1 2 /* 3 Some PETSc utilites 4 */ 5 #include <petscsys.h> /*I "petscsys.h" I*/ 6 #if defined(PETSC_HAVE_STDLIB_H) 7 #include <stdlib.h> 8 #endif 9 10 #include <petsc-private/threadcommimpl.h> 11 /* ---------------------------------------------------------------- */ 12 /* 13 A simple way to manage tags inside a communicator. 14 15 It uses the attributes to determine if a new communicator 16 is needed and to store the available tags. 17 18 */ 19 20 21 #undef __FUNCT__ 22 #define __FUNCT__ "PetscObjectGetNewTag" 23 /*@C 24 PetscObjectGetNewTag - Gets a unique new tag from a PETSc object. All 25 processors that share the object MUST call this routine EXACTLY the same 26 number of times. This tag should only be used with the current objects 27 communicator; do NOT use it with any other MPI communicator. 28 29 Collective on PetscObject 30 31 Input Parameter: 32 . obj - the PETSc object; this must be cast with a (PetscObject), for example, 33 PetscObjectGetNewTag((PetscObject)mat,&tag); 34 35 Output Parameter: 36 . tag - the new tag 37 38 Level: developer 39 40 Concepts: tag^getting 41 Concepts: message tag^getting 42 Concepts: MPI message tag^getting 43 44 .seealso: PetscCommGetNewTag() 45 @*/ 46 PetscErrorCode PetscObjectGetNewTag(PetscObject obj,PetscMPIInt *tag) 47 { 48 PetscErrorCode ierr; 49 50 PetscFunctionBegin; 51 ierr = PetscCommGetNewTag(obj->comm,tag);CHKERRQ(ierr); 52 PetscFunctionReturn(0); 53 } 54 55 #undef __FUNCT__ 56 #define __FUNCT__ "PetscCommGetNewTag" 57 /*@ 58 PetscCommGetNewTag - Gets a unique new tag from a PETSc communicator. All 59 processors that share the communicator MUST call this routine EXACTLY the same 60 number of times. This tag should only be used with the current objects 61 communicator; do NOT use it with any other MPI communicator. 62 63 Collective on comm 64 65 Input Parameter: 66 . comm - the MPI communicator 67 68 Output Parameter: 69 . tag - the new tag 70 71 Level: developer 72 73 Concepts: tag^getting 74 Concepts: message tag^getting 75 Concepts: MPI message tag^getting 76 77 .seealso: PetscObjectGetNewTag(), PetscCommDuplicate() 78 @*/ 79 PetscErrorCode PetscCommGetNewTag(MPI_Comm comm,PetscMPIInt *tag) 80 { 81 PetscErrorCode ierr; 82 PetscCommCounter *counter; 83 PetscMPIInt *maxval,flg; 84 85 PetscFunctionBegin; 86 PetscValidIntPointer(tag,2); 87 88 ierr = MPI_Attr_get(comm,Petsc_Counter_keyval,&counter,&flg);CHKERRQ(ierr); 89 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"Bad MPI communicator supplied; must be a PETSc communicator"); 90 91 if (counter->tag < 1) { 92 ierr = PetscInfo1(0,"Out of tags for object, starting to recycle. Comm reference count %d\n",counter->refcount);CHKERRQ(ierr); 93 ierr = MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,&maxval,&flg);CHKERRQ(ierr); 94 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB"); 95 counter->tag = *maxval - 128; /* hope that any still active tags were issued right at the beginning of the run */ 96 } 97 98 *tag = counter->tag--; 99 #if defined(PETSC_USE_DEBUG) 100 /* 101 Hanging here means that some processes have called PetscCommGetNewTag() and others have not. 102 */ 103 ierr = MPI_Barrier(comm);CHKERRQ(ierr); 104 #endif 105 PetscFunctionReturn(0); 106 } 107 108 #undef __FUNCT__ 109 #define __FUNCT__ "PetscCommDuplicate" 110 /*@C 111 PetscCommDuplicate - Duplicates the communicator only if it is not already a PETSc communicator. 112 113 Collective on MPI_Comm 114 115 Input Parameters: 116 . comm_in - Input communicator 117 118 Output Parameters: 119 + comm_out - Output communicator. May be comm_in. 120 - first_tag - Tag available that has not already been used with this communicator (you may 121 pass in PETSC_NULL if you do not need a tag) 122 123 PETSc communicators are just regular MPI communicators that keep track of which 124 tags have been used to prevent tag conflict. If you pass a non-PETSc communicator into 125 a PETSc creation routine it will attach a private communicator for use in the objects communications. 126 The internal MPI_Comm is used to perform all the MPI calls for PETSc, the outer MPI_Comm is a user 127 level MPI_Comm that may be performing communication for the user or other library and so IS NOT used by PETSc. 128 129 Level: developer 130 131 Concepts: communicator^duplicate 132 133 .seealso: PetscObjectGetNewTag(), PetscCommGetNewTag(), PetscCommDestroy() 134 @*/ 135 PetscErrorCode PetscCommDuplicate(MPI_Comm comm_in,MPI_Comm *comm_out,PetscMPIInt* first_tag) 136 { 137 PetscErrorCode ierr; 138 PetscCommCounter *counter; 139 PetscMPIInt *maxval,flg; 140 PetscThreadComm tcomm; 141 142 PetscFunctionBegin; 143 ierr = MPI_Attr_get(comm_in,Petsc_Counter_keyval,&counter,&flg);CHKERRQ(ierr); 144 145 if (!flg) { /* this is NOT a PETSc comm */ 146 void *ptr; 147 /* check if this communicator has a PETSc communicator imbedded in it */ 148 ierr = MPI_Attr_get(comm_in,Petsc_InnerComm_keyval,&ptr,&flg);CHKERRQ(ierr); 149 if (!flg) { 150 /* This communicator is not yet known to this system, so we duplicate it and make an internal communicator */ 151 ierr = MPI_Comm_dup(comm_in,comm_out);CHKERRQ(ierr); 152 ierr = MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,&maxval,&flg);CHKERRQ(ierr); 153 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB"); 154 ierr = PetscMalloc(sizeof(PetscCommCounter),&counter);CHKERRQ(ierr); 155 counter->tag = *maxval; 156 counter->refcount = 0; 157 counter->namecount = 0; 158 ierr = MPI_Attr_put(*comm_out,Petsc_Counter_keyval,counter);CHKERRQ(ierr); 159 ierr = PetscInfo3(0,"Duplicating a communicator %ld %ld max tags = %d\n",(long)comm_in,(long)*comm_out,*maxval);CHKERRQ(ierr); 160 161 /* save PETSc communicator inside user communicator, so we can get it next time */ 162 /* Use PetscMemcpy() because casting from pointer to integer of different size is not allowed with some compilers */ 163 ierr = PetscMemcpy(&ptr,comm_out,sizeof(MPI_Comm));CHKERRQ(ierr); 164 ierr = MPI_Attr_put(comm_in,Petsc_InnerComm_keyval,ptr);CHKERRQ(ierr); 165 /* Use PetscMemcpy() because casting from pointer to integer of different size is not allowed with some compilers */ 166 ierr = PetscMemcpy(&ptr,&comm_in,sizeof(MPI_Comm));CHKERRQ(ierr); 167 ierr = MPI_Attr_put(*comm_out,Petsc_OuterComm_keyval,ptr);CHKERRQ(ierr); 168 } else { 169 /* pull out the inner MPI_Comm and hand it back to the caller */ 170 /* Use PetscMemcpy() because casting from pointer to integer of different size is not allowed with some compilers */ 171 ierr = PetscMemcpy(comm_out,&ptr,sizeof(MPI_Comm));CHKERRQ(ierr); 172 ierr = MPI_Attr_get(*comm_out,Petsc_Counter_keyval,&counter,&flg);CHKERRQ(ierr); 173 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Inner PETSc communicator does not have its tag/name counter attribute set"); 174 ierr = PetscInfo2(0,"Using internal PETSc communicator %ld %ld\n",(long)comm_in,(long)*comm_out);CHKERRQ(ierr); 175 } 176 } else { 177 *comm_out = comm_in; 178 } 179 180 #if defined(PETSC_USE_DEBUG) 181 /* 182 Hanging here means that some processes have called PetscCommDuplicate() and others have not. 183 This likley means that a subset of processes in a MPI_Comm have attempted to create a PetscObject! 184 ALL processes that share a communicator MUST shared objects created from that communicator. 185 */ 186 ierr = MPI_Barrier(comm_in);CHKERRQ(ierr); 187 #endif 188 189 if (counter->tag < 1) { 190 ierr = PetscInfo1(0,"Out of tags for object, starting to recycle. Comm reference count %d\n",counter->refcount);CHKERRQ(ierr); 191 ierr = MPI_Attr_get(MPI_COMM_WORLD,MPI_TAG_UB,&maxval,&flg);CHKERRQ(ierr); 192 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"MPI error: MPI_Attr_get() is not returning a MPI_TAG_UB"); 193 counter->tag = *maxval - 128; /* hope that any still active tags were issued right at the beginning of the run */ 194 } 195 196 if (first_tag) { 197 *first_tag = counter->tag--; 198 } 199 200 /* Only the main thread updates counter->refcount */ 201 ierr = MPI_Attr_get(*comm_out,Petsc_ThreadComm_keyval,(PetscThreadComm*)&tcomm,&flg);CHKERRQ(ierr); 202 if (flg) { 203 PetscInt trank; 204 ierr = PetscThreadCommGetRank(tcomm,&trank); 205 if (!trank) counter->refcount++; /* number of references to this comm */ 206 } else counter->refcount++; 207 208 PetscFunctionReturn(0); 209 } 210 211 #undef __FUNCT__ 212 #define __FUNCT__ "PetscCommDestroy" 213 /*@C 214 PetscCommDestroy - Frees communicator. Use in conjunction with PetscCommDuplicate(). 215 216 Collective on MPI_Comm 217 218 Input Parameter: 219 . comm - the communicator to free 220 221 Level: developer 222 223 Concepts: communicator^destroy 224 225 .seealso: PetscCommDuplicate() 226 @*/ 227 PetscErrorCode PetscCommDestroy(MPI_Comm *comm) 228 { 229 PetscErrorCode ierr; 230 PetscCommCounter *counter; 231 PetscMPIInt flg; 232 MPI_Comm icomm = *comm,ocomm; 233 void *ptr; 234 PetscThreadComm tcomm; 235 236 PetscFunctionBegin; 237 if (*comm == MPI_COMM_NULL) PetscFunctionReturn(0); 238 ierr = MPI_Attr_get(icomm,Petsc_Counter_keyval,&counter,&flg);CHKERRQ(ierr); 239 if (!flg) { /* not a PETSc comm, check if it has an inner comm */ 240 ierr = MPI_Attr_get(icomm,Petsc_InnerComm_keyval,&ptr,&flg);CHKERRQ(ierr); 241 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"MPI_Comm does not have tag/name counter nor does it have inner MPI_Comm"); 242 /* Use PetscMemcpy() because casting from pointer to integer of different size is not allowed with some compilers */ 243 ierr = PetscMemcpy(&icomm,&ptr,sizeof(MPI_Comm));CHKERRQ(ierr); 244 ierr = MPI_Attr_get(icomm,Petsc_Counter_keyval,&counter,&flg);CHKERRQ(ierr); 245 if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"Inner MPI_Comm does not have expected tag/name counter, problem with corrupted memory"); 246 } 247 248 /* Only the main thread updates counter->refcount */ 249 ierr = MPI_Attr_get(icomm,Petsc_ThreadComm_keyval,(PetscThreadComm*)&tcomm,&flg);CHKERRQ(ierr); 250 if (flg) { 251 PetscInt trank; 252 ierr = PetscThreadCommGetRank(tcomm,&trank); 253 /* Only thread rank 0 updates the counter */ 254 if (!trank) counter->refcount--; 255 } else counter->refcount--; 256 257 if (!counter->refcount) { 258 /* if MPI_Comm has outer comm then remove reference to inner MPI_Comm from outer MPI_Comm */ 259 ierr = MPI_Attr_get(icomm,Petsc_OuterComm_keyval,&ptr,&flg);CHKERRQ(ierr); 260 if (flg) { 261 /* Use PetscMemcpy() because casting from pointer to integer of different size is not allowed with some compilers */ 262 ierr = PetscMemcpy(&ocomm,&ptr,sizeof(MPI_Comm));CHKERRQ(ierr); 263 ierr = MPI_Attr_get(ocomm,Petsc_InnerComm_keyval,&ptr,&flg);CHKERRQ(ierr); 264 if (flg) { 265 ierr = MPI_Attr_delete(ocomm,Petsc_InnerComm_keyval);CHKERRQ(ierr); 266 } else SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_CORRUPT,"Outer MPI_Comm %ld does not have expected reference to inner comm %d, problem with corrupted memory",(long int)ocomm,(long int)icomm); 267 } 268 269 ierr = PetscInfo1(0,"Deleting PETSc MPI_Comm %ld\n",(long)icomm);CHKERRQ(ierr); 270 ierr = MPI_Comm_free(&icomm);CHKERRQ(ierr); 271 } 272 *comm = MPI_COMM_NULL; 273 PetscFunctionReturn(0); 274 } 275 276 #undef __FUNCT__ 277 #define __FUNCT__ "PetscObjectsGetGlobalNumbering" 278 /*@C 279 PetscObjectsGetGlobalNumbering - computes a global numbering 280 of PetscObjects living on subcommunicators of a given communicator. 281 This results in a deadlock-free ordering of the subcommunicators 282 and, hence, the objects. 283 284 285 Collective on comm. 286 287 Input Parameters: 288 + comm - MPI_Comm 289 . len - length of objlist 290 - objlist - a list of PETSc objects living on subcommunicators of comm 291 (subcommunicator ordering is assumed to be deadlock-free) 292 293 Output Parameters: 294 + count - number of globally-distinct subcommunicators on objlist 295 . numbering - global numbers of objlist entries (allocated by user) 296 297 298 Level: developer 299 300 Concepts: MPI subcomm^numbering 301 302 @*/ 303 PetscErrorCode PetscObjectsGetGlobalNumbering(MPI_Comm comm, PetscInt len, PetscObject *objlist, PetscInt *count, PetscInt *numbering) 304 { 305 PetscErrorCode ierr; 306 PetscInt i, roots, offset; 307 PetscMPIInt size, rank; 308 PetscFunctionBegin; 309 PetscValidPointer(objlist,3); 310 PetscValidPointer(count,4); 311 PetscValidPointer(numbering,5); 312 ierr = MPI_Comm_size(comm, &size); CHKERRQ(ierr); 313 ierr = MPI_Comm_rank(comm, &rank); CHKERRQ(ierr); 314 roots = 0; 315 for (i = 0; i < len; ++i) { 316 PetscMPIInt srank; 317 ierr = MPI_Comm_rank(objlist[i]->comm, &srank); CHKERRQ(ierr); 318 /* Am I the root of the i-th subcomm? */ 319 if (!srank) ++roots; 320 } 321 /* Obtain the sum of all roots -- the global number of distinct subcomms. */ 322 ierr = MPI_Allreduce((void*)&roots,(void*)count,1,MPIU_INT,MPI_SUM,comm); CHKERRQ(ierr); 323 /* Now introduce a global numbering for subcomms, initially known only by subcomm roots. */ 324 /* 325 At the subcomm roots number the subcomms in the subcomm-root local manner, 326 and make it global by calculating the shift. 327 */ 328 ierr = MPI_Scan((PetscMPIInt*)&roots,(PetscMPIInt*)&offset,1,MPIU_INT,MPI_SUM,comm); CHKERRQ(ierr); 329 offset -= roots; 330 /* Now we are ready to broadcast global subcomm numbers within each subcomm.*/ 331 /* 332 This is where the assumption of a deadlock-free ordering of the subcomms is assumed: 333 broadcast is collective on the subcomm. 334 */ 335 roots = 0; 336 for (i = 0; i < len; ++i) { 337 PetscMPIInt srank; 338 numbering[i] = offset + roots; /* only meaningful if !srank. */ 339 ierr = MPI_Comm_rank(objlist[i]->comm, &srank); CHKERRQ(ierr); 340 ierr = MPI_Bcast(numbering+i,1,MPIU_INT,0,objlist[i]->comm); CHKERRQ(ierr); 341 if (!srank) ++roots; 342 } 343 344 PetscFunctionReturn(0); 345 } 346