
if (GetMethodTracingMode() != kTracingInactive) {
Stop();
}
}
void Trace::Pause() {
bool stop_alloc_counting = false;
Runtime* runtime = Runtime::Current();
Trace* the_trace = nullptr;
Thread* const self = Thread::Current();
pthread_t sampling_pthread = 0U;
{
MutexLock mu(self, *Locks::trace_lock_);
if (the_trace_ == nullptr) {
LOG(ERROR) << "Trace pause requested, but no trace currently running";
return;
} else {
the_trace = the_trace_;
sampling_pthread = sampling_pthread_;
}
}
if (sampling_pthread != 0U) {
{
MutexLock mu(self, *Locks::trace_lock_);
the_trace_ = nullptr;
}
CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
sampling_pthread_ = 0U;
{
MutexLock mu(self, *Locks::trace_lock_);
the_trace_ = the_trace;
}
}
if (the_trace != nullptr) {
gc::ScopedGCCriticalSection gcs(self,
gc::kGcCauseInstrumentation,
gc::kCollectorTypeInstrumentation);
ScopedSuspendAll ssa(__FUNCTION__);
stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
if (the_trace->trace_mode_ == TraceMode::kSampling) {
MutexLock mu(self, *Locks::thread_list_lock_);
runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
} else {
runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
runtime->GetInstrumentation()->RemoveListener(
the_trace,
instrumentation::Instrumentation::kMethodEntered |
instrumentation::Instrumentation::kMethodExited |
instrumentation::Instrumentation::kMethodUnwind);
}
}
if (stop_alloc_counting) {
// Can be racy since SetStatsEnabled is not guarded by any locks.
Runtime::Current()->SetStatsEnabled(false);
}
}
void Trace::Resume() {
Thread* self = Thread::Current();
Trace* the_trace;
{
MutexLock mu(self, *Locks::trace_lock_);
if (the_trace_ == nullptr) {
LOG(ERROR) << "No trace to resume (or sampling mode), ignoring this request";
return;
}
the_trace = the_trace_;
}
Runtime* runtime = Runtime::Current();
// Enable count of allocs if specified in the flags.
bool enable_stats = (the_trace->flags_ && kTraceCountAllocs) != 0;
{
gc::ScopedGCCriticalSection gcs(self,
gc::kGcCauseInstrumentation,
gc::kCollectorTypeInstrumentation);
ScopedSuspendAll ssa(__FUNCTION__);
// Reenable.
if (the_trace->trace_mode_ == TraceMode::kSampling) {
CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
reinterpret_cast<void*>(the_trace->interval_us_)), "Sampling profiler thread");
} else {
runtime->GetInstrumentation()->AddListener(the_trace,
instrumentation::Instrumentation::kMethodEntered |
instrumentation::Instrumentation::kMethodExited |
instrumentation::Instrumentation::kMethodUnwind);
// TODO: In full-PIC mode, we don't need to fully deopt.
runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
}
}
// Can't call this when holding the mutator lock.
if (enable_stats) {
runtime->SetStatsEnabled(true);
}
}
TracingMode Trace::GetMethodTracingMode() {
MutexLock mu(Thread::Current(), *Locks::trace_lock_);
if (the_trace_ == nullptr) {
return kTracingInactive;
} else {
switch (the_trace_->trace_mode_) {
case TraceMode::kSampling:
return kSampleProfilingActive;
case TraceMode::kMethodTracing:
return kMethodTracingActive;
}
LOG(FATAL) << "Unreachable";
UNREACHABLE();
}
}
static constexpr size_t kMinBufSize = 18U; // Trace header is up to 18B.
Trace::Trace(File* trace_file, const char* trace_name, size_t buffer_size, int flags,
TraceOutputMode output_mode, TraceMode trace_mode)
: trace_file_(trace_file),
buf_(new uint8_t[std::max(kMinBufSize, buffer_size)]()),
flags_(flags), trace_output_mode_(output_mode), trace_mode_(trace_mode),
clock_source_(default_clock_source_),
buffer_size_(std::max(kMinBufSize, buffer_size)),
start_time_(MicroTime()), clock_overhead_ns_(GetClockOverheadNanoSeconds()), cur_offset_(0),
overflow_(false), interval_us_(0), streaming_lock_(nullptr),
unique_methods_lock_(new Mutex("unique methods lock", kTracingUniqueMethodsLock)) {
uint16_t trace_version = GetTraceVersion(clock_source_);
if (output_mode == TraceOutputMode::kStreaming) {
trace_version |= 0xF0U;
}
// Set up the beginning of the trace.
memset(buf_.get(), 0, kTraceHeaderLength);
Append4LE(buf_.get(), kTraceMagicValue);
Append2LE(buf_.get() + 4, trace_version);
Append2LE(buf_.get() + 6, kTraceHeaderLength);
Append8LE(buf_.get() + 8, start_time_);
if (trace_version >= kTraceVersionDualClock) {
uint16_t record_size = GetRecordSize(clock_source_);
Append2LE(buf_.get() + 16, record_size);
}
static_assert(18 <= kMinBufSize, "Minimum buffer size not large enough for trace header");
// Update current offset.
cur_offset_.StoreRelaxed(kTraceHeaderLength);
if (output_mode == TraceOutputMode::kStreaming) {
streaming_file_name_ = trace_name;
streaming_lock_ = new Mutex("tracing lock", LockLevel::kTracingStreamingLock);
seen_threads_.reset(new ThreadIDBitSet());
}
}
Trace::~Trace() {
delete streaming_lock_;
delete unique_methods_lock_;
}
static uint64_t ReadBytes(uint8_t* buf, size_t bytes) {
uint64_t ret = 0;
for (size_t i = 0; i < bytes; ++i) {
ret |= static_cast<uint64_t>(buf[i]) << (i * 8);
}
return ret;
}
void Trace::DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source) {
uint8_t* ptr = buf + kTraceHeaderLength;
uint8_t* end = buf + buf_size;
while (ptr < end) {
uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
ArtMethod* method = DecodeTraceMethod(tmid);
TraceAction action = DecodeTraceAction(tmid);
LOG(INFO) << ArtMethod::PrettyMethod(method) << " " << static_cast<int>(action);
ptr += GetRecordSize(clock_source);
}
}
void Trace::FinishTracing() {
size_t final_offset = 0;
std::set<ArtMethod*> visited_methods;
if (trace_output_mode_ == TraceOutputMode::kStreaming) {
// Clean up.
STLDeleteValues(&seen_methods_);
} else {
final_offset = cur_offset_.LoadRelaxed();
GetVisitedMethods(final_offset, &visited_methods);
}
// Compute elapsed time.
uint64_t elapsed = MicroTime() - start_time_;
std::ostringstream os;
os << StringPrintf("%cversion\n", kTraceTokenChar);
os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
if (UseThreadCpuClock()) {
if (UseWallClock()) {
os << StringPrintf("clock=dual\n");
} else {
os << StringPrintf("clock=thread-cpu\n");
}
} else {
os << StringPrintf("clock=wall\n");
}
os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
if (trace_output_mode_ != TraceOutputMode::kStreaming) {
size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
os << StringPrintf("num-method-calls=%zd\n", num_records);
}
os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns_);
os << StringPrintf("vm=art\n");
os << StringPrintf("pid=%d\n", getpid());
if ((flags_ & kTraceCountAllocs) != 0) {
os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
}
os << StringPrintf("%cthreads\n", kTraceTokenChar);
DumpThreadList(os);
os << StringPrintf("%cmethods\n", kTraceTokenChar);
DumpMethodList(os, visited_methods);
os << StringPrintf("%cend\n", kTraceTokenChar);
std::string header(os.str());
if (trace_output_mode_ == TraceOutputMode::kStreaming) {
MutexLock mu(Thread::Current(), *streaming_lock_); // To serialize writing.
// Write a special token to mark the end of trace records and the start of
// trace summary.
uint8_t buf[7];
Append2LE(buf, 0);
buf[2] = kOpTraceSummary;
Append4LE(buf + 3, static_cast<uint32_t>(header.length()));
WriteToBuf(buf, sizeof(buf));
// Write the trace summary. The summary is identical to the file header when
// the output mode is not streaming (except for methods).
WriteToBuf(reinterpret_cast<const uint8_t*>(header.c_str()), header.length());
// Flush the buffer, which may include some trace records before the summary.
FlushBuf();
} else {
if (trace_file_.get() == nullptr) {
std::vector<uint8_t> data;
data.resize(header.length() + final_offset);
memcpy(data.data(), header.c_str(), header.length());
memcpy(data.data() + header.length(), buf_.get(), final_offset);
Runtime::Current()->GetRuntimeCallbacks()->DdmPublishChunk(CHUNK_TYPE("MPSE"),
ArrayRef<const uint8_t>(data));
const bool kDumpTraceInfo = false;
if (kDumpTraceInfo) {
LOG(INFO) << "Trace sent:\n" << header;
DumpBuf(buf_.get(), final_offset, clock_source_);
}
} else {
if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
!trace_file_->WriteFully(buf_.get(), final_offset)) {
std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
PLOG(ERROR) << detail;
ThrowRuntimeException("%s", detail.c_str());
}
}
}
}
void Trace::DexPcMoved(Thread* thread ATTRIBUTE_UNUSED,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t new_dex_pc) {
// We're not recorded to listen to this kind of event, so complain.
LOG(ERROR) << "Unexpected dex PC event in tracing " << ArtMethod::PrettyMethod(method)
<< " " << new_dex_pc;
}
void Trace::FieldRead(Thread* thread ATTRIBUTE_UNUSED,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t dex_pc,
ArtField* field ATTRIBUTE_UNUSED)
REQUIRES_SHARED(Locks::mutator_lock_) {
// We're not recorded to listen to this kind of event, so complain.
LOG(ERROR) << "Unexpected field read event in tracing " << ArtMethod::PrettyMethod(method)
<< " " << dex_pc;
}
void Trace::FieldWritten(Thread* thread ATTRIBUTE_UNUSED,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t dex_pc,
ArtField* field ATTRIBUTE_UNUSED,
const JValue& field_value ATTRIBUTE_UNUSED)
REQUIRES_SHARED(Locks::mutator_lock_) {
// We're not recorded to listen to this kind of event, so complain.
LOG(ERROR) << "Unexpected field write event in tracing " << ArtMethod::PrettyMethod(method)
<< " " << dex_pc;
}
void Trace::MethodEntered(Thread* thread,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t dex_pc ATTRIBUTE_UNUSED) {
uint32_t thread_clock_diff = 0;
uint32_t wall_clock_diff = 0;
ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
thread_clock_diff, wall_clock_diff);
}
void Trace::MethodExited(Thread* thread,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t dex_pc ATTRIBUTE_UNUSED,
const JValue& return_value ATTRIBUTE_UNUSED) {
uint32_t thread_clock_diff = 0;
uint32_t wall_clock_diff = 0;
ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
thread_clock_diff, wall_clock_diff);
}
void Trace::MethodUnwind(Thread* thread,
Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
ArtMethod* method,
uint32_t dex_pc ATTRIBUTE_UNUSED) {
uint32_t thread_clock_diff = 0;
uint32_t wall_clock_diff = 0;
ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
thread_clock_diff, wall_clock_diff);
}
void Trace::ExceptionThrown(Thread* thread ATTRIBUTE_UNUSED,
Handle<mirror::Throwable> exception_object ATTRIBUTE_UNUSED)
REQUIRES_SHARED(Locks::mutator_lock_) {
LOG(ERROR) << "Unexpected exception thrown event in tracing";
}
void Trace::ExceptionHandled(Thread* thread ATTRIBUTE_UNUSED,
Handle<mirror::Throwable> exception_object ATTRIBUTE_UNUSED)
REQUIRES_SHARED(Locks::mutator_lock_) {
LOG(ERROR) << "Unexpected exception thrown event in tracing";
}
void Trace::Branch(Thread* /*thread*/, ArtMethod* method,
uint32_t /*dex_pc*/, int32_t /*dex_pc_offset*/)
REQUIRES_SHARED(Locks::mutator_lock_) {
LOG(ERROR) << "Unexpected branch event in tracing" << ArtMethod::PrettyMethod(method);
}
void Trace::InvokeVirtualOrInterface(Thread*,
Handle<mirror::Object>,
ArtMethod* method,
uint32_t dex_pc,
ArtMethod*) {
LOG(ERROR) << "Unexpected invoke event in tracing" << ArtMethod::PrettyMethod(method)
<< " " << dex_pc;
}
void Trace::WatchedFramePop(Thread* self ATTRIBUTE_UNUSED,
const ShadowFrame& frame ATTRIBUTE_UNUSED) {
LOG(ERROR) << "Unexpected WatchedFramePop event in tracing";
}
void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
if (UseThreadCpuClock()) {
uint64_t clock_base = thread->GetTraceClockBase();
if (UNLIKELY(clock_base == 0)) {
// First event, record the base time in the map.
uint64_t time = thread->GetCpuMicroTime();
thread->SetTraceClockBase(time);
} else {
*thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
}
}
if (UseWallClock()) {
*wall_clock_diff = MicroTime() - start_time_;
}
}
bool Trace::RegisterMethod(ArtMethod* method) {
mirror::DexCache* dex_cache = method->GetDexCache();
const DexFile* dex_file = dex_cache->GetDexFile();
if (seen_methods_.find(dex_file) == seen_methods_.end()) {
seen_methods_.insert(std::make_pair(dex_file, new DexIndexBitSet()));
}
DexIndexBitSet* bit_set = seen_methods_.find(dex_file)->second;
if (!(*bit_set)[method->GetDexMethodIndex()]) {
bit_set->set(method->GetDexMethodIndex());
return true;
}
return false;
}
bool Trace::RegisterThread(Thread* thread) {
pid_t tid = thread->GetTid();
CHECK_LT(0U, static_cast<uint32_t>(tid));
CHECK_LT(static_cast<uint32_t>(tid), kMaxThreadIdNumber);
if (!(*seen_threads_)[tid]) {
seen_threads_->set(tid);
return true;
}
return false;
}
std::string Trace::GetMethodLine(ArtMethod* method) {
method = method->GetInterfaceMethodIfProxy(kRuntimePointerSize);
return StringPrintf("%#x\t%s\t%s\t%s\t%s\n", (EncodeTraceMethod(method) << TraceActionBits),
PrettyDescriptor(method->GetDeclaringClassDescriptor()).c_str(), method->GetName(),
method->GetSignature().ToString().c_str(), method->GetDeclaringClassSourceFile());
}
void Trace::WriteToBuf(const uint8_t* src, size_t src_size) {
int32_t old_offset = cur_offset_.LoadRelaxed();
int32_t new_offset = old_offset + static_cast<int32_t>(src_size);
if (dchecked_integral_cast<size_t>(new_offset) > buffer_size_) {
// Flush buffer.
if (!trace_file_->WriteFully(buf_.get(), old_offset)) {
PLOG(WARNING) << "Failed streaming a tracing event.";
}
// Check whether the data is too large for the buffer, then write immediately.
if (src_size >= buffer_size_) {
if (!trace_file_->WriteFully(src, src_size)) {
PLOG(WARNING) << "Failed streaming a tracing event.";
}
cur_offset_.StoreRelease(0); // Buffer is empty now.
return;
}
old_offset = 0;
new_offset = static_cast<int32_t>(src_size);
}
cur_offset_.StoreRelease(new_offset);
// Fill in data.
memcpy(buf_.get() + old_offset, src, src_size);
}
void Trace::FlushBuf() {
int32_t offset = cur_offset_.LoadRelaxed();
if (!trace_file_->WriteFully(buf_.get(), offset)) {
PLOG(WARNING) << "Failed flush the remaining data in streaming.";
}
cur_offset_.StoreRelease(0);
}
void Trace::LogMethodTraceEvent(Thread* thread, ArtMethod* method,
instrumentation::Instrumentation::InstrumentationEvent event,
uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
// Ensure we always use the non-obsolete version of the method so that entry/exit events have the
// same pointer value.
method = method->GetNonObsoleteMethod();
// Advance cur_offset_ atomically.
int32_t new_offset;
int32_t old_offset = 0;
// We do a busy loop here trying to acquire the next offset.
if (trace_output_mode_ != TraceOutputMode::kStreaming) {
do {
old_offset = cur_offset_.LoadRelaxed();
new_offset = old_offset + GetRecordSize(clock_source_);
if (static_cast<size_t>(new_offset) > buffer_size_) {
overflow_ = true;
return;
}
} while (!cur_offset_.CompareAndSetWeakSequentiallyConsistent(old_offset, new_offset));
}
TraceAction action = kTraceMethodEnter;
switch (event) {
case instrumentation::Instrumentation::kMethodEntered:
action = kTraceMethodEnter;
break;
case instrumentation::Instrumentation::kMethodExited:
action = kTraceMethodExit;
break;
case instrumentation::Instrumentation::kMethodUnwind:
action = kTraceUnroll;
break;
default:
UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
}
uint32_t method_value = EncodeTraceMethodAndAction(method, action);
// Write data
uint8_t* ptr;
static constexpr size_t kPacketSize = 14U; // The maximum size of data in a packet.
uint8_t stack_buf[kPacketSize]; // Space to store a packet when in streaming mode.
if (trace_output_mode_ == TraceOutputMode::kStreaming) {
ptr = stack_buf;
} else {
ptr = buf_.get() + old_offset;
}
Append2LE(ptr, thread->GetTid());
Append4LE(ptr + 2, method_value);
ptr += 6;
if (UseThreadCpuClock()) {
Append4LE(ptr, thread_clock_diff);
ptr += 4;
}
if (UseWallClock()) {
Append4LE(ptr, wall_clock_diff);
}
static_assert(kPacketSize == 2 + 4 + 4 + 4, "Packet size incorrect.");
if (trace_output_mode_ == TraceOutputMode::kStreaming) {
MutexLock mu(Thread::Current(), *streaming_lock_); // To serialize writing.
if (RegisterMethod(method)) {
// Write a special block with the name.
std::string method_line(GetMethodLine(method));
uint8_t buf2[5];
Append2LE(buf2, 0);
buf2[2] = kOpNewMethod;
Append2LE(buf2 + 3, static_cast<uint16_t>(method_line.length()));
WriteToBuf(buf2, sizeof(buf2));
WriteToBuf(reinterpret_cast<const uint8_t*>(method_line.c_str()), method_line.length());
}
if (RegisterThread(thread)) {
// It might be better to postpone this. Threads might not have received names...
std::string thread_name;
thread->GetThreadName(thread_name);
uint8_t buf2[7];
Append2LE(buf2, 0);
buf2[2] = kOpNewThread;
Append2LE(buf2 + 3, static_cast<uint16_t>(thread->GetTid()));
Append2LE(buf2 + 5, static_cast<uint16_t>(thread_name.length()));
WriteToBuf(buf2, sizeof(buf2));
WriteToBuf(reinterpret_cast<const uint8_t*>(thread_name.c_str()), thread_name.length());
}
WriteToBuf(stack_buf, sizeof(stack_buf));
}
}
void Trace::GetVisitedMethods(size_t buf_size,
std::set<ArtMethod*>* visited_methods) {
uint8_t* ptr = buf_.get() + kTraceHeaderLength;
uint8_t* end = buf_.get() + buf_size;
while (ptr < end) {
uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
ArtMethod* method = DecodeTraceMethod(tmid);
visited_methods->insert(method);
ptr += GetRecordSize(clock_source_);
}
}
void Trace::DumpMethodList(std::ostream& os, const std::set<ArtMethod*>& visited_methods) {
for (const auto& method : visited_methods) {
os << GetMethodLine(method);
}
}
static void DumpThread(Thread* t, void* arg) {
std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
std::string name;
t->GetThreadName(name);
os << t->GetTid() << "\t" << name << "\n";
}
void Trace::DumpThreadList(std::ostream& os) {
Thread* self = Thread::Current();
for (auto it : exited_threads_) {
os << it.first << "\t" << it.second << "\n";
}
Locks::thread_list_lock_->AssertNotHeld(self);
MutexLock mu(self, *Locks::thread_list_lock_);
Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
}
void Trace::StoreExitingThreadInfo(Thread* thread) {
MutexLock mu(thread, *Locks::trace_lock_);
if (the_trace_ != nullptr) {
std::string name;
thread->GetThreadName(name);
// The same thread/tid may be used multiple times. As SafeMap::Put does not allow to override
// a previous mapping, use SafeMap::Overwrite.
the_trace_->exited_threads_.Overwrite(thread->GetTid(), name);
}
}
Trace::TraceOutputMode Trace::GetOutputMode() {
MutexLock mu(Thread::Current(), *Locks::trace_lock_);
CHECK(the_trace_ != nullptr) << "Trace output mode requested, but no trace currently running";
return the_trace_->trace_output_mode_;
}
Trace::TraceMode Trace::GetMode() {
MutexLock mu(Thread::Current(), *Locks::trace_lock_);
CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
return the_trace_->trace_mode_;
}
size_t Trace::GetBufferSize() {
MutexLock mu(Thread::Current(), *Locks::trace_lock_);
CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
return the_trace_->buffer_size_;
}
bool Trace::IsTracingEnabled() {
MutexLock mu(Thread::Current(), *Locks::trace_lock_);
return the_trace_ != nullptr;
}
} // namespace art