Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 1 | // Copyright (C) 2019 The Android Open Source Project |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | #include "common/debug.h" |
| 16 | #include "common/expected.h" |
| 17 | #include "perfetto/rx_producer.h" |
| 18 | |
| 19 | #include <android-base/file.h> |
| 20 | #include <android-base/properties.h> |
| 21 | #include <android-base/unique_fd.h> |
| 22 | |
| 23 | #include <iostream> |
| 24 | |
| 25 | #include <sched.h> |
| 26 | #include <sys/types.h> |
| 27 | #include <sys/stat.h> |
| 28 | #include <syscall.h> |
| 29 | #include <fcntl.h> |
| 30 | #include <unistd.h> |
| 31 | |
| 32 | // TODO: move to perfetto code |
| 33 | namespace perfetto { |
| 34 | namespace consumer { |
| 35 | |
| 36 | std::ostream& operator<<(std::ostream& os, State state) { |
| 37 | switch (state) { |
| 38 | case State::kTraceFailed: |
| 39 | os << "kTraceFailed"; |
| 40 | break; |
| 41 | case State::kConnectionError: |
| 42 | os << "kConnectionError"; |
| 43 | break; |
| 44 | case State::kSessionNotFound: |
| 45 | os << "kSessionNotFound"; |
| 46 | break; |
| 47 | case State::kIdle: |
| 48 | os << "kIdle"; |
| 49 | break; |
| 50 | case State::kConnecting: |
| 51 | os << "kConnecting"; |
| 52 | break; |
| 53 | case State::kConfigured: |
| 54 | os << "kConfigured"; |
| 55 | break; |
| 56 | case State::kTracing: |
| 57 | os << "kTracing"; |
| 58 | break; |
| 59 | case State::kTraceEnded: |
| 60 | os << "kTraceEnded"; |
| 61 | break; |
| 62 | default: |
| 63 | os << "(unknown)"; // did someone forget to update this code? |
| 64 | break; |
| 65 | } |
| 66 | return os; |
| 67 | } |
| 68 | |
| 69 | } // namespace consumer |
| 70 | } // namespace perfetto |
| 71 | |
| 72 | namespace iorap::perfetto { |
| 73 | |
| 74 | PerfettoDependencies::Component PerfettoDependencies::CreateComponent() { |
| 75 | // TODO: read from config. |
| 76 | static const uint32_t kTraceDurationMs = |
| 77 | ::android::base::GetUintProperty("iorapd.perfetto.trace_duration_ms", /*default*/5000U); |
| 78 | |
| 79 | static const uint32_t kBufferSize = |
| 80 | ::android::base::GetUintProperty("iorapd.perfetto.buffer_size", /*default*/4096U); |
| 81 | |
| 82 | return fruit::createComponent() |
| 83 | .bind<PerfettoConsumer, PerfettoConsumerImpl>() |
| 84 | .registerProvider([]() /* -> TraceConfig */ { |
| 85 | return CreateConfig(kTraceDurationMs, |
| 86 | /*deferred_start*/true, |
| 87 | kBufferSize); |
| 88 | }); |
| 89 | } |
| 90 | |
| 91 | ::perfetto::protos::TraceConfig PerfettoDependencies::CreateConfig(uint32_t duration_ms, |
| 92 | bool deferred_start, |
| 93 | uint32_t buffer_size) { |
| 94 | ::perfetto::protos::TraceConfig trace_config; |
| 95 | |
| 96 | trace_config.set_duration_ms(duration_ms); |
| 97 | trace_config.add_buffers()->set_size_kb(buffer_size); |
| 98 | trace_config.set_deferred_start(deferred_start); |
| 99 | |
| 100 | auto* ds_config = trace_config.add_data_sources()->mutable_config(); |
| 101 | ds_config->set_name("linux.ftrace"); |
| 102 | ds_config->mutable_ftrace_config()->add_ftrace_events( |
| 103 | "mm_filemap_add_to_page_cache"); |
| 104 | ds_config->mutable_ftrace_config()->add_ftrace_events( |
| 105 | "mm_filemap_delete_from_page_cache"); |
| 106 | ds_config->set_target_buffer(0); |
| 107 | |
| 108 | return trace_config; |
| 109 | } |
| 110 | |
| 111 | // RAII-style wrapper around a perfetto handle that calls Destroy |
| 112 | // in a thread-safe manner. |
| 113 | struct PerfettoConsumerHandle { |
| 114 | private: |
| 115 | std::shared_ptr<PerfettoConsumer> consumer_; |
| 116 | PerfettoConsumer::Handle handle_; |
| 117 | |
| 118 | public: |
| 119 | // Takes over ownership of the 'handle'. |
| 120 | // |
| 121 | // Consumer must not be null. |
| 122 | PerfettoConsumerHandle(std::shared_ptr<PerfettoConsumer> consumer, |
| 123 | PerfettoConsumer::Handle handle) |
| 124 | : consumer_{std::move(consumer)}, |
| 125 | handle_{std::move(handle)} { |
| 126 | DCHECK(consumer_ != nullptr); |
| 127 | } |
| 128 | |
| 129 | std::shared_ptr<PerfettoConsumer> GetConsumer() const { |
| 130 | return consumer_; |
| 131 | } |
| 132 | |
| 133 | PerfettoConsumer::Handle GetHandle() const { |
| 134 | return handle_; |
| 135 | } |
| 136 | |
| 137 | ~PerfettoConsumerHandle() { |
| 138 | LOG(VERBOSE) << "PerfettoConsumerHandle::Destroy(" << handle_ << ")"; |
| 139 | consumer_->Destroy(handle_); |
| 140 | } |
| 141 | |
| 142 | bool operator==(const PerfettoConsumerHandle& other) const { |
| 143 | return handle_ == other.handle_ && consumer_ == other.consumer_; |
| 144 | } |
| 145 | |
| 146 | bool operator!=(const PerfettoConsumerHandle& other) const { |
| 147 | return !(*this == other); |
| 148 | } |
| 149 | }; |
| 150 | |
| 151 | |
| 152 | // Snapshot of a single perfetto OnStateChanged callback. |
| 153 | // |
| 154 | // Operate on the PerfettoConsumer to further change the state. |
| 155 | // |
| 156 | // The Handle is kept 'valid' until all references to the PerfettoConsumerHandle |
| 157 | // are dropped to 0. This ensures the Handle is not destroyed too early. All |
| 158 | // direct usages of 'Handle' must be scoped by the PerfettoConsumerHandle. |
| 159 | struct PerfettoStateChange { |
| 160 | public: |
| 161 | using State = ::perfetto::consumer::State; |
| 162 | using Handle = ::perfetto::consumer::Handle; |
| 163 | |
| 164 | State state; // Never invalid. |
| 165 | std::shared_ptr<PerfettoConsumerHandle> perfetto_consumer_and_handle; // Never null. |
| 166 | |
| 167 | // Safety: Use only within scope of the PerfettoStateChange. |
| 168 | Handle GetHandle() const { |
| 169 | // TODO: it would be even safer to wrap all the calls to the handle inside a class, |
| 170 | // instead of exposing this raw Handle. |
| 171 | return perfetto_consumer_and_handle->GetHandle(); |
| 172 | } |
| 173 | |
| 174 | std::shared_ptr<PerfettoConsumer> GetConsumer() const { |
| 175 | return perfetto_consumer_and_handle->GetConsumer(); |
| 176 | } |
| 177 | }; |
| 178 | |
| 179 | std::ostream& operator<<(std::ostream& os, const PerfettoStateChange& state_change) { |
| 180 | os << "PerfettoStateChange{" << state_change.state << "," |
| 181 | << state_change.GetHandle() << "," |
| 182 | << state_change.GetConsumer().get() << "}"; |
| 183 | return os; |
| 184 | } |
| 185 | |
| 186 | // Once created, this acts as a hot observable, emitting 'PerfettoStateChange' transition items. |
| 187 | // Only the 'state' will vary, the handle and perfetto_consumer are always the same value. |
| 188 | // |
| 189 | // Clients only need to handle the success states in #on_next, all failure states will go to |
| 190 | // #on_error. |
| 191 | // |
| 192 | // Upon reaching the appropriate terminal states, either #on_completed or #on_error is called. |
| 193 | // No future callbacks will then occur, so this object should be subsequently deleted. |
| 194 | // |
| 195 | // The Handle is destroyed automatically after the last item is emitted, so it must only be |
| 196 | // manipulated from the #on_next callbacks. Do not save the Handle and use it at other times. |
| 197 | class StateChangedSubject { |
| 198 | public: |
| 199 | using State = ::perfetto::consumer::State; |
| 200 | using Handle = ::perfetto::consumer::Handle; |
| 201 | |
Yan Wang | b2eceb6 | 2020-04-30 15:48:21 -0700 | [diff] [blame] | 202 | // Static members to solve use-after-free bug. |
| 203 | // The object is accessed from not only perfetto thread, but also iorap |
| 204 | // thread. Use this global map to manage it. |
| 205 | static std::mutex state_subject_mutex_; |
| 206 | static std::unordered_map<Handle, StateChangedSubject*> state_subject_map_; |
| 207 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 208 | StateChangedSubject(const ::perfetto::protos::TraceConfig& trace_config, |
| 209 | rxcpp::subscriber<PerfettoStateChange> destination, |
| 210 | std::shared_ptr<PerfettoConsumer> perfetto_consumer) |
| 211 | : deferred_start(trace_config.deferred_start()), |
| 212 | dest(std::move(destination)), |
| 213 | perfetto_consumer_(std::move(perfetto_consumer)) { |
| 214 | DCHECK(perfetto_consumer_ != nullptr); |
| 215 | } |
| 216 | |
| 217 | private: |
| 218 | struct StateChangedError : public std::runtime_error { |
| 219 | explicit StateChangedError(const std::string& what_arg) : std::runtime_error(what_arg) {} |
| 220 | }; |
| 221 | |
| 222 | std::shared_ptr<PerfettoConsumerHandle> handle_; // non-null after bound_ == true. |
| 223 | std::atomic<bool> bound_{false}; // synchronize-with for BindHandle -> OnStateChanged. |
| 224 | |
| 225 | State last_state{State::kIdle}; |
| 226 | bool deferred_start{false}; |
| 227 | |
| 228 | rxcpp::subscriber<PerfettoStateChange> dest; |
| 229 | std::shared_ptr<PerfettoConsumer> perfetto_consumer_; // This is never null. |
| 230 | |
| 231 | void DcheckBadStateTransition(State state, bool fail_unless = false) const { |
| 232 | DCHECK(fail_unless) << "Invalid state transition to " << state << " from " << last_state; |
| 233 | } |
| 234 | |
| 235 | void DcheckValidStateTransition(State state) { |
| 236 | // State must not be out of range. |
| 237 | DCHECK_GE(state, State::kTraceFailed); |
| 238 | DCHECK_LE(state, State::kTraceEnded); |
| 239 | |
| 240 | // Internal state that should never leak out into public perfetto API: |
| 241 | DCHECK_NE(state, State::kIdle); |
| 242 | // These can only be returned by PollState: |
| 243 | DCHECK_NE(state, State::kSessionNotFound); |
| 244 | |
| 245 | // Validate state transitions as per the perfetto API contract. |
| 246 | // See the 'state diagram' in consumer_api.h |
| 247 | switch (last_state) { |
| 248 | case State::kTraceFailed: // Final and unrecoverable. |
| 249 | // b/122548195: this can transition to 'kConnectionError' if selinux is disabled. |
| 250 | if (state == State::kConnectionError) { |
| 251 | LOG(WARNING) << "b/122548195: kTraceFailed is non-terminal, ignoring."; |
| 252 | // This is a bit awkward: rxcpp will drop the #on_error calls if its more than once. |
| 253 | break; |
| 254 | } |
| 255 | DcheckBadStateTransition(state); |
| 256 | break; |
| 257 | case State::kConnectionError: // Final and unrecoverable. |
| 258 | DcheckBadStateTransition(state); |
| 259 | break; |
| 260 | case State::kSessionNotFound: |
| 261 | DcheckBadStateTransition(state); |
| 262 | break; |
| 263 | case State::kIdle: |
| 264 | // OK: we initialized our own state to idle prior to the first callback. |
| 265 | break; |
| 266 | case State::kConnecting: |
| 267 | switch (state) { |
| 268 | case State::kConfigured: |
| 269 | // kConfigured, if |deferred_start| == true in the trace config. |
| 270 | DcheckBadStateTransition(state, deferred_start); |
| 271 | break; |
| 272 | case State::kTracing: |
| 273 | // kTracing, if |deferred_start| == false. |
| 274 | DcheckBadStateTransition(state, !deferred_start); |
| 275 | break; |
| 276 | case State::kConnectionError: |
| 277 | // An error state, e.g. if cannot reach the traced daemon. |
| 278 | break; |
| 279 | default: |
| 280 | // Unconditionally invalid state transitions from kConnecting to anything else. |
| 281 | DcheckBadStateTransition(state); |
| 282 | } |
| 283 | break; |
| 284 | case State::kConfigured: |
| 285 | DCHECK(deferred_start); |
| 286 | if (state != State::kTracing // OK: this is documented. |
| 287 | && state != State::kTraceFailed) { // Undocumented selinux failure. |
| 288 | // Undocumented, but it appears to go directly from Configured->TraceEnded |
| 289 | // it can also go to kTraceFailed if e.g. there's an selinux violation |
| 290 | // however this appears to be underdocumented. |
| 291 | // b/122607276 #2 |
| 292 | |
| 293 | if (state != State::kTraceEnded) { // b/122607276 #1 |
| 294 | DcheckBadStateTransition(state); |
| 295 | } |
| 296 | } |
| 297 | break; |
| 298 | case State::kTracing: |
| 299 | switch (state) { |
| 300 | case State::kTraceEnded: |
| 301 | break; |
| 302 | case State::kTraceFailed: |
| 303 | break; |
| 304 | default: |
| 305 | DcheckBadStateTransition(state); |
| 306 | } |
| 307 | break; |
| 308 | case State::kTraceEnded: |
| 309 | // Cannot transition from terminal state to another state. |
| 310 | DcheckBadStateTransition(state); |
| 311 | break; |
| 312 | |
| 313 | // default: This list is exhaustive |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | constexpr bool IsTerminalState() const { |
| 318 | switch (last_state) { |
| 319 | case State::kTraceFailed: |
| 320 | case State::kConnectionError: |
| 321 | case State::kTraceEnded: |
| 322 | return true; |
| 323 | default: |
| 324 | return false; |
| 325 | } |
| 326 | } |
| 327 | |
| 328 | // Returns true for non-terminal states (i.e. this callback will be invoked again). |
| 329 | // Returns false otherwise. |
| 330 | bool OnStateChanged(Handle handle, State state) { |
| 331 | using namespace ::perfetto::consumer; |
| 332 | |
| 333 | // Block until 'BoundHandle' is called by the other thread. |
| 334 | while (!bound_.load()) {} // seq_cst acquire. |
| 335 | |
| 336 | std::shared_ptr<PerfettoConsumerHandle> handle_ptr = handle_; |
| 337 | DCHECK(handle_ptr != nullptr); |
| 338 | |
| 339 | DCHECK_EQ(handle_ptr->GetHandle(), handle); |
| 340 | DcheckValidStateTransition(state); |
| 341 | |
| 342 | switch (state) { |
| 343 | // Error states (terminal). |
| 344 | case State::kTraceFailed: |
| 345 | EmitError("kTraceFailed"); |
| 346 | break; |
| 347 | case State::kConnectionError: |
| 348 | EmitError("kConnectionError"); |
| 349 | break; |
| 350 | |
| 351 | // Regular transitions (non-terminal). |
| 352 | case State::kConnecting: |
| 353 | case State::kConfigured: |
| 354 | case State::kTracing: |
| 355 | EmitNext(state); |
| 356 | break; |
| 357 | // Regular transitions (terminal). |
| 358 | case State::kTraceEnded: // XX: do we even need to emit the 'TraceEnded' state? |
| 359 | EmitNext(state); |
| 360 | dest.on_completed(); |
| 361 | break; |
| 362 | default: |
| 363 | DcheckBadStateTransition(state); |
| 364 | } |
| 365 | |
| 366 | bool force_non_terminal = false; |
| 367 | |
| 368 | if (last_state == State::kConfigured && state == State::kConnectionError) { |
| 369 | // b/122548195: this can transition to 'kConnectionError' if selinux is disabled. |
| 370 | force_non_terminal = true; |
| 371 | // This function must 'return true' in this buggy case, otherwise we will |
| 372 | // call the destructor too early and subsequent callbacks will crash. |
| 373 | } |
| 374 | |
| 375 | // Remember the state to validate prior state transitions. |
| 376 | last_state = state; |
| 377 | |
| 378 | // The owner of this class should avoid leaking memory once we reach a terminal state. |
| 379 | return !IsTerminalState() || force_non_terminal; |
| 380 | } |
| 381 | |
| 382 | public: |
| 383 | // Thread safety: Called by main thread, terminates the rx stream. |
| 384 | // When this function is invoked, no calls to this class from other threads can occur. |
| 385 | void OnCreateFailed() { |
| 386 | // returned when an invalid handle is passed to PollState(). |
| 387 | last_state = State::kSessionNotFound; |
| 388 | EmitError("Create returned kInvalidHandle"); |
| 389 | } |
| 390 | |
| 391 | // Thread safety: Called by main thread, this could be concurrent to |
| 392 | // 'CallbackOnStateChanged'. |
| 393 | void BindHandle(const std::shared_ptr<PerfettoConsumerHandle>& handle) { |
| 394 | handle_ = handle; |
| 395 | |
| 396 | // Unblock OnStateChanged. |
| 397 | bound_.store(true); // seq_cst release. |
| 398 | } |
| 399 | |
Yan Wang | b2eceb6 | 2020-04-30 15:48:21 -0700 | [diff] [blame] | 400 | |
| 401 | // Called by libperfetto background thread (same one every time) and iorap |
| 402 | // thread. |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 403 | static void CallbackOnStateChanged(Handle handle, State state, void* callback_arg) { |
| 404 | LOG(VERBOSE) << "CallbackOnStateChanged(handle=" << handle << ",state=" << state |
| 405 | << ",callback_arg=" << callback_arg << ")"; |
| 406 | |
| 407 | // Validate OnStateChanged callback invariants, guaranteed by libperfetto. |
| 408 | DCHECK_NE(handle, ::perfetto::consumer::kInvalidHandle); |
| 409 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 410 | // TODO: the memory ordering guarantees should be explicitly specified in consumer_api.h: |
| 411 | // This isn't specific enough: |
| 412 | // "The callback will be invoked on an internal thread and must not block." |
| 413 | // However looking at the implementation it posts onto a single-thread task runner, |
| 414 | // so this must be the case. |
| 415 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 416 | // This current thread owns 'StateChangedSubject', no other threads must access it. |
| 417 | // Explicit synchronization is not necessary. |
| 418 | |
Yan Wang | b2eceb6 | 2020-04-30 15:48:21 -0700 | [diff] [blame] | 419 | { |
| 420 | std::lock_guard<std::mutex> guard(StateChangedSubject::state_subject_mutex_); |
| 421 | auto it = StateChangedSubject::state_subject_map_.find(handle); |
| 422 | // If the object is already deleted, do nothing. |
| 423 | if (it == StateChangedSubject::state_subject_map_.end()) { |
| 424 | return; |
| 425 | } |
| 426 | |
| 427 | StateChangedSubject* state_subject = it->second; |
| 428 | if (!state_subject->OnStateChanged(handle, state)) { |
| 429 | // Clean up the state tracker when we reach a terminal state. |
| 430 | // This means that no future callbacks will occur anymore. |
| 431 | StateChangedSubject::state_subject_map_.erase(it); |
| 432 | delete state_subject; |
| 433 | } |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 434 | } |
| 435 | } |
| 436 | |
| 437 | private: |
| 438 | void EmitError(const std::string& msg) { |
| 439 | // Sidenote: Exact error class does not matter, rxcpp only lets us access the error |
| 440 | // as a string (rxcpp::util::what). |
| 441 | // |
| 442 | // Either way, the recovery strategy is identical (log then try and restart). |
| 443 | dest.on_error(rxcpp::util::make_error_ptr(StateChangedError{msg})); |
| 444 | } |
| 445 | |
| 446 | void EmitNext(State state) { |
| 447 | if (WOULD_LOG(VERBOSE) && !dest.is_subscribed()) { |
| 448 | // This is purely for logging: #on_next already filters out items after unsubscription. |
| 449 | LOG(VERBOSE) << "StateChangedSubject#EmitNext(" << state << ") - drop due to unsubscribe"; |
| 450 | } |
| 451 | |
| 452 | auto handle_ptr = handle_; |
| 453 | DCHECK(handle_ptr != nullptr); |
| 454 | |
| 455 | // Non-null guarantee for the items emitted into this stream. |
| 456 | PerfettoStateChange state_change{state, handle_ptr}; |
| 457 | dest.on_next(std::move(state_change)); |
| 458 | } |
| 459 | |
| 460 | // TODO: inherit from rx subject and handle #unsubscribe explicitly, instead |
| 461 | // of just being subject-like? |
| 462 | }; |
| 463 | |
Yan Wang | b2eceb6 | 2020-04-30 15:48:21 -0700 | [diff] [blame] | 464 | std::mutex StateChangedSubject::state_subject_mutex_; |
| 465 | std::unordered_map<::perfetto::consumer::Handle, |
| 466 | StateChangedSubject*> StateChangedSubject::state_subject_map_; |
| 467 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 468 | // Note: The states will be emitted on a separate thread, so e.g. #as_blocking() |
| 469 | // needs to be used to avoid dropping everything on the floor. |
| 470 | // |
| 471 | // Important: The #on_error case must be handled explicitly by the observable, |
| 472 | // because the default behavior is to 'throw' which will cause an std::terminate with -fno-except. |
| 473 | static auto /*[observable<State>, shared_ptr<PerfettoConsumerHandle>]*/ |
| 474 | CreatePerfettoStateStream(::perfetto::protos::TraceConfig perfetto_config, |
| 475 | std::shared_ptr<PerfettoConsumer> perfetto_consumer) { |
| 476 | auto obs = rxcpp::observable<>::create<PerfettoStateChange>( |
| 477 | [perfetto_config = std::move(perfetto_config), perfetto_consumer = std::move(perfetto_consumer)] |
| 478 | (rxcpp::subscriber<PerfettoStateChange> subscriber) { |
| 479 | std::unique_ptr<StateChangedSubject> state_subject{ |
| 480 | new StateChangedSubject{perfetto_config, subscriber, perfetto_consumer}}; |
| 481 | |
| 482 | // Perfetto API requires a pointer to a serialized protobuf, it doesn't accept |
| 483 | // the code-generated object. |
| 484 | std::string perfetto_config_str = perfetto_config.SerializeAsString(); |
| 485 | |
| 486 | ::perfetto::consumer::Handle handle = |
| 487 | perfetto_consumer->Create(perfetto_config_str.data(), |
| 488 | perfetto_config_str.size(), |
| 489 | // executes on the same background thread repeatedly. |
| 490 | &StateChangedSubject::CallbackOnStateChanged, |
| 491 | // inter-thread-move |
| 492 | reinterpret_cast<void*>(state_subject.get())); |
| 493 | // perfetto::consumer::Create synchronizes-with OnStateChanged callback, this means |
| 494 | // we don't need to explicitly synchronize state_subject here so long as we don't access |
| 495 | // it on this thread again. |
| 496 | LOG(DEBUG) << "Create Perfetto handle " << handle; |
| 497 | |
| 498 | if (handle == ::perfetto::consumer::kInvalidHandle) { |
| 499 | LOG(ERROR) << "Failed to create Perfetto handle"; |
| 500 | // No callbacks will occur, so our thread still owns the state subject. |
| 501 | state_subject->OnCreateFailed(); |
| 502 | return; |
| 503 | } |
| 504 | |
Yan Wang | b2eceb6 | 2020-04-30 15:48:21 -0700 | [diff] [blame] | 505 | { |
| 506 | std::lock_guard<std::mutex> guard(StateChangedSubject::state_subject_mutex_); |
| 507 | StateChangedSubject::state_subject_map_[handle] = state_subject.get(); |
| 508 | } |
| 509 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 510 | std::shared_ptr<PerfettoConsumerHandle> safe_handle{ |
| 511 | new PerfettoConsumerHandle{perfetto_consumer, handle}}; |
| 512 | |
| 513 | // Share ownership of the Handle with the StateSubject. |
| 514 | // This way we defer calling 'Destroy' until the callback reaches a terminal state |
| 515 | // *and* all users of the stream are done with the handle. |
| 516 | state_subject->BindHandle(safe_handle); |
| 517 | |
| 518 | // state_subject ownership is taken over by OnStateChanged. |
| 519 | // It will also be touched in a separate thread, so we must never access it here again. |
| 520 | state_subject.release(); |
| 521 | |
| 522 | // 'subscriber#add' is actually a call to register an on_unsubscribe listener. |
| 523 | subscriber.add([safe_handle]() { |
| 524 | LOG(VERBOSE) << "PerfettoStateChange#unsubscribe"; |
| 525 | |
| 526 | // Release our ref-count to the handle. |
| 527 | // safe_handle.reset(); // This happens implicitly. |
| 528 | |
| 529 | // TODO: I think this won't handle the case where we need to shut down early. |
| 530 | // Need to use the explicit kShutdown for that? |
| 531 | }); |
| 532 | |
| 533 | // TODO: this would be an excellent place to shuffle the perfetto config protobuf |
| 534 | // into a global debug state for dumpsys. |
| 535 | }); |
| 536 | |
| 537 | return obs; |
| 538 | } |
| 539 | |
| 540 | template <typename T> |
| 541 | bool BinaryWireProtobuf<T>::WriteFullyToFile(const std::string& path, |
| 542 | bool follow_symlinks) const { |
| 543 | // TODO: it would be great if android::base had a string_view overload to avoid copying |
| 544 | // data into an std::string. |
| 545 | |
| 546 | // u g o |
| 547 | // rw-rw---- |
| 548 | // |
| 549 | // Protobufs can be read/written but not executed. |
| 550 | static constexpr const mode_t kMode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP; |
| 551 | |
| 552 | int flags = |
| 553 | O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_BINARY | (follow_symlinks ? 0 : O_NOFOLLOW); |
| 554 | android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), flags, kMode))); |
| 555 | |
| 556 | if (fd == -1) { |
| 557 | PLOG(ERROR) << "BinaryWireProtobuf::WriteFullyToFile open failed"; |
| 558 | return false; |
| 559 | } |
| 560 | |
| 561 | if (!::android::base::WriteFully(fd, data_.data(), size())) { |
| 562 | PLOG(ERROR) << "BinaryWireProtobuf::WriteFullyToFile write failed"; |
| 563 | return CleanUpAfterFailedWrite(path); |
| 564 | } |
| 565 | |
| 566 | return true; |
| 567 | } |
| 568 | |
| 569 | template <typename T> |
| 570 | bool BinaryWireProtobuf<T>::CleanUpAfterFailedWrite(const std::string& path) { |
| 571 | // Something went wrong. Let's not leave a corrupt file lying around. |
| 572 | int saved_errno = errno; |
| 573 | unlink(path.c_str()); |
| 574 | errno = saved_errno; |
| 575 | return false; |
| 576 | } |
| 577 | |
| 578 | template <typename T> |
| 579 | bool BinaryWireProtobuf<T>::WriteStringToFd(int fd) const { |
| 580 | const char* p = reinterpret_cast<const char*>(data_.data()); |
| 581 | size_t left = size(); |
| 582 | while (left > 0) { |
| 583 | ssize_t n = TEMP_FAILURE_RETRY(write(fd, p, left)); |
| 584 | if (n == -1) { |
| 585 | return false; |
| 586 | } |
| 587 | p += n; |
| 588 | left -= n; |
| 589 | } |
| 590 | return true; |
| 591 | } |
| 592 | |
Igor Murashkin | c86d0d0 | 2019-02-22 14:20:42 -0800 | [diff] [blame] | 593 | template <typename T> |
| 594 | std::optional<BinaryWireProtobuf<T>> BinaryWireProtobuf<T>::ReadFullyFromFile( |
| 595 | const std::string& path, |
| 596 | bool follow_symlinks) { |
| 597 | std::vector<std::byte> data; |
| 598 | |
| 599 | int flags = O_RDONLY | O_CLOEXEC | O_BINARY | (follow_symlinks ? 0 : O_NOFOLLOW); |
| 600 | android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), flags))); |
| 601 | if (fd == -1) { |
| 602 | return std::nullopt; |
| 603 | } |
| 604 | |
| 605 | if (ReadFdToString(fd.get(), /*out*/&data)) { |
| 606 | return BinaryWireProtobuf<T>{std::move(data)}; |
| 607 | } else { |
| 608 | return std::nullopt; |
| 609 | } |
| 610 | } |
| 611 | |
| 612 | template <typename T> |
Igor Murashkin | 5e21698 | 2019-10-17 14:11:44 -0700 | [diff] [blame] | 613 | bool BinaryWireProtobuf<T>::operator==(const BinaryWireProtobuf<T>& other) const { |
| 614 | if (data_.size() != other.data_.size()) { |
| 615 | return false; |
| 616 | } |
| 617 | return std::equal(data_.begin(), data_.end(), other.data_.begin()); |
| 618 | } |
| 619 | |
| 620 | template <typename T> |
Igor Murashkin | c86d0d0 | 2019-02-22 14:20:42 -0800 | [diff] [blame] | 621 | bool BinaryWireProtobuf<T>::ReadFdToString(int fd, /*out*/std::vector<std::byte>* content) { |
| 622 | DCHECK(content != nullptr); |
| 623 | |
| 624 | content->clear(); |
| 625 | |
| 626 | struct stat sb; |
| 627 | if (fstat(fd, /*out*/&sb) != -1 && sb.st_size > 0) { |
| 628 | content->reserve(sb.st_size); |
| 629 | } |
| 630 | |
| 631 | char buf[BUFSIZ]; |
| 632 | auto it = content->begin(); |
| 633 | ssize_t n; |
| 634 | while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], sizeof(buf)))) > 0) { |
| 635 | content->insert(it, |
| 636 | reinterpret_cast<std::byte*>(&buf[0]), |
| 637 | reinterpret_cast<std::byte*>(&buf[n])); |
| 638 | |
| 639 | std::advance(/*inout*/it, static_cast<size_t>(n)); |
| 640 | |
| 641 | static_assert(sizeof(char) == sizeof(std::byte), "sanity check for reinterpret cast"); |
| 642 | } |
| 643 | return (n == 0) ? true : false; |
| 644 | } |
| 645 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 646 | // explicit template instantiation. |
| 647 | template struct BinaryWireProtobuf<::google::protobuf::MessageLite>; |
| 648 | // TODO: refactor this not to need the template instantiation. |
| 649 | |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 650 | // Copy of the 2.6.18 kernel header (linux/ioprio.h) |
| 651 | |
| 652 | #define IOPRIO_WHO_PROCESS (1) |
| 653 | #define IOPRIO_CLASS_IDLE (3) |
| 654 | |
| 655 | #define IOPRIO_BITS (16) |
| 656 | #define IOPRIO_CLASS_SHIFT (13) |
| 657 | #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) |
| 658 | |
| 659 | #define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT) |
| 660 | #define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK) |
| 661 | #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data) |
Igor Murashkin | b250cd8 | 2019-01-09 11:33:52 -0800 | [diff] [blame] | 662 | |
| 663 | static int ioprio_get(int which, int who) { |
| 664 | return syscall(SYS_ioprio_get, which, who); |
| 665 | } |
| 666 | |
| 667 | static int ioprio_set(int which, int who, int ioprio) { |
| 668 | return syscall(SYS_ioprio_set, which, who, ioprio); |
| 669 | } |
| 670 | |
| 671 | // An rx Coordination, which will cause a new thread to spawn for each new Worker. |
| 672 | // |
| 673 | // Idle-class priority is set for the CPU and IO priorities on the new thread. |
| 674 | rxcpp::observe_on_one_worker ObserveOnNewIoThread() { |
| 675 | // IO thread factory for idle-priority threads. |
| 676 | // Both the CPU scheduler and the IO scheduler are set to idle. |
| 677 | // |
| 678 | // Use this when needing to schedule disk access from a normal-priority thread onto a |
| 679 | // very low priority thread, but not so low that we need to use a BackgroundJobScheduler. |
| 680 | struct io_thread_factory { |
| 681 | std::thread operator()(std::function<void()> start) const { |
| 682 | return std::thread{ |
| 683 | [start=std::move(start)]() { |
| 684 | // Set IO priority to idle. |
| 685 | do { |
| 686 | int value = ioprio_get(IOPRIO_WHO_PROCESS, /*pid*/0); |
| 687 | if (value == -1) { |
| 688 | PLOG(ERROR) << "io_thread_factory failed ioprio_get"; |
| 689 | break; // Can't set the ioprio, we don't know what data to use. |
| 690 | } |
| 691 | |
| 692 | int data = IOPRIO_PRIO_DATA(value); // priority level |
| 693 | // This appears to be '4' in practice. We may want to raise to |
| 694 | // be the highest-priority within the idle class. |
| 695 | |
| 696 | // idle scheduling class. only access disk when nobody else needs disk. |
| 697 | int res = ioprio_set(IOPRIO_WHO_PROCESS, |
| 698 | /*pid*/0, |
| 699 | IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, data)); |
| 700 | if (res < 0) { |
| 701 | PLOG(ERROR) << "io_thread_factory failed ioprio_set"; |
| 702 | break; |
| 703 | } |
| 704 | |
| 705 | // Changing the IO priority only has any effect with cfq scheduler: |
| 706 | // $> cat /sys/block/sda/queue/scheduler |
| 707 | LOG(VERBOSE) << "ioprio_set(WHO_PROCESS, class=IDLE, data=" << data << ")"; |
| 708 | } while (false); |
| 709 | |
| 710 | // Set CPU priority to idle. |
| 711 | do { |
| 712 | struct sched_param param{}; |
| 713 | param.sched_priority = 0; // Required to be statically 0 when used with SCHED_IDLE. |
| 714 | |
| 715 | if (sched_setscheduler(/*pid*/0, // current thread, |
| 716 | SCHED_IDLE, |
| 717 | /*in*/¶m) != 0) { |
| 718 | PLOG(ERROR) << "io_thread_factory failed sched_setscheduler"; |
| 719 | break; |
| 720 | } |
| 721 | |
| 722 | LOG(VERBOSE) << "sched_setscheduler(self, IDLE)"; |
| 723 | } while (false); |
| 724 | |
| 725 | // XX: if changing the scheduling is too aggressive (i.e. it causes starvation), |
| 726 | // we may want to stick with the default class and change the nice (priority) levels |
| 727 | // to the minimum. |
| 728 | |
| 729 | // TODO: future work, maybe use cgroups configuration file instead? |
| 730 | |
| 731 | // Call the rxcpp-supplied code. |
| 732 | start(); |
| 733 | } |
| 734 | }; |
| 735 | } |
| 736 | }; |
| 737 | |
| 738 | static rxcpp::schedulers::scheduler thread_scheduler = |
| 739 | rxcpp::schedulers::make_new_thread(io_thread_factory{}); |
| 740 | |
| 741 | static rxcpp::observe_on_one_worker observe_on_io_thread{thread_scheduler}; |
| 742 | |
| 743 | return observe_on_io_thread; |
| 744 | } |
| 745 | |
| 746 | static auto/*observable<PerfettoTraceProto>*/ |
| 747 | CreatePerfettoStream(rxcpp::observable<PerfettoStreamCommand> input, |
| 748 | std::shared_ptr<PerfettoConsumer> perfetto_consumer, |
| 749 | const ::perfetto::protos::TraceConfig& trace_config) { |
| 750 | // XX: should I also take a scheduler for input here??? |
| 751 | |
| 752 | auto /*observable<PerfettoStateChange>*/ perfetto_states = |
| 753 | CreatePerfettoStateStream(trace_config, perfetto_consumer); |
| 754 | |
| 755 | using State = ::perfetto::consumer::State; |
| 756 | |
| 757 | auto/*coordinator*/ serialize_coordinator = rxcpp::observe_on_new_thread(); |
| 758 | // Rx note: |
| 759 | // The optimal thing to do would be to have a lock/unlock for an entire subset of a chain. |
| 760 | // This would avoid creating new threads, and could also be used to intentionally block |
| 761 | // the regular C-callback perfetto thread. |
| 762 | // |
| 763 | // It seems possible to create a coordinator to lock a single operator in a chain, but this |
| 764 | // appears to be unsound. In particular, it doesn't even make life any simpler below because |
| 765 | // it would only apply the synchronization to 'zip' but not 'flat_map' which is unsound. |
| 766 | // |
| 767 | // There is also the built-in 'serialize_new_thread' which seems to create a new thread but |
| 768 | // then never actually uses it, that seems unfortunate and wasteful. |
| 769 | // |
| 770 | // Instead, do the simple thing which is create a new thread and always queue on there. |
| 771 | // Execution an action on that worker is itself unsynchronized, but this doesn't matter since |
| 772 | // the worker is only backed by 1 thread (no 2 schedulables can be executed concurrently |
| 773 | // on the 'observe_new_thread' worker). |
| 774 | return input |
| 775 | .tap([](PerfettoStreamCommand command) { |
| 776 | LOG(VERBOSE) << "CreatePerfettoStreamCommand#tap(command=" << command << ")"; |
| 777 | }) |
| 778 | // Input A, thread tA. Input B, thread tB. Continue execution with (A,B) on thread tC. |
| 779 | .zip(serialize_coordinator, // rest of chain is also executed on the same thread. |
| 780 | perfetto_states) |
| 781 | // Note: zip terminates when either of the streams complete. |
| 782 | .flat_map( |
| 783 | [](std::tuple<PerfettoStreamCommand, PerfettoStateChange> p) { |
| 784 | auto& [command, state_change] = p; |
| 785 | LOG(VERBOSE) << "CreatePerfettoStream#combine(" |
| 786 | << command << "," << state_change << ")"; |
| 787 | if (command == PerfettoStreamCommand::kShutdown) { |
| 788 | // Perfetto: Always safe to call ::perfetto::consumer::Destroy |
| 789 | // at any time. |
| 790 | // |
| 791 | // XX: How do we clean up the StateChangedSubject without racing |
| 792 | // against the callback? It strikes me that we may need a 'kDestroyed' |
| 793 | // state that perfetto can transition to from kConfigured. |
| 794 | LOG(VERBOSE) << "Call Perfetto_Consumer->Destroy"; |
| 795 | state_change.GetConsumer()->Destroy(state_change.GetHandle()); |
| 796 | |
| 797 | // XX: Do we even have any guarantees about not getting more callbacks? |
| 798 | // We could just say 'there can still be spurious output after Shutdown' |
| 799 | // and just ignore it (e.g. Shutdown and immediately unsubscribe). |
| 800 | } else if (command == PerfettoStreamCommand::kStartTracing |
| 801 | && state_change.state == State::kConfigured) { |
| 802 | LOG(VERBOSE) << "Call Perfetto_Consumer->StartTracing"; |
| 803 | state_change.GetConsumer()->StartTracing(state_change.GetHandle()); |
| 804 | } else if (command == PerfettoStreamCommand::kStopTracing && |
| 805 | state_change.state == State::kTraceEnded) { |
| 806 | // TODO: if perfetto actually had a 'StopTracing' we could call that here. |
| 807 | // right now we just pretend it exists, but rely on the config timer instead. |
| 808 | ::perfetto::consumer::TraceBuffer trace_buffer = |
| 809 | state_change.GetConsumer()->ReadTrace(state_change.GetHandle()); |
| 810 | |
| 811 | LOG(VERBOSE) << "Perfetto Trace ended" |
| 812 | << ", addr=" << reinterpret_cast<void*>(trace_buffer.begin) |
| 813 | << ",size= " << trace_buffer.size; |
| 814 | |
| 815 | PerfettoTraceProto wire_proto{trace_buffer.begin, trace_buffer.size}; |
| 816 | return rxcpp::observable<>::just(std::move(wire_proto)).as_dynamic(); |
| 817 | } |
| 818 | return rxcpp::observable<>::empty<PerfettoTraceProto>().as_dynamic(); |
| 819 | } |
| 820 | ); |
| 821 | } |
| 822 | |
| 823 | std::ostream& operator<<(std::ostream& os, PerfettoStreamCommand c) { |
| 824 | switch (c) { |
| 825 | case PerfettoStreamCommand::kStartTracing: |
| 826 | os << "kStartTracing"; |
| 827 | break; |
| 828 | case PerfettoStreamCommand::kStopTracing: |
| 829 | os << "kStopTracing"; |
| 830 | break; |
| 831 | case PerfettoStreamCommand::kShutdown: |
| 832 | os << "kShutdown"; |
| 833 | break; |
| 834 | default: |
| 835 | os << "(unknown)"; |
| 836 | break; |
| 837 | } |
| 838 | return os; |
| 839 | } |
| 840 | |
| 841 | RxProducerFactory::RxProducerFactory(PerfettoDependencies::Injector& injector) |
| 842 | : injector_(injector) { |
| 843 | } |
| 844 | |
| 845 | // TODO: (fruit) maybe this could be streamlined further by avoiding this boilerplate? |
| 846 | rxcpp::observable<PerfettoTraceProto> RxProducerFactory::CreateTraceStream( |
| 847 | rxcpp::observable<PerfettoStreamCommand> commands) { |
| 848 | std::shared_ptr<PerfettoConsumer> perfetto_consumer = |
| 849 | injector_.get<std::shared_ptr<PerfettoConsumer>>(); |
| 850 | const ::perfetto::protos::TraceConfig& trace_config = |
| 851 | injector_.get<::perfetto::protos::TraceConfig>(); |
| 852 | |
| 853 | DCHECK(perfetto_consumer != nullptr); |
| 854 | DCHECK(reinterpret_cast<volatile const void*>(&trace_config) != nullptr); |
| 855 | |
| 856 | return CreatePerfettoStream(commands, |
| 857 | perfetto_consumer, |
| 858 | trace_config); |
| 859 | } |
| 860 | |
| 861 | // For testing/debugging only. |
| 862 | // |
| 863 | // Saves protobuf results in file name specified by 'arg_output_proto'. |
| 864 | void CollectPerfettoTraceBufferImmediately( |
| 865 | RxProducerFactory& producer_factory, |
| 866 | const std::string& arg_output_proto) { |
| 867 | LOG(VERBOSE) << "CollectPerfettoTraceBufferImmediately"; |
| 868 | |
| 869 | std::shared_ptr<PerfettoConsumer> perfetto_consumer = |
| 870 | producer_factory.injector_.get<std::shared_ptr<PerfettoConsumer>>(); |
| 871 | const ::perfetto::protos::TraceConfig& trace_config = |
| 872 | producer_factory.injector_.get<const ::perfetto::protos::TraceConfig&>(); |
| 873 | |
| 874 | auto /*observable<PerfettoStateChange>*/ perfetto_states = |
| 875 | CreatePerfettoStateStream(trace_config, perfetto_consumer); |
| 876 | |
| 877 | perfetto_states |
| 878 | .as_blocking() // Wait for observable to terminate with on_completed or on_error. |
| 879 | .subscribe(/*on_next*/[&](auto state_change) { |
| 880 | LOG(VERBOSE) << "Perfetto post-processed State change: " << state_change; |
| 881 | |
| 882 | using State = ::perfetto::consumer::State; |
| 883 | switch (state_change.state) { |
| 884 | case State::kConnecting: |
| 885 | LOG(VERBOSE) << "Perfetto Tracing is Connecting"; |
| 886 | // Transitional state. No-op. |
| 887 | break; |
| 888 | case State::kConfigured: |
| 889 | state_change.GetConsumer()->StartTracing(state_change.GetHandle()); |
| 890 | break; |
| 891 | case State::kTracing: |
| 892 | LOG(VERBOSE) << "Perfetto Tracing started"; |
| 893 | // Transitional state. No-op. |
| 894 | break; |
| 895 | case State::kTraceEnded: { |
| 896 | ::perfetto::consumer::TraceBuffer trace_buffer = |
| 897 | state_change.GetConsumer()->ReadTrace(state_change.GetHandle()); |
| 898 | |
| 899 | LOG(VERBOSE) << "Perfetto Trace ended" |
| 900 | << ", addr=" << reinterpret_cast<void*>(trace_buffer.begin) |
| 901 | << ",size= " << trace_buffer.size; |
| 902 | |
| 903 | if (!arg_output_proto.empty()) { |
| 904 | std::string trace_buffer_str; |
| 905 | trace_buffer_str.resize(trace_buffer.size); |
| 906 | std::copy(trace_buffer.begin, |
| 907 | trace_buffer.begin + trace_buffer.size, |
| 908 | trace_buffer_str.data()); |
| 909 | if (!android::base::WriteStringToFile(trace_buffer_str, arg_output_proto)) { |
| 910 | LOG(ERROR) << "Failed to save TraceBuffer to " << arg_output_proto; |
| 911 | } else { |
| 912 | LOG(INFO) << "TraceBuffer saved to file: " << arg_output_proto; |
| 913 | LOG(INFO); |
| 914 | LOG(INFO) << "To print this in a human readable form, execute these commands:"; |
| 915 | LOG(INFO) << "$> adb pull '" << arg_output_proto << "'"; |
| 916 | LOG(INFO) << "$> trace_to_text systrace <filename.pb>"; |
| 917 | } |
| 918 | } |
| 919 | |
| 920 | // TODO: something more useful with this TraceBuffer, such as saving it to a file |
| 921 | // and printing the output. |
| 922 | break; |
| 923 | } |
| 924 | default: |
| 925 | // No other states are possible, because they go to #on_error or cause a dcheck. |
| 926 | DCHECK(false) << "Invalid state: " << state_change; |
| 927 | } |
| 928 | |
| 929 | //INTENTIONAL_COMPILER_ERROR_HERE // lets make sure this code actually does a trace. |
| 930 | |
| 931 | }, /*on_error*/[](rxcpp::util::error_ptr err) { |
| 932 | LOG(ERROR) << "Perfetto post-processed state change failed: " << rxcpp::util::what(err); |
| 933 | }, /*on_completed*/[]() { |
| 934 | LOG(VERBOSE) << "Perfetto post-processed State #on_completed"; |
| 935 | }); |
| 936 | } |
| 937 | |
| 938 | |
| 939 | } // namespace iorap::perfetto |