1 #include <petscsys.h> /*I "petscsys.h" I*/ 2 3 PetscLogEvent PETSC_BuildTwoSided; 4 5 const char *const PetscBuildTwoSidedTypes[] = { 6 "ALLREDUCE", 7 "IBARRIER", 8 "REDSCATTER", 9 "PetscBuildTwoSidedType", 10 "PETSC_BUILDTWOSIDED_", 11 0 12 }; 13 14 static PetscBuildTwoSidedType _twosided_type = PETSC_BUILDTWOSIDED_NOTSET; 15 16 #undef __FUNCT__ 17 #define __FUNCT__ "PetscCommBuildTwoSidedSetType" 18 /*@ 19 PetscCommBuildTwoSidedSetType - set algorithm to use when building two-sided communication 20 21 Logically Collective 22 23 Input Arguments: 24 + comm - PETSC_COMM_WORLD 25 - twosided - algorithm to use in subsequent calls to PetscCommBuildTwoSided() 26 27 Level: developer 28 29 Note: 30 This option is currently global, but could be made per-communicator. 31 32 .seealso: PetscCommBuildTwoSided(), PetscCommBuildTwoSidedGetType() 33 @*/ 34 PetscErrorCode PetscCommBuildTwoSidedSetType(MPI_Comm comm,PetscBuildTwoSidedType twosided) 35 { 36 PetscFunctionBegin; 37 #if defined(PETSC_USE_DEBUG) 38 { /* We don't have a PetscObject so can't use PetscValidLogicalCollectiveEnum */ 39 PetscMPIInt ierr; 40 PetscMPIInt b1[2],b2[2]; 41 b1[0] = -(PetscMPIInt)twosided; 42 b1[1] = (PetscMPIInt)twosided; 43 ierr = MPI_Allreduce(b1,b2,2,MPI_INT,MPI_MAX,comm);CHKERRQ(ierr); 44 if (-b2[0] != b2[1]) SETERRQ(comm,PETSC_ERR_ARG_WRONG,"Enum value must be same on all processes"); 45 } 46 #endif 47 _twosided_type = twosided; 48 PetscFunctionReturn(0); 49 } 50 51 #undef __FUNCT__ 52 #define __FUNCT__ "PetscCommBuildTwoSidedGetType" 53 /*@ 54 PetscCommBuildTwoSidedGetType - set algorithm to use when building two-sided communication 55 56 Logically Collective 57 58 Output Arguments: 59 + comm - communicator on which to query algorithm 60 - twosided - algorithm to use for PetscCommBuildTwoSided() 61 62 Level: developer 63 64 .seealso: PetscCommBuildTwoSided(), PetscCommBuildTwoSidedSetType() 65 @*/ 66 PetscErrorCode PetscCommBuildTwoSidedGetType(MPI_Comm comm,PetscBuildTwoSidedType *twosided) 67 { 68 PetscErrorCode ierr; 69 70 PetscFunctionBegin; 71 *twosided = PETSC_BUILDTWOSIDED_NOTSET; 72 if (_twosided_type == PETSC_BUILDTWOSIDED_NOTSET) { 73 #if defined(PETSC_HAVE_MPI_IBARRIER) 74 # if defined(PETSC_HAVE_MPICH_CH3_SOCK) && !defined(PETSC_HAVE_MPICH_CH3_SOCK_FIXED_NBC_PROGRESS) 75 /* Deadlock in Ibarrier: http://trac.mpich.org/projects/mpich/ticket/1785 */ 76 _twosided_type = PETSC_BUILDTWOSIDED_ALLREDUCE; 77 # else 78 _twosided_type = PETSC_BUILDTWOSIDED_IBARRIER; 79 # endif 80 #else 81 _twosided_type = PETSC_BUILDTWOSIDED_ALLREDUCE; 82 #endif 83 ierr = PetscOptionsGetEnum(NULL,"-build_twosided",PetscBuildTwoSidedTypes,(PetscEnum*)&_twosided_type,NULL);CHKERRQ(ierr); 84 } 85 *twosided = _twosided_type; 86 PetscFunctionReturn(0); 87 } 88 89 #if defined(PETSC_HAVE_MPI_IBARRIER) 90 91 #undef __FUNCT__ 92 #define __FUNCT__ "PetscCommBuildTwoSided_Ibarrier" 93 static PetscErrorCode PetscCommBuildTwoSided_Ibarrier(MPI_Comm comm,PetscMPIInt count,MPI_Datatype dtype,PetscMPIInt nto,const PetscMPIInt *toranks,const void *todata,PetscMPIInt *nfrom,PetscMPIInt **fromranks,void *fromdata) 94 { 95 PetscErrorCode ierr; 96 PetscMPIInt nrecvs,tag,done,i; 97 MPI_Aint lb,unitbytes; 98 char *tdata; 99 MPI_Request *sendreqs,barrier; 100 PetscSegBuffer segrank,segdata; 101 102 PetscFunctionBegin; 103 ierr = PetscCommDuplicate(comm,&comm,&tag);CHKERRQ(ierr); 104 ierr = MPI_Type_get_extent(dtype,&lb,&unitbytes);CHKERRQ(ierr); 105 if (lb != 0) SETERRQ1(comm,PETSC_ERR_SUP,"Datatype with nonzero lower bound %ld\n",(long)lb); 106 tdata = (char*)todata; 107 ierr = PetscMalloc1(nto,&sendreqs);CHKERRQ(ierr); 108 for (i=0; i<nto; i++) { 109 ierr = MPI_Issend((void*)(tdata+count*unitbytes*i),count,dtype,toranks[i],tag,comm,sendreqs+i);CHKERRQ(ierr); 110 } 111 ierr = PetscSegBufferCreate(sizeof(PetscMPIInt),4,&segrank);CHKERRQ(ierr); 112 ierr = PetscSegBufferCreate(unitbytes,4*count,&segdata);CHKERRQ(ierr); 113 114 nrecvs = 0; 115 barrier = MPI_REQUEST_NULL; 116 for (done=0; !done; ) { 117 PetscMPIInt flag; 118 MPI_Status status; 119 ierr = MPI_Iprobe(MPI_ANY_SOURCE,tag,comm,&flag,&status);CHKERRQ(ierr); 120 if (flag) { /* incoming message */ 121 PetscMPIInt *recvrank; 122 void *buf; 123 ierr = PetscSegBufferGet(segrank,1,&recvrank);CHKERRQ(ierr); 124 ierr = PetscSegBufferGet(segdata,count,&buf);CHKERRQ(ierr); 125 *recvrank = status.MPI_SOURCE; 126 ierr = MPI_Recv(buf,count,dtype,status.MPI_SOURCE,tag,comm,MPI_STATUS_IGNORE);CHKERRQ(ierr); 127 nrecvs++; 128 } 129 if (barrier == MPI_REQUEST_NULL) { 130 PetscMPIInt sent,nsends; 131 ierr = PetscMPIIntCast(nto,&nsends);CHKERRQ(ierr); 132 ierr = MPI_Testall(nsends,sendreqs,&sent,MPI_STATUSES_IGNORE);CHKERRQ(ierr); 133 if (sent) { 134 ierr = MPI_Ibarrier(comm,&barrier);CHKERRQ(ierr); 135 ierr = PetscFree(sendreqs);CHKERRQ(ierr); 136 } 137 } else { 138 ierr = MPI_Test(&barrier,&done,MPI_STATUS_IGNORE);CHKERRQ(ierr); 139 } 140 } 141 *nfrom = nrecvs; 142 ierr = PetscSegBufferExtractAlloc(segrank,fromranks);CHKERRQ(ierr); 143 ierr = PetscSegBufferDestroy(&segrank);CHKERRQ(ierr); 144 ierr = PetscSegBufferExtractAlloc(segdata,fromdata);CHKERRQ(ierr); 145 ierr = PetscSegBufferDestroy(&segdata);CHKERRQ(ierr); 146 ierr = PetscCommDestroy(&comm);CHKERRQ(ierr); 147 PetscFunctionReturn(0); 148 } 149 #endif 150 151 #undef __FUNCT__ 152 #define __FUNCT__ "PetscCommBuildTwoSided_Allreduce" 153 static PetscErrorCode PetscCommBuildTwoSided_Allreduce(MPI_Comm comm,PetscMPIInt count,MPI_Datatype dtype,PetscMPIInt nto,const PetscMPIInt *toranks,const void *todata,PetscMPIInt *nfrom,PetscMPIInt **fromranks,void *fromdata) 154 { 155 PetscErrorCode ierr; 156 PetscMPIInt size,*iflags,nrecvs,tag,*franks,i; 157 MPI_Aint lb,unitbytes; 158 char *tdata,*fdata; 159 MPI_Request *reqs,*sendreqs; 160 MPI_Status *statuses; 161 162 PetscFunctionBegin; 163 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 164 ierr = PetscCalloc1(size,&iflags);CHKERRQ(ierr); 165 for (i=0; i<nto; i++) iflags[toranks[i]] = 1; 166 ierr = PetscGatherNumberOfMessages(comm,iflags,NULL,&nrecvs);CHKERRQ(ierr); 167 ierr = PetscFree(iflags);CHKERRQ(ierr); 168 169 ierr = PetscCommDuplicate(comm,&comm,&tag);CHKERRQ(ierr); 170 ierr = MPI_Type_get_extent(dtype,&lb,&unitbytes);CHKERRQ(ierr); 171 if (lb != 0) SETERRQ1(comm,PETSC_ERR_SUP,"Datatype with nonzero lower bound %ld\n",(long)lb); 172 ierr = PetscMalloc(nrecvs*count*unitbytes,&fdata);CHKERRQ(ierr); 173 tdata = (char*)todata; 174 ierr = PetscMalloc2(nto+nrecvs,&reqs,nto+nrecvs,&statuses);CHKERRQ(ierr); 175 sendreqs = reqs + nrecvs; 176 for (i=0; i<nrecvs; i++) { 177 ierr = MPI_Irecv((void*)(fdata+count*unitbytes*i),count,dtype,MPI_ANY_SOURCE,tag,comm,reqs+i);CHKERRQ(ierr); 178 } 179 for (i=0; i<nto; i++) { 180 ierr = MPI_Isend((void*)(tdata+count*unitbytes*i),count,dtype,toranks[i],tag,comm,sendreqs+i);CHKERRQ(ierr); 181 } 182 ierr = MPI_Waitall(nto+nrecvs,reqs,statuses);CHKERRQ(ierr); 183 ierr = PetscMalloc1(nrecvs,&franks);CHKERRQ(ierr); 184 for (i=0; i<nrecvs; i++) franks[i] = statuses[i].MPI_SOURCE; 185 ierr = PetscFree2(reqs,statuses);CHKERRQ(ierr); 186 ierr = PetscCommDestroy(&comm);CHKERRQ(ierr); 187 188 *nfrom = nrecvs; 189 *fromranks = franks; 190 *(void**)fromdata = fdata; 191 PetscFunctionReturn(0); 192 } 193 194 #if defined(PETSC_HAVE_MPI_REDUCE_SCATTER_BLOCK) 195 #undef __FUNCT__ 196 #define __FUNCT__ "PetscCommBuildTwoSided_RedScatter" 197 static PetscErrorCode PetscCommBuildTwoSided_RedScatter(MPI_Comm comm,PetscMPIInt count,MPI_Datatype dtype,PetscMPIInt nto,const PetscMPIInt *toranks,const void *todata,PetscMPIInt *nfrom,PetscMPIInt **fromranks,void *fromdata) 198 { 199 PetscErrorCode ierr; 200 PetscMPIInt size,*iflags,nrecvs,tag,*franks,i; 201 MPI_Aint lb,unitbytes; 202 char *tdata,*fdata; 203 MPI_Request *reqs,*sendreqs; 204 MPI_Status *statuses; 205 206 PetscFunctionBegin; 207 ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr); 208 ierr = PetscMalloc1(size,&iflags);CHKERRQ(ierr); 209 ierr = PetscMemzero(iflags,size*sizeof(*iflags));CHKERRQ(ierr); 210 for (i=0; i<nto; i++) iflags[toranks[i]] = 1; 211 ierr = MPI_Reduce_scatter_block(iflags,&nrecvs,1,MPI_INT,MPI_SUM,comm);CHKERRQ(ierr); 212 ierr = PetscFree(iflags);CHKERRQ(ierr); 213 214 ierr = PetscCommDuplicate(comm,&comm,&tag);CHKERRQ(ierr); 215 ierr = MPI_Type_get_extent(dtype,&lb,&unitbytes);CHKERRQ(ierr); 216 if (lb != 0) SETERRQ1(comm,PETSC_ERR_SUP,"Datatype with nonzero lower bound %ld\n",(long)lb); 217 ierr = PetscMalloc(nrecvs*count*unitbytes,&fdata);CHKERRQ(ierr); 218 tdata = (char*)todata; 219 ierr = PetscMalloc2(nto+nrecvs,&reqs,nto+nrecvs,&statuses);CHKERRQ(ierr); 220 sendreqs = reqs + nrecvs; 221 for (i=0; i<nrecvs; i++) { 222 ierr = MPI_Irecv((void*)(fdata+count*unitbytes*i),count,dtype,MPI_ANY_SOURCE,tag,comm,reqs+i);CHKERRQ(ierr); 223 } 224 for (i=0; i<nto; i++) { 225 ierr = MPI_Isend((void*)(tdata+count*unitbytes*i),count,dtype,toranks[i],tag,comm,sendreqs+i);CHKERRQ(ierr); 226 } 227 ierr = MPI_Waitall(nto+nrecvs,reqs,statuses);CHKERRQ(ierr); 228 ierr = PetscMalloc1(nrecvs,&franks);CHKERRQ(ierr); 229 for (i=0; i<nrecvs; i++) franks[i] = statuses[i].MPI_SOURCE; 230 ierr = PetscFree2(reqs,statuses);CHKERRQ(ierr); 231 ierr = PetscCommDestroy(&comm);CHKERRQ(ierr); 232 233 *nfrom = nrecvs; 234 *fromranks = franks; 235 *(void**)fromdata = fdata; 236 PetscFunctionReturn(0); 237 } 238 #endif 239 240 #undef __FUNCT__ 241 #define __FUNCT__ "PetscCommBuildTwoSided" 242 /*@C 243 PetscCommBuildTwoSided - discovers communicating ranks given one-sided information, moving constant-sized data in the process (often message lengths) 244 245 Collective on MPI_Comm 246 247 Input Arguments: 248 + comm - communicator 249 . count - number of entries to send/receive (must match on all ranks) 250 . dtype - datatype to send/receive from each rank (must match on all ranks) 251 . nto - number of ranks to send data to 252 . toranks - ranks to send to (array of length nto) 253 - todata - data to send to each rank (packed) 254 255 Output Arguments: 256 + nfrom - number of ranks receiving messages from 257 . fromranks - ranks receiving messages from (length nfrom; caller should PetscFree()) 258 - fromdata - packed data from each rank, each with count entries of type dtype (length nfrom, caller responsible for PetscFree()) 259 260 Level: developer 261 262 Options Database Keys: 263 . -build_twosided <allreduce|ibarrier|redscatter> - algorithm to set up two-sided communication 264 265 Notes: 266 This memory-scalable interface is an alternative to calling PetscGatherNumberOfMessages() and 267 PetscGatherMessageLengths(), possibly with a subsequent round of communication to send other constant-size data. 268 269 Basic data types as well as contiguous types are supported, but non-contiguous (e.g., strided) types are not. 270 271 References: 272 The MPI_Ibarrier implementation uses the algorithm in 273 Hoefler, Siebert and Lumsdaine, Scalable communication protocols for dynamic sparse data exchange, 2010. 274 275 .seealso: PetscGatherNumberOfMessages(), PetscGatherMessageLengths() 276 @*/ 277 PetscErrorCode PetscCommBuildTwoSided(MPI_Comm comm,PetscMPIInt count,MPI_Datatype dtype,PetscMPIInt nto,const PetscMPIInt *toranks,const void *todata,PetscMPIInt *nfrom,PetscMPIInt **fromranks,void *fromdata) 278 { 279 PetscErrorCode ierr; 280 PetscBuildTwoSidedType buildtype = PETSC_BUILDTWOSIDED_NOTSET; 281 282 PetscFunctionBegin; 283 ierr = PetscSysInitializePackage();CHKERRQ(ierr); 284 ierr = PetscLogEventBegin(PETSC_BuildTwoSided,0,0,0,0);CHKERRQ(ierr); 285 ierr = PetscCommBuildTwoSidedGetType(comm,&buildtype);CHKERRQ(ierr); 286 switch (buildtype) { 287 case PETSC_BUILDTWOSIDED_IBARRIER: 288 #if defined(PETSC_HAVE_MPI_IBARRIER) 289 ierr = PetscCommBuildTwoSided_Ibarrier(comm,count,dtype,nto,toranks,todata,nfrom,fromranks,fromdata);CHKERRQ(ierr); 290 #else 291 SETERRQ(comm,PETSC_ERR_PLIB,"MPI implementation does not provide MPI_Ibarrier (part of MPI-3)"); 292 #endif 293 break; 294 case PETSC_BUILDTWOSIDED_ALLREDUCE: 295 ierr = PetscCommBuildTwoSided_Allreduce(comm,count,dtype,nto,toranks,todata,nfrom,fromranks,fromdata);CHKERRQ(ierr); 296 break; 297 case PETSC_BUILDTWOSIDED_REDSCATTER: 298 #if defined(PETSC_HAVE_MPI_REDUCE_SCATTER_BLOCK) 299 ierr = PetscCommBuildTwoSided_RedScatter(comm,count,dtype,nto,toranks,todata,nfrom,fromranks,fromdata);CHKERRQ(ierr); 300 #else 301 SETERRQ(comm,PETSC_ERR_PLIB,"MPI implementation does not provide MPI_Reduce_scatter_block (part of MPI-2.2)"); 302 #endif 303 break; 304 default: SETERRQ(comm,PETSC_ERR_PLIB,"Unknown method for building two-sided communication"); 305 } 306 ierr = PetscLogEventEnd(PETSC_BuildTwoSided,0,0,0,0);CHKERRQ(ierr); 307 PetscFunctionReturn(0); 308 } 309