1 //==-- llvm/Support/ThreadPool.cpp - A ThreadPool implementation -*- C++ -*-==//
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
11 //===----------------------------------------------------------------------===//
15 #include "llvm/Config/llvm-config.h"
25 // A note on thread groups: Tasks are by default in no group (represented
26 // by nullptr ThreadPoolTaskGroup pointer in the Tasks queue) and functionality
27 // here normally works on all tasks regardless of their group (functions
29 // A task in a group has a pointer to that ThreadPoolTaskGroup in the Tasks
30 // queue, and functions called to work only on tasks from one group take that
46       set_thread_name(formatv("llvm-worker-{0}", ThreadID));  in grow()
54 // The group of the tasks run by the current thread.
59 // WaitingForGroup == nullptr means all tasks regardless of their group.
67       // Wait for tasks to be pushed in the queue  in processTasks()
79       // Yeah, we have a task, grab it and release the lock on the queue  in processTasks()
81       // We first need to signal that we are active before popping the queue  in processTasks()
82       // in order for wait() to properly detect that even if the queue is  in processTasks()
87       // Need to count active threads in each group separately, ActiveThreads  in processTasks()
88       // would never be 0 if waiting for another group inside a wait.  in processTasks()
96     CurrentThreadTaskGroups->push_back(GroupOfTask);  in processTasks()
103     CurrentThreadTaskGroups->pop_back();  in processTasks()
104     if (CurrentThreadTaskGroups->empty()) {  in processTasks()
115       --ActiveThreads;  in processTasks()
118         if (--(A->second) == 0)  in processTasks()
128     // If this was a task in a group, notify also threads waiting for tasks  in processTasks()
130     // after the group it's been waiting for has finished.  in processTasks()
136 bool StdThreadPool::workCompletedUnlocked(ThreadPoolTaskGroup *Group) const {  in workCompletedUnlocked()
137   if (Group == nullptr)  in workCompletedUnlocked()
139   return ActiveGroups.count(Group) == 0 &&  in workCompletedUnlocked()
141                        [Group](const auto &T) { return T.second == Group; });  in workCompletedUnlocked()
146   // Wait for all threads to complete and the queue to be empty  in wait()
152 void StdThreadPool::wait(ThreadPoolTaskGroup &Group) {  in wait()  argument
153   // Wait for all threads in the group to complete.  in wait()
157                              [&] { return workCompletedUnlocked(&Group); });  in wait()
162          !llvm::is_contained(*CurrentThreadTaskGroups, &Group));  in wait()
163   // Handle the case of recursive call from another task in a different group,  in wait()
166   processTasks(&Group);  in wait()
212   // is already removed from the queue).  in wait()