xref: /oneTBB/src/tbb/governor.h (revision c4568449)
1 /*
2     Copyright (c) 2005-2023 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_governor_H
18 #define _TBB_governor_H
19 
20 #include "rml_tbb.h"
21 
22 #include "misc.h" // for AvailableHwConcurrency
23 #include "tls.h"
24 
25 namespace tbb {
26 namespace detail {
27 namespace r1 {
28 
29 class market;
30 class thread_data;
31 class __TBB_InitOnce;
32 
33 #if __TBB_USE_ITT_NOTIFY
34 //! Defined in profiling.cpp
35 extern bool ITT_Present;
36 #endif
37 
38 typedef std::size_t stack_size_type;
39 
40 //------------------------------------------------------------------------
41 // Class governor
42 //------------------------------------------------------------------------
43 
44 //! The class handles access to the single instance of market, and to TLS to keep scheduler instances.
45 /** It also supports automatic on-demand initialization of the TBB scheduler.
46     The class contains only static data members and methods.*/
47 class governor {
48 private:
49     friend class __TBB_InitOnce;
50     friend class thread_dispatcher;
51     friend class threading_control_impl;
52 
53     // TODO: consider using thread_local (measure performance and side effects)
54     //! TLS for scheduler instances associated with individual threads
55     static basic_tls<thread_data*> theTLS;
56 
57     // TODO (TBB_REVAMP_TODO): reconsider constant names
58     static rml::tbb_factory theRMLServerFactory;
59 
60     static bool UsePrivateRML;
61 
62     // Flags for runtime-specific conditions
63     static cpu_features_type cpu_features;
64     static bool is_rethrow_broken;
65 
66     //! Create key for thread-local storage and initialize RML.
67     static void acquire_resources ();
68 
69     //! Destroy the thread-local storage key and deinitialize RML.
70     static void release_resources ();
71 
72     static rml::tbb_server* create_rml_server ( rml::tbb_client& );
73 
74 public:
default_num_threads()75     static unsigned default_num_threads () {
76         // Caches the maximal level of parallelism supported by the hardware
77         static unsigned num_threads = AvailableHwConcurrency();
78         return num_threads;
79     }
default_page_size()80     static std::size_t default_page_size () {
81         // Caches the size of OS regular memory page
82         static std::size_t page_size = DefaultSystemPageSize();
83         return page_size;
84     }
85     static void one_time_init();
86     //! Processes scheduler initialization request (possibly nested) in an external thread
87     /** If necessary creates new instance of arena and/or local scheduler.
88         The auto_init argument specifies if the call is due to automatic initialization. **/
89     static void init_external_thread();
90 
91     //! The routine to undo automatic initialization.
92     /** The signature is written with void* so that the routine
93         can be the destructor argument to pthread_key_create. */
94     static void auto_terminate(void* tls);
95 
96     //! Obtain the thread-local instance of the thread data.
97     /** If the scheduler has not been initialized yet, initialization is done automatically.
98         Note that auto-initialized scheduler instance is destroyed only when its thread terminates. **/
get_thread_data()99     static thread_data* get_thread_data() {
100         thread_data* td = theTLS.get();
101         if (td) {
102             return td;
103         }
104         init_external_thread();
105         td = theTLS.get();
106         __TBB_ASSERT(td, nullptr);
107         return td;
108     }
109 
set_thread_data(thread_data & td)110     static void set_thread_data(thread_data& td) {
111         theTLS.set(&td);
112     }
113 
clear_thread_data()114     static void clear_thread_data() {
115         theTLS.set(nullptr);
116     }
117 
get_thread_data_if_initialized()118     static thread_data* get_thread_data_if_initialized () {
119         return theTLS.get();
120     }
121 
is_thread_data_set(thread_data * td)122     static bool is_thread_data_set(thread_data* td) {
123         return theTLS.get() == td;
124     }
125 
126     //! Undo automatic initialization if necessary; call when a thread exits.
terminate_external_thread()127     static void terminate_external_thread() {
128         auto_terminate(get_thread_data_if_initialized());
129     }
130 
131     static void initialize_rml_factory ();
132 
133     static bool does_client_join_workers (const rml::tbb_client &client);
134 
speculation_enabled()135     static bool speculation_enabled() { return cpu_features.rtm_enabled; }
136 
137 #if __TBB_WAITPKG_INTRINSICS_PRESENT
wait_package_enabled()138     static bool wait_package_enabled() { return cpu_features.waitpkg_enabled; }
139 #endif
140 
rethrow_exception_broken()141     static bool rethrow_exception_broken() { return is_rethrow_broken; }
142 
is_itt_present()143     static bool is_itt_present() {
144 #if __TBB_USE_ITT_NOTIFY
145         return ITT_Present;
146 #else
147         return false;
148 #endif
149     }
150 }; // class governor
151 
152 } // namespace r1
153 } // namespace detail
154 } // namespace tbb
155 
156 #endif /* _TBB_governor_H */
157