src/trace_processor/slice_tracker.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2018 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 <limits>

 #include <stdint.h>

 #include "src/trace_processor/args_tracker.h"
 #include "src/trace_processor/process_tracker.h"
 #include "src/trace_processor/slice_tracker.h"
 #include "src/trace_processor/trace_processor_context.h"
 #include "src/trace_processor/trace_storage.h"

 namespace perfetto {
 namespace trace_processor {
 namespace {
 // Slices which have been opened but haven't been closed yet will be marked
 // with this duration placeholder.
 constexpr int64_t kPendingDuration = -1;
 }  // namespace

 SliceTracker::SliceTracker(TraceProcessorContext* context)
     : context_(context) {}

 SliceTracker::~SliceTracker() = default;

 base::Optional<uint32_t> SliceTracker::BeginAndroid(int64_t timestamp,
                                                     uint32_t ftrace_tid,
                                                     uint32_t atrace_tgid,
                                                     StringId category,
                                                     StringId name) {
   UniqueTid utid =
       context_->process_tracker->UpdateThread(ftrace_tid, atrace_tgid);
   ftrace_to_atrace_tgid_[ftrace_tid] = atrace_tgid;
   return Begin(timestamp, utid, RefType::kRefUtid, category, name);
 }

 base::Optional<uint32_t> SliceTracker::Begin(int64_t timestamp,
                                              int64_t ref,
                                              RefType ref_type,
                                              StringId category,
                                              StringId name,
                                              SetArgsCallback args_callback) {
   // At this stage all events should be globally timestamp ordered.
   if (timestamp < prev_timestamp_) {
     context_->storage->IncrementStats(stats::slice_out_of_order);
     return base::nullopt;
   }
   prev_timestamp_ = timestamp;

   MaybeCloseStack(timestamp, &stacks_[{ref, ref_type}]);
   return StartSlice(timestamp, kPendingDuration, ref, ref_type, category, name,
                     args_callback);
 }

 base::Optional<uint32_t> SliceTracker::Scoped(int64_t timestamp,
                                               int64_t ref,
                                               RefType ref_type,
                                               StringId category,
                                               StringId name,
                                               int64_t duration,
                                               SetArgsCallback args_callback) {
   // At this stage all events should be globally timestamp ordered.
   if (timestamp < prev_timestamp_) {
     context_->storage->IncrementStats(stats::slice_out_of_order);
     return base::nullopt;
   }
   prev_timestamp_ = timestamp;

   PERFETTO_DCHECK(duration >= 0);
   MaybeCloseStack(timestamp, &stacks_[{ref, ref_type}]);
   return StartSlice(timestamp, duration, ref, ref_type, category, name,
                     args_callback);
 }

 base::Optional<uint32_t> SliceTracker::StartSlice(
     int64_t timestamp,
     int64_t duration,
     int64_t ref,
     RefType ref_type,
     StringId category,
     StringId name,
     SetArgsCallback args_callback) {
   auto* stack = &stacks_[{ref, ref_type}];
   auto* slices = context_->storage->mutable_nestable_slices();

   const uint8_t depth = static_cast<uint8_t>(stack->size());
   if (depth >= std::numeric_limits<uint8_t>::max()) {
     PERFETTO_DFATAL("Slices with too large depth found.");
     return base::nullopt;
   }
   int64_t parent_stack_id =
       depth == 0 ? 0 : slices->stack_ids()[stack->back().first];
   uint32_t slice_idx =
       slices->AddSlice(timestamp, duration, ref, ref_type, category, name,
                        depth, 0, parent_stack_id);
   stack->emplace_back(std::make_pair(slice_idx, ArgsTracker(context_)));

   if (args_callback) {
     args_callback(
         &stack->back().second,
         TraceStorage::CreateRowId(TableId::kNestableSlices, slice_idx));
   }
   slices->set_stack_id(slice_idx, GetStackHash(*stack));
   return slice_idx;
 }

 base::Optional<uint32_t> SliceTracker::EndAndroid(int64_t timestamp,
                                                   uint32_t ftrace_tid,
                                                   uint32_t atrace_tgid) {
   auto actual_tgid_it = ftrace_to_atrace_tgid_.find(ftrace_tid);
   if (actual_tgid_it == ftrace_to_atrace_tgid_.end()) {
     // This is possible if we start tracing after a begin slice.
     PERFETTO_DLOG("Unknown tgid for ftrace tid %u", ftrace_tid);
     return base::nullopt;
   }
   uint32_t actual_tgid = actual_tgid_it->second;
   // atrace_tgid can be 0 in older android versions where the end event would
   // not contain the value.
   if (atrace_tgid != 0 && atrace_tgid != actual_tgid) {
     PERFETTO_DLOG("Mismatched atrace pid %u and looked up pid %u", atrace_tgid,
                   actual_tgid);
     context_->storage->IncrementStats(stats::atrace_tgid_mismatch);
   }
   UniqueTid utid =
       context_->process_tracker->UpdateThread(ftrace_tid, actual_tgid);
   return End(timestamp, utid, RefType::kRefUtid);
 }

 base::Optional<uint32_t> SliceTracker::End(int64_t timestamp,
                                            int64_t ref,
                                            RefType ref_type,
                                            StringId category,
                                            StringId name,
                                            SetArgsCallback args_callback) {
   // At this stage all events should be globally timestamp ordered.
   if (timestamp < prev_timestamp_) {
     context_->storage->IncrementStats(stats::slice_out_of_order);
     return base::nullopt;
   }
   prev_timestamp_ = timestamp;

   StackMapKey stack_key = {ref, ref_type};
   MaybeCloseStack(timestamp, &stacks_[stack_key]);

   auto& stack = stacks_[stack_key];
   if (stack.empty())
     return base::nullopt;

   auto* slices = context_->storage->mutable_nestable_slices();
   uint32_t slice_idx = stack.back().first;

   // If we are trying to close mismatching slices (e.g., slices that began
   // before tracing started), bail out.
   if (!category.is_null() && slices->categories()[slice_idx] != category)
     return base::nullopt;
   if (!name.is_null() && slices->names()[slice_idx] != name)
     return base::nullopt;

   PERFETTO_DCHECK(slices->durations()[slice_idx] == kPendingDuration);
   slices->set_duration(slice_idx, timestamp - slices->start_ns()[slice_idx]);

   if (args_callback) {
     args_callback(
         &stack.back().second,
         TraceStorage::CreateRowId(TableId::kNestableSlices, slice_idx));
   }

   return CompleteSlice(stack_key);
   // TODO(primiano): auto-close B slices left open at the end.
 }

 void SliceTracker::FlushPendingSlices() {
   // Clear the remaining stack entries. This ensures that any pending args are
   // written to the storage. We don't close any slices with kPendingDuration so
   // that the UI can still distinguish such "incomplete" slices.
   //
   // TODO(eseckler): Reconsider whether we want to close pending slices by
   // setting their duration to |trace_end - event_start|. Might still want some
   // additional way of flagging these events as "incomplete" to the UI.
   stacks_.clear();
 }

 base::Optional<uint32_t> SliceTracker::CompleteSlice(StackMapKey stack_key) {
   auto& stack = stacks_[stack_key];
   uint32_t slice_idx = stack.back().first;
   stack.pop_back();
   return slice_idx;
 }

 void SliceTracker::MaybeCloseStack(int64_t ts, SlicesStack* stack) {
   const auto& slices = context_->storage->nestable_slices();
   bool pending_dur_descendent = false;
   for (int i = static_cast<int>(stack->size()) - 1; i >= 0; i--) {
     uint32_t slice_idx = (*stack)[static_cast<size_t>(i)].first;

     int64_t start_ts = slices.start_ns()[slice_idx];
     int64_t dur = slices.durations()[slice_idx];
     int64_t end_ts = start_ts + dur;
     if (dur == kPendingDuration) {
       pending_dur_descendent = true;
     }

     if (pending_dur_descendent) {
       PERFETTO_DCHECK(ts >= start_ts);
       // Some trace producers emit END events in the wrong order (even after
       // sorting by timestamp), e.g. BEGIN A, BEGIN B, END A, END B. We discard
       // the mismatching END A in End(). Because of this, we can end up in a
       // situation where we attempt to close the stack on top of A at a
       // timestamp beyond A's parent. To avoid crashing in such a case, we just
       // emit a warning instead.
       if (dur != kPendingDuration && ts > end_ts) {
         PERFETTO_DLOG(
             "Incorrect ordering of begin/end slice events around timestamp "
             "%" PRId64,
             ts);
       }
       continue;
     }

     if (end_ts <= ts) {
       stack->pop_back();
     }
   }
 }

 int64_t SliceTracker::GetStackHash(const SlicesStack& stack) {
   PERFETTO_DCHECK(!stack.empty());

   const auto& slices = context_->storage->nestable_slices();

   std::string s;
   s.reserve(stack.size() * sizeof(uint64_t) * 2);
   for (size_t i = 0; i < stack.size(); i++) {
     uint32_t slice_idx = stack[i].first;
     s.append(reinterpret_cast<const char*>(&slices.categories()[slice_idx]),
              sizeof(slices.categories()[slice_idx]));
     s.append(reinterpret_cast<const char*>(&slices.names()[slice_idx]),
              sizeof(slices.names()[slice_idx]));
   }
   constexpr uint64_t kMask = uint64_t(-1) >> 1;
   return static_cast<int64_t>((std::hash<std::string>{}(s)) & kMask);
 }

 }  // namespace trace_processor
 }  // namespace perfetto
	/*
	* Copyright (C) 2018 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 <limits>

	#include <stdint.h>

	#include "src/trace_processor/args_tracker.h"
	#include "src/trace_processor/process_tracker.h"
	#include "src/trace_processor/slice_tracker.h"
	#include "src/trace_processor/trace_processor_context.h"
	#include "src/trace_processor/trace_storage.h"

	namespace perfetto {
	namespace trace_processor {
	namespace {
	// Slices which have been opened but haven't been closed yet will be marked
	// with this duration placeholder.
	constexpr int64_t kPendingDuration = -1;
	} // namespace

	SliceTracker::SliceTracker(TraceProcessorContext* context)
	: context_(context) {}

	SliceTracker::~SliceTracker() = default;

	base::Optional<uint32_t> SliceTracker::BeginAndroid(int64_t timestamp,
	uint32_t ftrace_tid,
	uint32_t atrace_tgid,
	StringId category,
	StringId name) {
	UniqueTid utid =
	context_->process_tracker->UpdateThread(ftrace_tid, atrace_tgid);
	ftrace_to_atrace_tgid_[ftrace_tid] = atrace_tgid;
	return Begin(timestamp, utid, RefType::kRefUtid, category, name);
	}

	base::Optional<uint32_t> SliceTracker::Begin(int64_t timestamp,
	int64_t ref,
	RefType ref_type,
	StringId category,
	StringId name,
	SetArgsCallback args_callback) {
	// At this stage all events should be globally timestamp ordered.
	if (timestamp < prev_timestamp_) {
	context_->storage->IncrementStats(stats::slice_out_of_order);
	return base::nullopt;
	}
	prev_timestamp_ = timestamp;

	MaybeCloseStack(timestamp, &stacks_[{ref, ref_type}]);
	return StartSlice(timestamp, kPendingDuration, ref, ref_type, category, name,
	args_callback);
	}

	base::Optional<uint32_t> SliceTracker::Scoped(int64_t timestamp,
	int64_t ref,
	RefType ref_type,
	StringId category,
	StringId name,
	int64_t duration,
	SetArgsCallback args_callback) {
	// At this stage all events should be globally timestamp ordered.
	if (timestamp < prev_timestamp_) {
	context_->storage->IncrementStats(stats::slice_out_of_order);
	return base::nullopt;
	}
	prev_timestamp_ = timestamp;

	PERFETTO_DCHECK(duration >= 0);
	MaybeCloseStack(timestamp, &stacks_[{ref, ref_type}]);
	return StartSlice(timestamp, duration, ref, ref_type, category, name,
	args_callback);
	}

	base::Optional<uint32_t> SliceTracker::StartSlice(
	int64_t timestamp,
	int64_t duration,
	int64_t ref,
	RefType ref_type,
	StringId category,
	StringId name,
	SetArgsCallback args_callback) {
	auto* stack = &stacks_[{ref, ref_type}];
	auto* slices = context_->storage->mutable_nestable_slices();

	const uint8_t depth = static_cast<uint8_t>(stack->size());
	if (depth >= std::numeric_limits<uint8_t>::max()) {
	PERFETTO_DFATAL("Slices with too large depth found.");
	return base::nullopt;
	}
	int64_t parent_stack_id =
	depth == 0 ? 0 : slices->stack_ids()[stack->back().first];
	uint32_t slice_idx =
	slices->AddSlice(timestamp, duration, ref, ref_type, category, name,
	depth, 0, parent_stack_id);
	stack->emplace_back(std::make_pair(slice_idx, ArgsTracker(context_)));

	if (args_callback) {
	args_callback(
	&stack->back().second,
	TraceStorage::CreateRowId(TableId::kNestableSlices, slice_idx));
	}
	slices->set_stack_id(slice_idx, GetStackHash(*stack));
	return slice_idx;
	}

	base::Optional<uint32_t> SliceTracker::EndAndroid(int64_t timestamp,
	uint32_t ftrace_tid,
	uint32_t atrace_tgid) {
	auto actual_tgid_it = ftrace_to_atrace_tgid_.find(ftrace_tid);
	if (actual_tgid_it == ftrace_to_atrace_tgid_.end()) {
	// This is possible if we start tracing after a begin slice.
	PERFETTO_DLOG("Unknown tgid for ftrace tid %u", ftrace_tid);
	return base::nullopt;
	}
	uint32_t actual_tgid = actual_tgid_it->second;
	// atrace_tgid can be 0 in older android versions where the end event would
	// not contain the value.
	if (atrace_tgid != 0 && atrace_tgid != actual_tgid) {
	PERFETTO_DLOG("Mismatched atrace pid %u and looked up pid %u", atrace_tgid,
	actual_tgid);
	context_->storage->IncrementStats(stats::atrace_tgid_mismatch);
	}
	UniqueTid utid =
	context_->process_tracker->UpdateThread(ftrace_tid, actual_tgid);
	return End(timestamp, utid, RefType::kRefUtid);
	}

	base::Optional<uint32_t> SliceTracker::End(int64_t timestamp,
	int64_t ref,
	RefType ref_type,
	StringId category,
	StringId name,
	SetArgsCallback args_callback) {
	// At this stage all events should be globally timestamp ordered.
	if (timestamp < prev_timestamp_) {
	context_->storage->IncrementStats(stats::slice_out_of_order);
	return base::nullopt;
	}
	prev_timestamp_ = timestamp;

	StackMapKey stack_key = {ref, ref_type};
	MaybeCloseStack(timestamp, &stacks_[stack_key]);

	auto& stack = stacks_[stack_key];
	if (stack.empty())
	return base::nullopt;

	auto* slices = context_->storage->mutable_nestable_slices();
	uint32_t slice_idx = stack.back().first;

	// If we are trying to close mismatching slices (e.g., slices that began
	// before tracing started), bail out.
	if (!category.is_null() && slices->categories()[slice_idx] != category)
	return base::nullopt;
	if (!name.is_null() && slices->names()[slice_idx] != name)
	return base::nullopt;

	PERFETTO_DCHECK(slices->durations()[slice_idx] == kPendingDuration);
	slices->set_duration(slice_idx, timestamp - slices->start_ns()[slice_idx]);

	if (args_callback) {
	args_callback(
	&stack.back().second,
	TraceStorage::CreateRowId(TableId::kNestableSlices, slice_idx));
	}

	return CompleteSlice(stack_key);
	// TODO(primiano): auto-close B slices left open at the end.
	}

	void SliceTracker::FlushPendingSlices() {
	// Clear the remaining stack entries. This ensures that any pending args are
	// written to the storage. We don't close any slices with kPendingDuration so
	// that the UI can still distinguish such "incomplete" slices.
	//
	// TODO(eseckler): Reconsider whether we want to close pending slices by
	// setting their duration to \|trace_end - event_start\|. Might still want some
	// additional way of flagging these events as "incomplete" to the UI.
	stacks_.clear();
	}

	base::Optional<uint32_t> SliceTracker::CompleteSlice(StackMapKey stack_key) {
	auto& stack = stacks_[stack_key];
	uint32_t slice_idx = stack.back().first;
	stack.pop_back();
	return slice_idx;
	}

	void SliceTracker::MaybeCloseStack(int64_t ts, SlicesStack* stack) {
	const auto& slices = context_->storage->nestable_slices();
	bool pending_dur_descendent = false;
	for (int i = static_cast<int>(stack->size()) - 1; i >= 0; i--) {
	uint32_t slice_idx = (*stack)[static_cast<size_t>(i)].first;

	int64_t start_ts = slices.start_ns()[slice_idx];
	int64_t dur = slices.durations()[slice_idx];
	int64_t end_ts = start_ts + dur;
	if (dur == kPendingDuration) {
	pending_dur_descendent = true;
	}

	if (pending_dur_descendent) {
	PERFETTO_DCHECK(ts >= start_ts);
	// Some trace producers emit END events in the wrong order (even after
	// sorting by timestamp), e.g. BEGIN A, BEGIN B, END A, END B. We discard
	// the mismatching END A in End(). Because of this, we can end up in a
	// situation where we attempt to close the stack on top of A at a
	// timestamp beyond A's parent. To avoid crashing in such a case, we just
	// emit a warning instead.
	if (dur != kPendingDuration && ts > end_ts) {
	PERFETTO_DLOG(
	"Incorrect ordering of begin/end slice events around timestamp "
	"%" PRId64,
	ts);
	}
	continue;
	}

	if (end_ts <= ts) {
	stack->pop_back();
	}
	}
	}

	int64_t SliceTracker::GetStackHash(const SlicesStack& stack) {
	PERFETTO_DCHECK(!stack.empty());

	const auto& slices = context_->storage->nestable_slices();

	std::string s;
	s.reserve(stack.size() * sizeof(uint64_t) * 2);
	for (size_t i = 0; i < stack.size(); i++) {
	uint32_t slice_idx = stack[i].first;
	s.append(reinterpret_cast<const char*>(&slices.categories()[slice_idx]),
	sizeof(slices.categories()[slice_idx]));
	s.append(reinterpret_cast<const char*>(&slices.names()[slice_idx]),
	sizeof(slices.names()[slice_idx]));
	}
	constexpr uint64_t kMask = uint64_t(-1) >> 1;
	return static_cast<int64_t>((std::hash<std::string>{}(s)) & kMask);
	}

	} // namespace trace_processor
	} // namespace perfetto