src/trace_processor/process_tracker.cc - platform/external/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 "src/trace_processor/process_tracker.h"
 #include "src/trace_processor/stats.h"

 #include <utility>

 #include <inttypes.h>

 namespace perfetto {
 namespace trace_processor {

 ProcessTracker::ProcessTracker(TraceProcessorContext* context)
     : context_(context) {
   // Create a mapping from (t|p)id 0 -> u(t|p)id 0 for the idle process.
   tids_.emplace(0, 0);
   pids_.emplace(0, 0);
 }

 ProcessTracker::~ProcessTracker() = default;

 UniqueTid ProcessTracker::StartNewThread(int64_t timestamp,
                                          uint32_t tid,
                                          StringId thread_name_id) {
   UniqueTid new_utid = context_->storage->AddEmptyThread(tid);
   TraceStorage::Thread* thread = context_->storage->GetMutableThread(new_utid);
   thread->name_id = thread_name_id;
   thread->start_ns = timestamp;
   tids_.emplace(tid, new_utid);
   return new_utid;
 }

 UniqueTid ProcessTracker::UpdateThread(int64_t timestamp,
                                        uint32_t tid,
                                        StringId thread_name_id) {
   auto pair_it = tids_.equal_range(tid);

   // If a utid exists for the tid, find it and update the name.
   if (pair_it.first != pair_it.second) {
     auto prev_utid = std::prev(pair_it.second)->second;
     TraceStorage::Thread* thread =
         context_->storage->GetMutableThread(prev_utid);
     if (thread_name_id)
       thread->name_id = thread_name_id;
     return prev_utid;
   }

   // If none exist, assign a new utid and store it.
   return StartNewThread(timestamp, tid, thread_name_id);
 }

 UniqueTid ProcessTracker::UpdateThread(uint32_t tid, uint32_t pid) {
   auto tids_pair = tids_.equal_range(tid);

   // Try looking for a thread that matches both tid and thread group id (pid).
   TraceStorage::Thread* thread = nullptr;
   UniqueTid utid = 0;
   for (auto it = tids_pair.first; it != tids_pair.second; it++) {
     UniqueTid iter_utid = it->second;
     auto* iter_thread = context_->storage->GetMutableThread(iter_utid);
     if (!iter_thread->upid.has_value()) {
       // We haven't discovered the parent process for the thread. Assign it
       // now and use this thread.
       thread = iter_thread;
       utid = iter_utid;
       break;
     }
     const auto& iter_process =
         context_->storage->GetProcess(iter_thread->upid.value());
     if (iter_process.pid == pid) {
       // We found a thread that matches both the tid and its parent pid.
       thread = iter_thread;
       utid = iter_utid;
       break;
     }
   }  // for(tids).

   // If no matching thread was found, create a new one.
   if (thread == nullptr) {
     utid = context_->storage->AddEmptyThread(tid);
     tids_.emplace(tid, utid);
     thread = context_->storage->GetMutableThread(utid);
   }

   // Find matching process or create new one.
   if (!thread->upid.has_value()) {
     std::tie(thread->upid, std::ignore) =
         GetOrCreateProcess(pid, thread->start_ns);
   }

   ResolvePendingAssociations(utid, *thread->upid);

   return utid;
 }

 UniquePid ProcessTracker::StartNewProcess(int64_t timestamp, uint32_t pid) {
   pids_.erase(pid);

   // Create a new UTID for the main thread, so we don't end up reusing an old
   // entry in case of TID recycling.
   StartNewThread(timestamp, /*tid=*/pid, 0);

   UniquePid upid = UpdateProcess(pid, timestamp);
   return upid;
 }

 UniquePid ProcessTracker::UpdateProcess(uint32_t pid,
                                         base::Optional<uint32_t> ppid,
                                         base::StringView name) {
   auto proc_name_id = context_->storage->InternString(name);

   UniquePid upid;
   TraceStorage::Process* process;
   std::tie(upid, process) = GetOrCreateProcess(pid, 0 /* start_ns */);
   process->name_id = proc_name_id;
   if (ppid.has_value()) {
     process->pupid = GetOrCreateProcess(ppid.value(), 0 /* start_ns */).first;
   }
   return upid;
 }

 UniquePid ProcessTracker::UpdateProcess(uint32_t pid, int64_t start_ns) {
   UniquePid upid;
   std::tie(upid, std::ignore) = GetOrCreateProcess(pid, start_ns);
   return upid;
 }

 std::pair<UniquePid, TraceStorage::Process*> ProcessTracker::GetOrCreateProcess(
     uint32_t pid,
     int64_t start_ns) {
   UniquePid upid;
   auto it = pids_.find(pid);
   if (it != pids_.end()) {
     upid = it->second;
   } else {
     upid = context_->storage->AddEmptyProcess(pid);
     pids_.emplace(pid, upid);

     // Create an entry for the main thread.
     // We cannot call StartNewThread() here, because threads for this process
     // (including the main thread) might have been seen already prior to this
     // call. This call usually comes from the ProcessTree dump which is delayed.
     UpdateThread(/*tid=*/pid, pid);
   }

   auto* process = context_->storage->GetMutableProcess(upid);
   if (process->start_ns == 0)
     process->start_ns = start_ns;

   return std::make_pair(upid, process);
 }

 void ProcessTracker::AssociateThreads(UniqueTid utid1, UniqueTid utid2) {
   TraceStorage::Thread* thd1 = context_->storage->GetMutableThread(utid1);
   TraceStorage::Thread* thd2 = context_->storage->GetMutableThread(utid2);

   // First of all check if one of the two threads is already bound to a process.
   // If that is the case, map the other thread to the same process and resolve
   // recursively any associations pending on the other thread.

   if (thd1->upid.has_value() && !thd2->upid.has_value()) {
     thd2->upid = *thd1->upid;
     ResolvePendingAssociations(utid2, *thd1->upid);
     return;
   }

   if (thd2->upid.has_value() && !thd1->upid.has_value()) {
     thd1->upid = *thd2->upid;
     ResolvePendingAssociations(utid1, *thd2->upid);
     return;
   }

   if (thd1->upid.has_value() && thd1->upid != thd2->upid) {
     // Cannot associate two threads that belong to two different processes.
     PERFETTO_ELOG("Process tracker failure. Cannot associate threads %u, %u",
                   thd1->tid, thd2->tid);
     context_->storage->IncrementStats(stats::process_tracker_errors);
     return;
   }

   pending_assocs_.emplace_back(utid1, utid2);
 }

 void ProcessTracker::ResolvePendingAssociations(UniqueTid utid_arg,
                                                 UniquePid upid) {
   PERFETTO_DCHECK(context_->storage->GetMutableThread(utid_arg)->upid == upid);
   std::vector<UniqueTid> resolved_utids;
   resolved_utids.emplace_back(utid_arg);

   while (!resolved_utids.empty()) {
     UniqueTid utid = resolved_utids.back();
     resolved_utids.pop_back();
     for (auto it = pending_assocs_.begin(); it != pending_assocs_.end();) {
       UniqueTid other_utid;
       if (it->first == utid) {
         other_utid = it->second;
       } else if (it->second == utid) {
         other_utid = it->first;
       } else {
         ++it;
         continue;
       }

       PERFETTO_DCHECK(other_utid != utid);

       // Update the other thread and associated it to the same process.
       auto* other_thd = context_->storage->GetMutableThread(other_utid);
       PERFETTO_DCHECK(!other_thd->upid || other_thd->upid == upid);
       other_thd->upid = upid;

       // Erase the pair. The |pending_assocs_| vector is not sorted and swapping
       // a std::pair<uint32_t, uint32_t> is cheap.
       std::swap(*it, pending_assocs_.back());
       pending_assocs_.pop_back();

       // Recurse into the newly resolved thread. Some other threads might have
       // been bound to that.
       resolved_utids.emplace_back(other_utid);
     }
   }  // while (!resolved_utids.empty())
 }

 }  // 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 "src/trace_processor/process_tracker.h"
	#include "src/trace_processor/stats.h"

	#include <utility>

	#include <inttypes.h>

	namespace perfetto {
	namespace trace_processor {

	ProcessTracker::ProcessTracker(TraceProcessorContext* context)
	: context_(context) {
	// Create a mapping from (t\|p)id 0 -> u(t\|p)id 0 for the idle process.
	tids_.emplace(0, 0);
	pids_.emplace(0, 0);
	}

	ProcessTracker::~ProcessTracker() = default;

	UniqueTid ProcessTracker::StartNewThread(int64_t timestamp,
	uint32_t tid,
	StringId thread_name_id) {
	UniqueTid new_utid = context_->storage->AddEmptyThread(tid);
	TraceStorage::Thread* thread = context_->storage->GetMutableThread(new_utid);
	thread->name_id = thread_name_id;
	thread->start_ns = timestamp;
	tids_.emplace(tid, new_utid);
	return new_utid;
	}

	UniqueTid ProcessTracker::UpdateThread(int64_t timestamp,
	uint32_t tid,
	StringId thread_name_id) {
	auto pair_it = tids_.equal_range(tid);

	// If a utid exists for the tid, find it and update the name.
	if (pair_it.first != pair_it.second) {
	auto prev_utid = std::prev(pair_it.second)->second;
	TraceStorage::Thread* thread =
	context_->storage->GetMutableThread(prev_utid);
	if (thread_name_id)
	thread->name_id = thread_name_id;
	return prev_utid;
	}

	// If none exist, assign a new utid and store it.
	return StartNewThread(timestamp, tid, thread_name_id);
	}

	UniqueTid ProcessTracker::UpdateThread(uint32_t tid, uint32_t pid) {
	auto tids_pair = tids_.equal_range(tid);

	// Try looking for a thread that matches both tid and thread group id (pid).
	TraceStorage::Thread* thread = nullptr;
	UniqueTid utid = 0;
	for (auto it = tids_pair.first; it != tids_pair.second; it++) {
	UniqueTid iter_utid = it->second;
	auto* iter_thread = context_->storage->GetMutableThread(iter_utid);
	if (!iter_thread->upid.has_value()) {
	// We haven't discovered the parent process for the thread. Assign it
	// now and use this thread.
	thread = iter_thread;
	utid = iter_utid;
	break;
	}
	const auto& iter_process =
	context_->storage->GetProcess(iter_thread->upid.value());
	if (iter_process.pid == pid) {
	// We found a thread that matches both the tid and its parent pid.
	thread = iter_thread;
	utid = iter_utid;
	break;
	}
	} // for(tids).

	// If no matching thread was found, create a new one.
	if (thread == nullptr) {
	utid = context_->storage->AddEmptyThread(tid);
	tids_.emplace(tid, utid);
	thread = context_->storage->GetMutableThread(utid);
	}

	// Find matching process or create new one.
	if (!thread->upid.has_value()) {
	std::tie(thread->upid, std::ignore) =
	GetOrCreateProcess(pid, thread->start_ns);
	}

	ResolvePendingAssociations(utid, *thread->upid);

	return utid;
	}

	UniquePid ProcessTracker::StartNewProcess(int64_t timestamp, uint32_t pid) {
	pids_.erase(pid);

	// Create a new UTID for the main thread, so we don't end up reusing an old
	// entry in case of TID recycling.
	StartNewThread(timestamp, /tid=/pid, 0);

	UniquePid upid = UpdateProcess(pid, timestamp);
	return upid;
	}

	UniquePid ProcessTracker::UpdateProcess(uint32_t pid,
	base::Optional<uint32_t> ppid,
	base::StringView name) {
	auto proc_name_id = context_->storage->InternString(name);

	UniquePid upid;
	TraceStorage::Process* process;
	std::tie(upid, process) = GetOrCreateProcess(pid, 0 /* start_ns */);
	process->name_id = proc_name_id;
	if (ppid.has_value()) {
	process->pupid = GetOrCreateProcess(ppid.value(), 0 /* start_ns */).first;
	}
	return upid;
	}

	UniquePid ProcessTracker::UpdateProcess(uint32_t pid, int64_t start_ns) {
	UniquePid upid;
	std::tie(upid, std::ignore) = GetOrCreateProcess(pid, start_ns);
	return upid;
	}

	std::pair<UniquePid, TraceStorage::Process*> ProcessTracker::GetOrCreateProcess(
	uint32_t pid,
	int64_t start_ns) {
	UniquePid upid;
	auto it = pids_.find(pid);
	if (it != pids_.end()) {
	upid = it->second;
	} else {
	upid = context_->storage->AddEmptyProcess(pid);
	pids_.emplace(pid, upid);

	// Create an entry for the main thread.
	// We cannot call StartNewThread() here, because threads for this process
	// (including the main thread) might have been seen already prior to this
	// call. This call usually comes from the ProcessTree dump which is delayed.
	UpdateThread(/tid=/pid, pid);
	}

	auto* process = context_->storage->GetMutableProcess(upid);
	if (process->start_ns == 0)
	process->start_ns = start_ns;

	return std::make_pair(upid, process);
	}

	void ProcessTracker::AssociateThreads(UniqueTid utid1, UniqueTid utid2) {
	TraceStorage::Thread* thd1 = context_->storage->GetMutableThread(utid1);
	TraceStorage::Thread* thd2 = context_->storage->GetMutableThread(utid2);

	// First of all check if one of the two threads is already bound to a process.
	// If that is the case, map the other thread to the same process and resolve
	// recursively any associations pending on the other thread.

	if (thd1->upid.has_value() && !thd2->upid.has_value()) {
	thd2->upid = *thd1->upid;
	ResolvePendingAssociations(utid2, *thd1->upid);
	return;
	}

	if (thd2->upid.has_value() && !thd1->upid.has_value()) {
	thd1->upid = *thd2->upid;
	ResolvePendingAssociations(utid1, *thd2->upid);
	return;
	}

	if (thd1->upid.has_value() && thd1->upid != thd2->upid) {
	// Cannot associate two threads that belong to two different processes.
	PERFETTO_ELOG("Process tracker failure. Cannot associate threads %u, %u",
	thd1->tid, thd2->tid);
	context_->storage->IncrementStats(stats::process_tracker_errors);
	return;
	}

	pending_assocs_.emplace_back(utid1, utid2);
	}

	void ProcessTracker::ResolvePendingAssociations(UniqueTid utid_arg,
	UniquePid upid) {
	PERFETTO_DCHECK(context_->storage->GetMutableThread(utid_arg)->upid == upid);
	std::vector<UniqueTid> resolved_utids;
	resolved_utids.emplace_back(utid_arg);

	while (!resolved_utids.empty()) {
	UniqueTid utid = resolved_utids.back();
	resolved_utids.pop_back();
	for (auto it = pending_assocs_.begin(); it != pending_assocs_.end();) {
	UniqueTid other_utid;
	if (it->first == utid) {
	other_utid = it->second;
	} else if (it->second == utid) {
	other_utid = it->first;
	} else {
	++it;
	continue;
	}

	PERFETTO_DCHECK(other_utid != utid);

	// Update the other thread and associated it to the same process.
	auto* other_thd = context_->storage->GetMutableThread(other_utid);
	PERFETTO_DCHECK(!other_thd->upid \|\| other_thd->upid == upid);
	other_thd->upid = upid;

	// Erase the pair. The \|pending_assocs_\| vector is not sorted and swapping
	// a std::pair<uint32_t, uint32_t> is cheap.
	std::swap(*it, pending_assocs_.back());
	pending_assocs_.pop_back();

	// Recurse into the newly resolved thread. Some other threads might have
	// been bound to that.
	resolved_utids.emplace_back(other_utid);
	}
	} // while (!resolved_utids.empty())
	}

	} // namespace trace_processor
	} // namespace perfetto