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/*
* 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 "class_linker.h"
#include "debugger.h"
#include "dex_cache.h"
#include "object_utils.h"
#include "os.h"
#include "runtime_support.h"
#include "thread.h"
namespace art {
static const uint32_t kTraceMethodActionMask = 0x03; // two bits
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
static inline uint32_t TraceMethodId(uint32_t methodValue) {
return (methodValue & ~kTraceMethodActionMask);
}
static inline uint32_t TraceMethodCombine(uint32_t method, uint8_t traceEvent) {
return (method | traceEvent);
}
bool UseThreadCpuClock() {
// TODO: Allow control over which clock is used
return true;
}
bool UseWallClock() {
// TODO: Allow control over which clock is used
return true;
}
void MeasureClockOverhead() {
if (UseThreadCpuClock()) {
ThreadCpuMicroTime();
}
if (UseWallClock()) {
MicroTime();
}
}
uint32_t GetClockOverhead() {
uint64_t start = ThreadCpuMicroTime();
for (int i = 4000; i > 0; i--) {
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
MeasureClockOverhead();
}
uint64_t elapsed = ThreadCpuMicroTime() - start;
return uint32_t (elapsed / 32);
}
void Append2LE(uint8_t* buf, uint16_t val) {
*buf++ = (uint8_t) val;
*buf++ = (uint8_t) (val >> 8);
}
void Append4LE(uint8_t* buf, uint32_t val) {
*buf++ = (uint8_t) val;
*buf++ = (uint8_t) (val >> 8);
*buf++ = (uint8_t) (val >> 16);
*buf++ = (uint8_t) (val >> 24);
}
void Append8LE(uint8_t* buf, uint64_t val) {
*buf++ = (uint8_t) val;
*buf++ = (uint8_t) (val >> 8);
*buf++ = (uint8_t) (val >> 16);
*buf++ = (uint8_t) (val >> 24);
*buf++ = (uint8_t) (val >> 32);
*buf++ = (uint8_t) (val >> 40);
*buf++ = (uint8_t) (val >> 48);
*buf++ = (uint8_t) (val >> 56);
}
#if defined(__arm__)
static bool InstallStubsClassVisitor(Class* klass, void* trace_stub) {
Trace* tracer = Runtime::Current()->GetTracer();
for (size_t i = 0; i < klass->NumDirectMethods(); i++) {
Method* method = klass->GetDirectMethod(i);
if (method->GetCode() != trace_stub) {
tracer->SaveAndUpdateCode(method, trace_stub);
}
}
for (size_t i = 0; i < klass->NumVirtualMethods(); i++) {
Method* method = klass->GetVirtualMethod(i);
if (method->GetCode() != trace_stub) {
tracer->SaveAndUpdateCode(method, trace_stub);
}
}
return true;
}
static bool UninstallStubsClassVisitor(Class* klass, void* trace_stub) {
Trace* tracer = Runtime::Current()->GetTracer();
for (size_t i = 0; i < klass->NumDirectMethods(); i++) {
Method* method = klass->GetDirectMethod(i);
if (tracer->GetSavedCodeFromMap(method) != NULL) {
tracer->ResetSavedCode(method);
}
}
for (size_t i = 0; i < klass->NumVirtualMethods(); i++) {
Method* method = klass->GetVirtualMethod(i);
if (tracer->GetSavedCodeFromMap(method) != NULL) {
tracer->ResetSavedCode(method);
}
}
return true;
}
static void TraceRestoreStack(Thread* t, void*) {
uintptr_t trace_exit = reinterpret_cast<uintptr_t>(art_trace_exit_from_code);
Frame frame = t->GetTopOfStack();
if (frame.GetSP() != 0) {
for ( ; frame.GetMethod() != 0; frame.Next()) {
if (t->IsTraceStackEmpty()) {
break;
}
uintptr_t pc = frame.GetReturnPC();
Method* method = frame.GetMethod();
if (trace_exit == pc) {
TraceStackFrame trace_frame = t->PopTraceStackFrame();
frame.SetReturnPC(trace_frame.return_pc_);
CHECK(method == trace_frame.method_);
}
}
}
}
#endif
void Trace::AddSavedCodeToMap(const Method* method, const void* code) {
saved_code_map_.insert(std::make_pair(method, code));
}
void Trace::RemoveSavedCodeFromMap(const Method* method) {
saved_code_map_.erase(method);
}
const void* Trace::GetSavedCodeFromMap(const Method* method) {
typedef std::map<const Method*, const void*>::const_iterator It; // TODO: C++0x auto
It it = saved_code_map_.find(method);
if (it == saved_code_map_.end()) {
return NULL;
} else {
return it->second;
}
}
void Trace::SaveAndUpdateCode(Method* method, const void* new_code) {
CHECK(GetSavedCodeFromMap(method) == NULL);
AddSavedCodeToMap(method, method->GetCode());
method->SetCode(new_code);
}
void Trace::ResetSavedCode(Method* method) {
CHECK(GetSavedCodeFromMap(method) != NULL);
method->SetCode(GetSavedCodeFromMap(method));
RemoveSavedCodeFromMap(method);
}
void Trace::Start(const char* trace_filename, int trace_fd, int buffer_size, int flags, bool direct_to_ddms) {
if (Runtime::Current()->IsMethodTracingActive()) {
LOG(INFO) << "Trace already in progress, ignoring this request";
return;
}
ScopedThreadStateChange tsc(Thread::Current(), Thread::kRunnable);
Runtime::Current()->GetThreadList()->SuspendAll(false);
// Open trace file if not going directly to ddms.
File* trace_file = NULL;
if (!direct_to_ddms) {
if (trace_fd < 0) {
trace_file = OS::OpenFile(trace_filename, true);
} else {
trace_file = OS::FileFromFd("tracefile", trace_fd);
}
if (trace_file == NULL) {
PLOG(ERROR) << "Unable to open trace file '" << trace_filename;
Thread::Current()->ThrowNewException("Ljava/lang/RuntimeException;",
StringPrintf("Unable to open trace file '%s'", trace_filename).c_str());
Runtime::Current()->GetThreadList()->ResumeAll(false);
return;
}
}
// Create Trace object.
Trace* tracer(new Trace(trace_file, buffer_size));
Runtime::Current()->EnableMethodTracing(tracer);
tracer->BeginTracing();
Runtime::Current()->GetThreadList()->ResumeAll(false);
}
void Trace::Stop() {
if (!Runtime::Current()->IsMethodTracingActive()) {
LOG(INFO) << "Trace stop requested, but no trace currently running";
return;
}
ScopedThreadStateChange tsc(Thread::Current(), Thread::kRunnable);
Runtime::Current()->GetThreadList()->SuspendAll(false);
Runtime::Current()->GetTracer()->FinishTracing();
Runtime::Current()->DisableMethodTracing();
Runtime::Current()->GetThreadList()->ResumeAll(false);
}
void Trace::BeginTracing() {
// Set the start time of tracing.
start_time_ = MicroTime();
// Set trace version and record size.
if (UseThreadCpuClock() && UseWallClock()) {
trace_version_ = kTraceVersionDualClock;
record_size_ = kTraceRecordSizeDualClock;
} else {
trace_version_ = kTraceVersionSingleClock;
record_size_ = kTraceRecordSizeSingleClock;
}
// 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) {
Append2LE(buf_.get() + 16, record_size_);
}
// Update current offset.
cur_offset_ = kTraceHeaderLength;
// Install all method tracing stubs.
InstallStubs();
}
void Trace::FinishTracing() {
// Uninstall all method tracing stubs.
UninstallStubs();
// Compute elapsed time.
uint64_t elapsed = MicroTime() - start_time_;
size_t final_offset = cur_offset_;
uint32_t clock_overhead = GetClockOverhead();
GetVisitedMethods(final_offset);
std::ostringstream os;
os << StringPrintf("%cversion\n", kTraceTokenChar);
os << StringPrintf("%d\n", trace_version_);
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=%llu\n", elapsed);
os << StringPrintf("num-method-calls=%zd\n", (final_offset - kTraceHeaderLength) / record_size_);
os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead);
os << StringPrintf("vm=art\n");
os << StringPrintf("%cthreads\n", kTraceTokenChar);
DumpThreadList(os);
os << StringPrintf("%cmethods\n", kTraceTokenChar);
DumpMethodList(os);
os << StringPrintf("%cend\n", kTraceTokenChar);
std::string header(os.str());
if (trace_file_.get() == NULL) {
struct iovec iov[2];
iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
iov[0].iov_len = header.length();
iov[1].iov_base = buf_.get();
iov[1].iov_len = final_offset;
Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
} else {
if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
!trace_file_->WriteFully(buf_.get(), final_offset)) {
int err = errno;
LOG(ERROR) << "Trace data write failed: " << strerror(err);
Thread::Current()->ThrowNewException("Ljava/lang/RuntimeException;",
StringPrintf("Trace data write failed: %s", strerror(err)).c_str());
}
}
}
void Trace::LogMethodTraceEvent(Thread* self, const Method* method, Trace::TraceEvent event) {
if (thread_clock_base_map_.find(self) == thread_clock_base_map_.end()) {
uint64_t time = ThreadCpuMicroTime();
thread_clock_base_map_.insert(std::make_pair(self, time));
}
// Advance cur_offset_ atomically.
int32_t new_offset;
int32_t old_offset;
do {
old_offset = cur_offset_;
new_offset = old_offset + record_size_;
if (new_offset > buffer_size_) {
overflow_ = true;
return;
}
} while (android_atomic_release_cas(old_offset, new_offset, &cur_offset_) != 0);
uint32_t method_value = TraceMethodCombine(reinterpret_cast<uint32_t>(method), event);
// Write data
uint8_t* ptr = buf_.get() + old_offset;
Append2LE(ptr, self->GetTid());
Append4LE(ptr + 2, method_value);
ptr += 6;
if (UseThreadCpuClock()) {
uint64_t thread_clock_base = thread_clock_base_map_.find(self)->second;
uint32_t thread_clock_diff = ThreadCpuMicroTime() - thread_clock_base;
Append4LE(ptr, thread_clock_diff);
ptr += 4;
}
if (UseWallClock()) {
uint32_t wall_clock_diff = MicroTime() - start_time_;
Append4LE(ptr, wall_clock_diff);
}
}
void Trace::GetVisitedMethods(size_t end_offset) {
uint8_t* ptr = buf_.get() + kTraceHeaderLength;
uint8_t* end = buf_.get() + end_offset;
while (ptr < end) {
uint32_t method_value = ptr[2] | (ptr[3] << 8) | (ptr[4] << 16) | (ptr[5] << 24);
Method* method = reinterpret_cast<Method*>(TraceMethodId(method_value));
visited_methods_.insert(method);
ptr += record_size_;
}
}
void Trace::DumpMethodList(std::ostream& os) {
typedef std::set<const Method*>::const_iterator It; // TODO: C++0x auto
for (It it = visited_methods_.begin(); it != visited_methods_.end(); ++it) {
const Method* method = *it;
MethodHelper mh(method);
os << StringPrintf("%p\t%s\t%s\t%s\t%s\t%d\n", method,
PrettyDescriptor(mh.GetDeclaringClassDescriptor()).c_str(), mh.GetName(),
mh.GetSignature().c_str(), mh.GetDeclaringClassSourceFile(),
mh.GetLineNumFromNativePC(0));
}
}
static void DumpThread(Thread* t, void* arg) {
std::ostream* os = reinterpret_cast<std::ostream*>(arg);
*os << StringPrintf("%d\t%s\n", t->GetTid(), t->GetThreadName()->ToModifiedUtf8().c_str());
}
void Trace::DumpThreadList(std::ostream& os) {
ScopedThreadListLock thread_list_lock;
Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
}
void Trace::InstallStubs() {
#if defined(__arm__)
void* trace_stub = reinterpret_cast<void*>(art_trace_entry_from_code);
Runtime::Current()->GetClassLinker()->VisitClasses(InstallStubsClassVisitor, trace_stub);
#else
UNIMPLEMENTED(WARNING);
#endif
}
void Trace::UninstallStubs() {
#if defined(__arm__)
void* trace_stub = reinterpret_cast<void*>(art_trace_entry_from_code);
Runtime::Current()->GetClassLinker()->VisitClasses(UninstallStubsClassVisitor, trace_stub);
// Restore stacks of all threads
{
ScopedThreadListLock thread_list_lock;
Runtime::Current()->GetThreadList()->ForEach(TraceRestoreStack, NULL);
}
#else
UNIMPLEMENTED(WARNING);
#endif
}
} // namespace art