xref: /oneTBB/src/tbb/thread_data.h (revision 2eccd5f9)
1 /*
2     Copyright (c) 2020-2022 Intel Corporation
3 
4     Licensed under the Apache License, Version 2.0 (the "License");
5     you may not use this file except in compliance with the License.
6     You may obtain a copy of the License at
7 
8         http://www.apache.org/licenses/LICENSE-2.0
9 
10     Unless required by applicable law or agreed to in writing, software
11     distributed under the License is distributed on an "AS IS" BASIS,
12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13     See the License for the specific language governing permissions and
14     limitations under the License.
15 */
16 
17 #ifndef __TBB_thread_data_H
18 #define __TBB_thread_data_H
19 
20 #include "oneapi/tbb/detail/_task.h"
21 #include "oneapi/tbb/task.h"
22 
23 #include "rml_base.h" // rml::job
24 
25 #include "scheduler_common.h"
26 #include "arena.h"
27 #include "concurrent_monitor.h"
28 #include "mailbox.h"
29 #include "misc.h" // FastRandom
30 #include "small_object_pool_impl.h"
31 
32 #include <atomic>
33 
34 namespace tbb {
35 namespace detail {
36 namespace r1 {
37 
38 class task;
39 class arena_slot;
40 class task_group_context;
41 class task_dispatcher;
42 
43 class context_list : public intrusive_list<intrusive_list_node> {
44 public:
45     bool orphaned{false};
46 
47     //! Last state propagation epoch known to this thread
48     /** Together with the_context_state_propagation_epoch constitute synchronization protocol
49     that keeps hot path of task group context construction destruction mostly
50     lock-free.
51     When local epoch equals the global one, the state of task group contexts
52     registered with this thread is consistent with that of the task group trees
53     they belong to. **/
54     std::atomic<std::uintptr_t> epoch{};
55 
56     //! Mutex protecting access to the list of task group contexts.
57     d1::mutex m_mutex{};
58 
59     void destroy() {
60         this->~context_list();
61         cache_aligned_deallocate(this);
62     }
63 
64     void remove(intrusive_list_node& val) {
65         mutex::scoped_lock lock(m_mutex);
66 
67         intrusive_list<intrusive_list_node>::remove(val);
68 
69         if (orphaned && empty()) {
70             lock.release();
71             destroy();
72         }
73     }
74 
75     void push_front(intrusive_list_node& val) {
76         mutex::scoped_lock lock(m_mutex);
77 
78         intrusive_list<intrusive_list_node>::push_front(val);
79     }
80 
81     void orphan() {
82         mutex::scoped_lock lock(m_mutex);
83 
84         orphaned = true;
85         if (empty()) {
86             lock.release();
87             destroy();
88         }
89     }
90 };
91 
92 //------------------------------------------------------------------------
93 // Thread Data
94 //------------------------------------------------------------------------
95 class thread_data : public ::rml::job
96                   , public intrusive_list_node
97                   , no_copy {
98 public:
99     thread_data(unsigned short index, bool is_worker)
100         : my_arena_index{ index }
101         , my_is_worker{ is_worker }
102         , my_task_dispatcher{ nullptr }
103         , my_arena{}
104         , my_arena_slot{}
105         , my_random{ this }
106         , my_last_observer{ nullptr }
107         , my_small_object_pool{new (cache_aligned_allocate(sizeof(small_object_pool_impl))) small_object_pool_impl{}}
108         , my_context_list(new (cache_aligned_allocate(sizeof(context_list))) context_list{})
109 #if __TBB_RESUMABLE_TASKS
110         , my_post_resume_action{ task_dispatcher::post_resume_action::none }
111         , my_post_resume_arg{nullptr}
112 #endif /* __TBB_RESUMABLE_TASKS */
113     {
114         ITT_SYNC_CREATE(&my_context_list->m_mutex, SyncType_Scheduler, SyncObj_ContextsList);
115     }
116 
117     ~thread_data() {
118         my_context_list->orphan();
119         my_small_object_pool->destroy();
120         poison_pointer(my_task_dispatcher);
121         poison_pointer(my_arena);
122         poison_pointer(my_arena_slot);
123         poison_pointer(my_last_observer);
124         poison_pointer(my_small_object_pool);
125         poison_pointer(my_context_list);
126 #if __TBB_RESUMABLE_TASKS
127         poison_pointer(my_post_resume_arg);
128 #endif /* __TBB_RESUMABLE_TASKS */
129     }
130 
131     void attach_arena(arena& a, std::size_t index);
132     bool is_attached_to(arena*);
133     void attach_task_dispatcher(task_dispatcher&);
134     void detach_task_dispatcher();
135     void enter_task_dispatcher(task_dispatcher& task_disp, std::uintptr_t stealing_threshold);
136     void leave_task_dispatcher();
137     template <typename T>
138     void propagate_task_group_state(std::atomic<T> d1::task_group_context::* mptr_state, d1::task_group_context& src, T new_state);
139 
140     //! Index of the arena slot the scheduler occupies now, or occupied last time
141     unsigned short my_arena_index;
142 
143     //! Indicates if the thread is created by RML
144     const bool my_is_worker;
145 
146     //! The current task dipsatcher
147     task_dispatcher* my_task_dispatcher;
148 
149     //! The arena that I own (if external thread) or am servicing at the moment (if worker)
150     arena* my_arena;
151 
152     //! Pointer to the slot in the arena we own at the moment
153     arena_slot* my_arena_slot;
154 
155     //! The mailbox (affinity mechanism) the current thread attached to
156     mail_inbox my_inbox;
157 
158     //! The random generator
159     FastRandom my_random;
160 
161     //! Last observer in the observers list processed on this slot
162     observer_proxy* my_last_observer;
163 
164     //! Pool of small object for fast task allocation
165     small_object_pool_impl* my_small_object_pool;
166 
167     context_list* my_context_list;
168 #if __TBB_RESUMABLE_TASKS
169     //! Suspends the current coroutine (task_dispatcher).
170     void suspend(void* suspend_callback, void* user_callback);
171 
172     //! Resumes the target task_dispatcher.
173     void resume(task_dispatcher& target);
174 
175     //! Set post resume action to perform after resume.
176     void set_post_resume_action(task_dispatcher::post_resume_action pra, void* arg) {
177         __TBB_ASSERT(my_post_resume_action == task_dispatcher::post_resume_action::none, "The Post resume action must not be set");
178         __TBB_ASSERT(!my_post_resume_arg, "The post resume action must not have an argument");
179         my_post_resume_action = pra;
180         my_post_resume_arg = arg;
181     }
182 
183     void clear_post_resume_action() {
184         my_post_resume_action = task_dispatcher::post_resume_action::none;
185         my_post_resume_arg = nullptr;
186     }
187 
188     //! The post resume action requested after the swap contexts.
189     task_dispatcher::post_resume_action my_post_resume_action;
190 
191     //! The post resume action argument.
192     void* my_post_resume_arg;
193 #endif /* __TBB_RESUMABLE_TASKS */
194 
195     //! The default context
196     // TODO: consider using common default context because it is used only to simplify
197     // cancellation check.
198     d1::task_group_context my_default_context;
199 };
200 
201 inline void thread_data::attach_arena(arena& a, std::size_t index) {
202     my_arena = &a;
203     my_arena_index = static_cast<unsigned short>(index);
204     my_arena_slot = a.my_slots + index;
205     // Read the current slot mail_outbox and attach it to the mail_inbox (remove inbox later maybe)
206     my_inbox.attach(my_arena->mailbox(index));
207 }
208 
209 inline bool thread_data::is_attached_to(arena* a) { return my_arena == a; }
210 
211 inline void thread_data::attach_task_dispatcher(task_dispatcher& task_disp) {
212     __TBB_ASSERT(my_task_dispatcher == nullptr, nullptr);
213     __TBB_ASSERT(task_disp.m_thread_data == nullptr, nullptr);
214     task_disp.m_thread_data = this;
215     my_task_dispatcher = &task_disp;
216 }
217 
218 inline void thread_data::detach_task_dispatcher() {
219     __TBB_ASSERT(my_task_dispatcher != nullptr, nullptr);
220     __TBB_ASSERT(my_task_dispatcher->m_thread_data == this, nullptr);
221     my_task_dispatcher->m_thread_data = nullptr;
222     my_task_dispatcher = nullptr;
223 }
224 
225 inline void thread_data::enter_task_dispatcher(task_dispatcher& task_disp, std::uintptr_t stealing_threshold) {
226     task_disp.set_stealing_threshold(stealing_threshold);
227     attach_task_dispatcher(task_disp);
228 }
229 
230 inline void thread_data::leave_task_dispatcher() {
231     my_task_dispatcher->set_stealing_threshold(0);
232     detach_task_dispatcher();
233 }
234 
235 } // namespace r1
236 } // namespace detail
237 } // namespace tbb
238 
239 #endif // __TBB_thread_data_H
240 
241