/*
* 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.
*/
#ifndef ART_RUNTIME_TRACE_H_
#define ART_RUNTIME_TRACE_H_
#include <bitset>
#include <map>
#include <memory>
#include <ostream>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>
#include "base/atomic.h"
#include "base/locks.h"
#include "base/macros.h"
#include "base/os.h"
#include "base/safe_map.h"
#include "instrumentation.h"
#include "runtime_globals.h"
namespace unix_file {
class FdFile;
} // namespace unix_file
namespace art {
class ArtField;
class ArtMethod;
class DexFile;
class LOCKABLE Mutex;
class ShadowFrame;
class Thread;
using DexIndexBitSet = std::bitset<65536>;
constexpr size_t kMaxThreadIdNumber = kIsTargetBuild ? 65536U : 1048576U;
using ThreadIDBitSet = std::bitset<kMaxThreadIdNumber>;
enum TracingMode {
kTracingInactive,
kMethodTracingActive, // Trace activity synchronous with method progress.
kSampleProfilingActive, // Trace activity captured by sampling thread.
};
std::ostream& operator<<(std::ostream& os, const TracingMode& rhs);
// File format:
// header
// record 0
// record 1
// ...
//
// Header format:
// u4 magic ('SLOW')
// u2 version
// u2 offset to data
// u8 start date/time in usec
// u2 record size in bytes (version >= 2 only)
// ... padding to 32 bytes
//
// Record format v1:
// u1 thread ID
// u4 method ID | method action
// u4 time delta since start, in usec
//
// Record format v2:
// u2 thread ID
// u4 method ID | method action
// u4 time delta since start, in usec
//
// Record format v3:
// u2 thread ID
// u4 method ID | method action
// u4 time delta since start, in usec
// u4 wall time since start, in usec (when clock == "dual" only)
//
// 32 bits of microseconds is 70 minutes.
//
// All values are stored in little-endian order.
enum TraceAction {
kTraceMethodEnter = 0x00, // method entry
kTraceMethodExit = 0x01, // method exit
kTraceUnroll = 0x02, // method exited by exception unrolling
// 0x03 currently unused
kTraceMethodActionMask = 0x03, // two bits
};
// Class for recording event traces. Trace data is either collected
// synchronously during execution (TracingMode::kMethodTracingActive),
// or by a separate sampling thread (TracingMode::kSampleProfilingActive).
class Trace final : public instrumentation::InstrumentationListener {
public:
enum TraceFlag {
kTraceCountAllocs = 1,
};
enum class TraceOutputMode {
kFile,
kDDMS,
kStreaming
};
enum class TraceMode {
kMethodTracing,
kSampling
};
~Trace();
static void SetDefaultClockSource(TraceClockSource clock_source);
static void Start(const char* trace_filename,
size_t buffer_size,
int flags,
TraceOutputMode output_mode,
TraceMode trace_mode,
int interval_us)
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_,
!Locks::trace_lock_);
static void Start(int trace_fd,
size_t buffer_size,
int flags,
TraceOutputMode output_mode,
TraceMode trace_mode,
int interval_us)
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_,
!Locks::trace_lock_);
static void Start(std::unique_ptr<unix_file::FdFile>&& file,
size_t buffer_size,
int flags,
TraceOutputMode output_mode,
TraceMode trace_mode,
int interval_us)
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_,
!Locks::trace_lock_);
static void StartDDMS(size_t buffer_size,
int flags,
TraceMode trace_mode,
int interval_us)
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_,
!Locks::trace_lock_);
// Stop tracing. This will finish the trace and write it to file/send it via DDMS.
static void Stop()
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::trace_lock_);
// Abort tracing. This will just stop tracing and *not* write/send the collected data.
static void Abort()
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::trace_lock_);
static void Shutdown()
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::trace_lock_);
static TracingMode GetMethodTracingMode() REQUIRES(!Locks::trace_lock_);
bool UseWallClock();
bool UseThreadCpuClock();
void MeasureClockOverhead();
uint32_t GetClockOverheadNanoSeconds();
void CompareAndUpdateStackTrace(Thread* thread, std::vector<ArtMethod*>* stack_trace)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_);
// InstrumentationListener implementation.
void MethodEntered(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t dex_pc)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_)
override;
void MethodExited(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t dex_pc,
const JValue& return_value)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_)
override;
void MethodUnwind(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t dex_pc)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_)
override;
void DexPcMoved(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t new_dex_pc)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_)
override;
void FieldRead(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t dex_pc,
ArtField* field)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_) override;
void FieldWritten(Thread* thread,
Handle<mirror::Object> this_object,
ArtMethod* method,
uint32_t dex_pc,
ArtField* field,
const JValue& field_value)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_) override;
void ExceptionThrown(Thread* thread,
Handle<mirror::Throwable> exception_object)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_) override;
void ExceptionHandled(Thread* thread, Handle<mirror::Throwable> exception_object)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_) override;
void Branch(Thread* thread,
ArtMethod* method,
uint32_t dex_pc,
int32_t dex_pc_offset)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_) override;
void WatchedFramePop(Thread* thread, const ShadowFrame& frame)
REQUIRES_SHARED(Locks::mutator_lock_) override;
// Reuse an old stack trace if it exists, otherwise allocate a new one.
static std::vector<ArtMethod*>* AllocStackTrace();
// Clear and store an old stack trace for later use.
static void FreeStackTrace(std::vector<ArtMethod*>* stack_trace);
// Save id and name of a thread before it exits.
static void StoreExitingThreadInfo(Thread* thread);
static TraceOutputMode GetOutputMode() REQUIRES(!Locks::trace_lock_);
static TraceMode GetMode() REQUIRES(!Locks::trace_lock_);
static size_t GetBufferSize() REQUIRES(!Locks::trace_lock_);
// Used by class linker to prevent class unloading.
static bool IsTracingEnabled() REQUIRES(!Locks::trace_lock_);
private:
Trace(File* trace_file,
size_t buffer_size,
int flags,
TraceOutputMode output_mode,
TraceMode trace_mode);
// The sampling interval in microseconds is passed as an argument.
static void* RunSamplingThread(void* arg) REQUIRES(!Locks::trace_lock_);
static void StopTracing(bool finish_tracing, bool flush_file)
REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::trace_lock_)
// There is an annoying issue with static functions that create a new object and call into
// that object that causes them to not be able to tell that we don't currently hold the lock.
// This causes the negative annotations to incorrectly have a false positive. TODO: Figure out
// how to annotate this.
NO_THREAD_SAFETY_ANALYSIS;
void FinishTracing()
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_);
void ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff);
void LogMethodTraceEvent(Thread* thread, ArtMethod* method,
instrumentation::Instrumentation::InstrumentationEvent event,
uint32_t thread_clock_diff, uint32_t wall_clock_diff)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_, !streaming_lock_);
// Methods to output traced methods and threads.
void GetVisitedMethods(size_t end_offset, std::set<ArtMethod*>* visited_methods)
REQUIRES(!unique_methods_lock_);
void DumpMethodList(std::ostream& os, const std::set<ArtMethod*>& visited_methods)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_);
void DumpThreadList(std::ostream& os) REQUIRES(!Locks::thread_list_lock_);
// Methods to register seen entitites in streaming mode. The methods return true if the entity
// is newly discovered.
bool RegisterMethod(ArtMethod* method)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(streaming_lock_);
bool RegisterThread(Thread* thread)
REQUIRES(streaming_lock_);
// Copy a temporary buffer to the main buffer. Used for streaming. Exposed here for lock
// annotation.
void WriteToBuf(const uint8_t* src, size_t src_size)
REQUIRES(streaming_lock_);
// Flush the main buffer to file. Used for streaming. Exposed here for lock annotation.
void FlushBuf()
REQUIRES(streaming_lock_);
uint32_t EncodeTraceMethod(ArtMethod* method) REQUIRES(!unique_methods_lock_);
uint32_t EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action)
REQUIRES(!unique_methods_lock_);
ArtMethod* DecodeTraceMethod(uint32_t tmid) REQUIRES(!unique_methods_lock_);
std::string GetMethodLine(ArtMethod* method) REQUIRES(!unique_methods_lock_)
REQUIRES_SHARED(Locks::mutator_lock_);
void DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!unique_methods_lock_);
// Singleton instance of the Trace or null when no method tracing is active.
static Trace* volatile the_trace_ GUARDED_BY(Locks::trace_lock_);
// The default profiler clock source.
static TraceClockSource default_clock_source_;
// Sampling thread, non-zero when sampling.
static pthread_t sampling_pthread_;
// Used to remember an unused stack trace to avoid re-allocation during sampling.
static std::unique_ptr<std::vector<ArtMethod*>> temp_stack_trace_;
// File to write trace data out to, null if direct to ddms.
std::unique_ptr<File> trace_file_;
// Buffer to store trace data. In streaming mode, this is protected
// by the streaming_lock_. In non-streaming mode, reserved regions
// are atomically allocated (using cur_offset_) for log entries to
// be written.
std::unique_ptr<uint8_t[]> buf_;
// Flags enabling extra tracing of things such as alloc counts.
const int flags_;
// The kind of output for this tracing.
const TraceOutputMode trace_output_mode_;
// The tracing method.
const TraceMode trace_mode_;
const TraceClockSource clock_source_;
// Size of buf_.
const size_t buffer_size_;
// Time trace was created.
const uint64_t start_time_;
// Clock overhead.
const uint32_t clock_overhead_ns_;
// Offset into buf_. The field is atomic to allow multiple writers
// to concurrently reserve space in the buffer. The newly written
// buffer contents are not read without some other form of thread
// synchronization, such as suspending all potential writers or
// acquiring *streaming_lock_. Reading cur_offset_ is thus never
// used to ensure visibility of any other objects, and all accesses
// are memory_order_relaxed.
//
// All accesses to buf_ in streaming mode occur whilst holding the
// streaming lock. In streaming mode, the buffer may be written out
// so cur_offset_ can move forwards and backwards.
//
// When not in streaming mode, the buf_ writes can come from
// multiple threads when the trace mode is kMethodTracing. When
// trace mode is kSampling, writes only come from the sampling
// thread.
//
// Reads to the buffer happen after the event sources writing to the
// buffer have been shutdown and all stores have completed. The
// stores are made visible in StopTracing() when execution leaves
// the ScopedSuspendAll block.
AtomicInteger cur_offset_;
// Did we overflow the buffer recording traces?
bool overflow_;
// Map of thread ids and names that have already exited.
SafeMap<pid_t, std::string> exited_threads_;
// Sampling profiler sampling interval.
int interval_us_;
// Streaming mode data.
Mutex* streaming_lock_;
std::map<const DexFile*, DexIndexBitSet*> seen_methods_ GUARDED_BY(streaming_lock_);
std::unique_ptr<ThreadIDBitSet> seen_threads_ GUARDED_BY(streaming_lock_);
// Bijective map from ArtMethod* to index.
// Map from ArtMethod* to index in unique_methods_;
Mutex* unique_methods_lock_ ACQUIRED_AFTER(streaming_lock_);
std::unordered_map<ArtMethod*, uint32_t> art_method_id_map_ GUARDED_BY(unique_methods_lock_);
std::vector<ArtMethod*> unique_methods_ GUARDED_BY(unique_methods_lock_);
DISALLOW_COPY_AND_ASSIGN(Trace);
};
} // namespace art
#endif // ART_RUNTIME_TRACE_H_