1 2 //===----------------------------------------------------------------------===// 3 // 4 // The LLVM Compiler Infrastructure 5 // 6 // This file is dual licensed under the MIT and the University of Illinois Open 7 // Source Licenses. See LICENSE.txt for details. 8 // 9 //===----------------------------------------------------------------------===// 10 11 #include "kmp.h" 12 #include "kmp_i18n.h" 13 #include "kmp_io.h" 14 #include "kmp_str.h" 15 #if OMPT_SUPPORT 16 #include "ompt-specific.h" 17 #endif 18 19 #if OMP_40_ENABLED 20 21 /*! 22 @ingroup CANCELLATION 23 @param loc_ref location of the original task directive 24 @param gtid Global thread ID of encountering thread 25 @param cncl_kind Cancellation kind (parallel, for, sections, taskgroup) 26 27 @return returns true if the cancellation request has been activated and the 28 execution thread needs to proceed to the end of the canceled region. 29 30 Request cancellation of the binding OpenMP region. 31 */ 32 kmp_int32 __kmpc_cancel(ident_t *loc_ref, kmp_int32 gtid, kmp_int32 cncl_kind) { 33 kmp_info_t *this_thr = __kmp_threads[gtid]; 34 35 KC_TRACE(10, ("__kmpc_cancel: T#%d request %d OMP_CANCELLATION=%d\n", gtid, 36 cncl_kind, __kmp_omp_cancellation)); 37 38 KMP_DEBUG_ASSERT(cncl_kind != cancel_noreq); 39 KMP_DEBUG_ASSERT(cncl_kind == cancel_parallel || cncl_kind == cancel_loop || 40 cncl_kind == cancel_sections || 41 cncl_kind == cancel_taskgroup); 42 KMP_DEBUG_ASSERT(__kmp_get_gtid() == gtid); 43 44 if (__kmp_omp_cancellation) { 45 switch (cncl_kind) { 46 case cancel_parallel: 47 case cancel_loop: 48 case cancel_sections: 49 // cancellation requests for parallel and worksharing constructs 50 // are handled through the team structure 51 { 52 kmp_team_t *this_team = this_thr->th.th_team; 53 KMP_DEBUG_ASSERT(this_team); 54 kmp_int32 old = cancel_noreq; 55 this_team->t.t_cancel_request.compare_exchange_strong(old, cncl_kind); 56 if (old == cancel_noreq || old == cncl_kind) { 57 // we do not have a cancellation request in this team or we do have 58 // one that matches the current request -> cancel 59 #if OMPT_SUPPORT && OMPT_OPTIONAL 60 if (ompt_enabled.ompt_callback_cancel) { 61 ompt_data_t *task_data; 62 __ompt_get_task_info_internal(0, NULL, &task_data, NULL, NULL, 63 NULL); 64 ompt_cancel_flag_t type = ompt_cancel_parallel; 65 if (cncl_kind == cancel_parallel) 66 type = ompt_cancel_parallel; 67 else if (cncl_kind == cancel_loop) 68 type = ompt_cancel_loop; 69 else if (cncl_kind == cancel_sections) 70 type = ompt_cancel_sections; 71 ompt_callbacks.ompt_callback(ompt_callback_cancel)( 72 task_data, type | ompt_cancel_activated, 73 OMPT_GET_RETURN_ADDRESS(0)); 74 } 75 #endif 76 return 1 /* true */; 77 } 78 break; 79 } 80 case cancel_taskgroup: 81 // cancellation requests for a task group 82 // are handled through the taskgroup structure 83 { 84 kmp_taskdata_t *task; 85 kmp_taskgroup_t *taskgroup; 86 87 task = this_thr->th.th_current_task; 88 KMP_DEBUG_ASSERT(task); 89 90 taskgroup = task->td_taskgroup; 91 if (taskgroup) { 92 kmp_int32 old = cancel_noreq; 93 taskgroup->cancel_request.compare_exchange_strong(old, cncl_kind); 94 if (old == cancel_noreq || old == cncl_kind) { 95 // we do not have a cancellation request in this taskgroup or we do 96 // have one that matches the current request -> cancel 97 #if OMPT_SUPPORT && OMPT_OPTIONAL 98 if (ompt_enabled.ompt_callback_cancel) { 99 ompt_data_t *task_data; 100 __ompt_get_task_info_internal(0, NULL, &task_data, NULL, NULL, 101 NULL); 102 ompt_callbacks.ompt_callback(ompt_callback_cancel)( 103 task_data, ompt_cancel_taskgroup | ompt_cancel_activated, 104 OMPT_GET_RETURN_ADDRESS(0)); 105 } 106 #endif 107 return 1 /* true */; 108 } 109 } else { 110 // TODO: what needs to happen here? 111 // the specification disallows cancellation w/o taskgroups 112 // so we might do anything here, let's abort for now 113 KMP_ASSERT(0 /* false */); 114 } 115 } 116 break; 117 default: 118 KMP_ASSERT(0 /* false */); 119 } 120 } 121 122 // ICV OMP_CANCELLATION=false, so we ignored this cancel request 123 KMP_DEBUG_ASSERT(!__kmp_omp_cancellation); 124 return 0 /* false */; 125 } 126 127 /*! 128 @ingroup CANCELLATION 129 @param loc_ref location of the original task directive 130 @param gtid Global thread ID of encountering thread 131 @param cncl_kind Cancellation kind (parallel, for, sections, taskgroup) 132 133 @return returns true if a matching cancellation request has been flagged in the 134 RTL and the encountering thread has to cancel.. 135 136 Cancellation point for the encountering thread. 137 */ 138 kmp_int32 __kmpc_cancellationpoint(ident_t *loc_ref, kmp_int32 gtid, 139 kmp_int32 cncl_kind) { 140 kmp_info_t *this_thr = __kmp_threads[gtid]; 141 142 KC_TRACE(10, 143 ("__kmpc_cancellationpoint: T#%d request %d OMP_CANCELLATION=%d\n", 144 gtid, cncl_kind, __kmp_omp_cancellation)); 145 146 KMP_DEBUG_ASSERT(cncl_kind != cancel_noreq); 147 KMP_DEBUG_ASSERT(cncl_kind == cancel_parallel || cncl_kind == cancel_loop || 148 cncl_kind == cancel_sections || 149 cncl_kind == cancel_taskgroup); 150 KMP_DEBUG_ASSERT(__kmp_get_gtid() == gtid); 151 152 if (__kmp_omp_cancellation) { 153 switch (cncl_kind) { 154 case cancel_parallel: 155 case cancel_loop: 156 case cancel_sections: 157 // cancellation requests for parallel and worksharing constructs 158 // are handled through the team structure 159 { 160 kmp_team_t *this_team = this_thr->th.th_team; 161 KMP_DEBUG_ASSERT(this_team); 162 if (this_team->t.t_cancel_request) { 163 if (cncl_kind == this_team->t.t_cancel_request) { 164 // the request in the team structure matches the type of 165 // cancellation point so we can cancel 166 #if OMPT_SUPPORT && OMPT_OPTIONAL 167 if (ompt_enabled.ompt_callback_cancel) { 168 ompt_data_t *task_data; 169 __ompt_get_task_info_internal(0, NULL, &task_data, NULL, NULL, 170 NULL); 171 ompt_cancel_flag_t type = ompt_cancel_parallel; 172 if (cncl_kind == cancel_parallel) 173 type = ompt_cancel_parallel; 174 else if (cncl_kind == cancel_loop) 175 type = ompt_cancel_loop; 176 else if (cncl_kind == cancel_sections) 177 type = ompt_cancel_sections; 178 ompt_callbacks.ompt_callback(ompt_callback_cancel)( 179 task_data, type | ompt_cancel_detected, 180 OMPT_GET_RETURN_ADDRESS(0)); 181 } 182 #endif 183 return 1 /* true */; 184 } 185 KMP_ASSERT(0 /* false */); 186 } else { 187 // we do not have a cancellation request pending, so we just 188 // ignore this cancellation point 189 return 0; 190 } 191 break; 192 } 193 case cancel_taskgroup: 194 // cancellation requests for a task group 195 // are handled through the taskgroup structure 196 { 197 kmp_taskdata_t *task; 198 kmp_taskgroup_t *taskgroup; 199 200 task = this_thr->th.th_current_task; 201 KMP_DEBUG_ASSERT(task); 202 203 taskgroup = task->td_taskgroup; 204 if (taskgroup) { 205 // return the current status of cancellation for the taskgroup 206 #if OMPT_SUPPORT && OMPT_OPTIONAL 207 if (ompt_enabled.ompt_callback_cancel && 208 !!taskgroup->cancel_request) { 209 ompt_data_t *task_data; 210 __ompt_get_task_info_internal(0, NULL, &task_data, NULL, NULL, 211 NULL); 212 ompt_callbacks.ompt_callback(ompt_callback_cancel)( 213 task_data, ompt_cancel_taskgroup | ompt_cancel_detected, 214 OMPT_GET_RETURN_ADDRESS(0)); 215 } 216 #endif 217 return !!taskgroup->cancel_request; 218 } else { 219 // if a cancellation point is encountered by a task that does not 220 // belong to a taskgroup, it is OK to ignore it 221 return 0 /* false */; 222 } 223 } 224 default: 225 KMP_ASSERT(0 /* false */); 226 } 227 } 228 229 // ICV OMP_CANCELLATION=false, so we ignore the cancellation point 230 KMP_DEBUG_ASSERT(!__kmp_omp_cancellation); 231 return 0 /* false */; 232 } 233 234 /*! 235 @ingroup CANCELLATION 236 @param loc_ref location of the original task directive 237 @param gtid Global thread ID of encountering thread 238 239 @return returns true if a matching cancellation request has been flagged in the 240 RTL and the encountering thread has to cancel.. 241 242 Barrier with cancellation point to send threads from the barrier to the 243 end of the parallel region. Needs a special code pattern as documented 244 in the design document for the cancellation feature. 245 */ 246 kmp_int32 __kmpc_cancel_barrier(ident_t *loc, kmp_int32 gtid) { 247 int ret = 0 /* false */; 248 kmp_info_t *this_thr = __kmp_threads[gtid]; 249 kmp_team_t *this_team = this_thr->th.th_team; 250 251 KMP_DEBUG_ASSERT(__kmp_get_gtid() == gtid); 252 253 // call into the standard barrier 254 __kmpc_barrier(loc, gtid); 255 256 // if cancellation is active, check cancellation flag 257 if (__kmp_omp_cancellation) { 258 // depending on which construct to cancel, check the flag and 259 // reset the flag 260 switch (KMP_ATOMIC_LD_RLX(&(this_team->t.t_cancel_request))) { 261 case cancel_parallel: 262 ret = 1; 263 // ensure that threads have checked the flag, when 264 // leaving the above barrier 265 __kmpc_barrier(loc, gtid); 266 this_team->t.t_cancel_request = cancel_noreq; 267 // the next barrier is the fork/join barrier, which 268 // synchronizes the threads leaving here 269 break; 270 case cancel_loop: 271 case cancel_sections: 272 ret = 1; 273 // ensure that threads have checked the flag, when 274 // leaving the above barrier 275 __kmpc_barrier(loc, gtid); 276 this_team->t.t_cancel_request = cancel_noreq; 277 // synchronize the threads again to make sure we do not have any run-away 278 // threads that cause a race on the cancellation flag 279 __kmpc_barrier(loc, gtid); 280 break; 281 case cancel_taskgroup: 282 // this case should not occur 283 KMP_ASSERT(0 /* false */); 284 break; 285 case cancel_noreq: 286 // do nothing 287 break; 288 default: 289 KMP_ASSERT(0 /* false */); 290 } 291 } 292 293 return ret; 294 } 295 296 /*! 297 @ingroup CANCELLATION 298 @param loc_ref location of the original task directive 299 @param gtid Global thread ID of encountering thread 300 301 @return returns true if a matching cancellation request has been flagged in the 302 RTL and the encountering thread has to cancel.. 303 304 Query function to query the current status of cancellation requests. 305 Can be used to implement the following pattern: 306 307 if (kmp_get_cancellation_status(kmp_cancel_parallel)) { 308 perform_cleanup(); 309 #pragma omp cancellation point parallel 310 } 311 */ 312 int __kmp_get_cancellation_status(int cancel_kind) { 313 if (__kmp_omp_cancellation) { 314 kmp_info_t *this_thr = __kmp_entry_thread(); 315 316 switch (cancel_kind) { 317 case cancel_parallel: 318 case cancel_loop: 319 case cancel_sections: { 320 kmp_team_t *this_team = this_thr->th.th_team; 321 return this_team->t.t_cancel_request == cancel_kind; 322 } 323 case cancel_taskgroup: { 324 kmp_taskdata_t *task; 325 kmp_taskgroup_t *taskgroup; 326 task = this_thr->th.th_current_task; 327 taskgroup = task->td_taskgroup; 328 return taskgroup && taskgroup->cancel_request; 329 } 330 } 331 } 332 333 return 0 /* false */; 334 } 335 336 #endif 337