xref: /petsc/src/vec/is/sf/impls/basic/neighbor/sfneighbor.c (revision da2e4c716b07eca3d96b2ac4bb4329ffd7cd520e)
1 #include <../src/vec/is/sf/impls/basic/sfpack.h>
2 #include <../src/vec/is/sf/impls/basic/sfbasic.h>
3 
4 #if defined(PETSC_HAVE_MPI_NEIGHBORHOOD_COLLECTIVES)
5 
6 /* SF Neighbor completely relies on the two sided info built by SF Basic. Therefore we build Neighbor as a subclass of Basic */
7 
8 typedef struct {
9   SPPACKBASICHEADER;
10   char *rootbuf; /* contiguous buffer for all root ranks */
11   char *leafbuf; /* contiguous buffer for all non-distinguished leaf ranks. Distiguished ones share root buffers. */
12 } *PetscSFPack_Neighbor;
13 
14 typedef struct {
15   SFBASICHEADER;
16   MPI_Comm      comms[2];       /* Communicators with distributed topology in both directions */
17   PetscBool     initialized[2]; /* Are the two communicators initialized? */
18   PetscMPIInt   *rootdispls,*rootcounts,*leafdispls,*leafcounts; /* displs/counts for non-distinguished ranks */
19 } PetscSF_Neighbor;
20 
21 /*===================================================================================*/
22 /*              Internal utility routines                                            */
23 /*===================================================================================*/
24 
25 /* Get the communicator with distributed graph topology, which is not cheap to build so we do it on demand (instead of at PetscSFSetUp time) */
26 static PetscErrorCode PetscSFGetDistComm_Neighbor(PetscSF sf,PetscSFDirection direction,MPI_Comm *distcomm)
27 {
28   PetscErrorCode    ierr;
29   PetscSF_Neighbor  *dat = (PetscSF_Neighbor*)sf->data;
30   PetscInt          nrootranks,ndrootranks,nleafranks,ndleafranks;
31   const PetscMPIInt *rootranks,*leafranks;
32   MPI_Comm          comm;
33 
34   PetscFunctionBegin;
35   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,&rootranks,NULL,NULL);CHKERRQ(ierr);      /* Which ranks will access my roots (I am a destination) */
36   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,&leafranks,NULL,NULL,NULL);CHKERRQ(ierr); /* My leaves will access whose roots (I am a source) */
37 
38   if (!dat->initialized[direction]) {
39     const PetscMPIInt indegree  = nrootranks-ndrootranks,*sources      = rootranks+ndrootranks;
40     const PetscMPIInt outdegree = nleafranks-ndleafranks,*destinations = leafranks+ndleafranks;
41     MPI_Comm          *mycomm   = &dat->comms[direction];
42     ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
43     if (direction == PETSCSF_LEAF2ROOT_REDUCE) {
44       ierr = MPI_Dist_graph_create_adjacent(comm,indegree,sources,dat->rootcounts/*src weights*/,outdegree,destinations,dat->leafcounts/*dest weights*/,MPI_INFO_NULL,1/*reorder*/,mycomm);CHKERRQ(ierr);
45     } else { /* PETSCSF_ROOT2LEAF_BCAST, reverse src & dest */
46       ierr = MPI_Dist_graph_create_adjacent(comm,outdegree,destinations,dat->leafcounts/*src weights*/,indegree,sources,dat->rootcounts/*dest weights*/,MPI_INFO_NULL,1/*reorder*/,mycomm);CHKERRQ(ierr);
47     }
48     dat->initialized[direction] = PETSC_TRUE;
49   }
50   *distcomm = dat->comms[direction];
51   PetscFunctionReturn(0);
52 }
53 
54 static PetscErrorCode PetscSFPackGet_Neighbor(PetscSF sf,MPI_Datatype unit,const void *key,PetscSFDirection direction,PetscSFPack_Neighbor *mylink)
55 {
56   PetscErrorCode       ierr;
57   PetscSF_Neighbor     *dat = (PetscSF_Neighbor*)sf->data;
58   PetscInt             i,nrootranks,ndrootranks,nleafranks,ndleafranks;
59   const PetscInt       *rootoffset,*leafoffset;
60   PetscSFPack          *p;
61   PetscSFPack_Neighbor link;
62 
63   PetscFunctionBegin;
64   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,NULL,&rootoffset,NULL);CHKERRQ(ierr);
65   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,NULL,&leafoffset,NULL,NULL);CHKERRQ(ierr);
66 
67   /* Look for types in cache */
68   for (p=&dat->avail; (link=(PetscSFPack_Neighbor)*p); p=&link->next) {
69     PetscBool match;
70     ierr = MPIPetsc_Type_compare(unit,link->unit,&match);CHKERRQ(ierr);
71     if (match) {
72       *p = link->next; /* Remove from available list */
73       goto found;
74     }
75   }
76 
77   ierr = PetscNew(&link);CHKERRQ(ierr);
78   ierr = PetscSFPackSetupType((PetscSFPack)link,unit);CHKERRQ(ierr);
79   ierr = PetscMalloc2(nrootranks,&link->root,nleafranks,&link->leaf);CHKERRQ(ierr);
80   /* Double the requests. First half are used for reduce (leaf2root) communication, second half for bcast (root2leaf) communication */
81   link->half = 1;
82   ierr       = PetscMalloc1(link->half*2,&link->requests);CHKERRQ(ierr);
83   ierr       = PetscCommGetNewTag(PetscObjectComm((PetscObject)sf),&link->tag);CHKERRQ(ierr); /* Actually, tag is not need for neighborhood collectives */
84 
85   /* Allocate root and leaf buffers */
86   ierr = PetscMalloc2(rootoffset[nrootranks]*link->unitbytes,&link->rootbuf,(leafoffset[nleafranks]-leafoffset[ndleafranks])*link->unitbytes,&link->leafbuf);CHKERRQ(ierr);
87   for (i=0; i<nrootranks; i++) link->root[i] = link->rootbuf + rootoffset[i]*link->unitbytes;
88   for (i=0; i<nleafranks; i++) {
89     if (i < ndleafranks) { /* Leaf buffers for distinguished ranks are pointers directly into root buffers */
90       if (ndrootranks != 1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot match distinguished ranks");
91       link->leaf[i] = link->root[0];
92       continue;
93     }
94     link->leaf[i] = link->leafbuf + (leafoffset[i] - leafoffset[ndleafranks])*link->unitbytes;
95   }
96 
97 found:
98   link->key  = key;
99   link->next = dat->inuse;
100   dat->inuse = (PetscSFPack)link;
101   *mylink    = link;
102   PetscFunctionReturn(0);
103 }
104 
105 /*===================================================================================*/
106 /*              Implementations of SF public APIs                                    */
107 /*===================================================================================*/
108 static PetscErrorCode PetscSFSetUp_Neighbor(PetscSF sf)
109 {
110   PetscErrorCode   ierr;
111   PetscSF_Neighbor *dat = (PetscSF_Neighbor*)sf->data;
112   PetscInt         i,j,nrootranks,ndrootranks,nleafranks,ndleafranks;
113   const PetscInt   *rootoffset,*leafoffset;
114   PetscMPIInt      m,n;
115 
116   PetscFunctionBegin;
117   ierr = PetscSFSetUp_Basic(sf);CHKERRQ(ierr);
118   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,NULL,&rootoffset,NULL);CHKERRQ(ierr);
119   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,NULL,&leafoffset,NULL,NULL);CHKERRQ(ierr);
120 
121   /* Only setup MPI displs/counts for non-distinguished ranks. Distinguished ranks use shared memory */
122   ierr = PetscMalloc4(nrootranks-ndrootranks,&dat->rootdispls,nrootranks-ndrootranks,&dat->rootcounts,nleafranks-ndleafranks,&dat->leafdispls,nleafranks-ndleafranks,&dat->leafcounts);CHKERRQ(ierr);
123   for (i=ndrootranks,j=0; i<nrootranks; i++,j++) {
124     ierr = PetscMPIIntCast(rootoffset[i]-rootoffset[ndrootranks],&m);CHKERRQ(ierr); dat->rootdispls[j] = m;
125     ierr = PetscMPIIntCast(rootoffset[i+1]-rootoffset[i],        &n);CHKERRQ(ierr); dat->rootcounts[j] = n;
126   }
127 
128   for (i=ndleafranks,j=0; i<nleafranks; i++,j++) {
129     ierr = PetscMPIIntCast(leafoffset[i]-leafoffset[ndleafranks],&m);CHKERRQ(ierr); dat->leafdispls[j] = m;
130     ierr = PetscMPIIntCast(leafoffset[i+1]-leafoffset[i],        &n);CHKERRQ(ierr); dat->leafcounts[j] = n;
131   }
132   PetscFunctionReturn(0);
133 }
134 
135 static PetscErrorCode PetscSFReset_Neighbor(PetscSF sf)
136 {
137   PetscErrorCode       ierr;
138   PetscInt             i;
139   PetscSF_Neighbor     *dat = (PetscSF_Neighbor*)sf->data;
140   PetscSFPack_Neighbor link,next;
141 
142   PetscFunctionBegin;
143   if (dat->inuse) SETERRQ(PetscObjectComm((PetscObject)sf),PETSC_ERR_ARG_WRONGSTATE,"Outstanding operation has not been completed");
144   ierr = PetscFree4(dat->rootdispls,dat->rootcounts,dat->leafdispls,dat->leafcounts);CHKERRQ(ierr);
145   for (i=0; i<2; i++) {
146     if (dat->initialized[i]) {
147       ierr = MPI_Comm_free(&dat->comms[i]);CHKERRQ(ierr);
148       dat->initialized[i] = PETSC_FALSE;
149     }
150   }
151 
152   ierr = PetscFree2(dat->iranks,dat->ioffset);CHKERRQ(ierr);
153   ierr = PetscFree(dat->irootloc);CHKERRQ(ierr);
154   for (link=(PetscSFPack_Neighbor)dat->avail; link; link=next) {
155     next = (PetscSFPack_Neighbor)link->next;
156     if (!link->isbuiltin) {ierr = MPI_Type_free(&link->unit);CHKERRQ(ierr);}
157     ierr = PetscFree2(link->root,link->leaf);CHKERRQ(ierr);
158     ierr = PetscFree2(link->rootbuf,link->leafbuf);CHKERRQ(ierr);
159     ierr = PetscFree(link->requests);CHKERRQ(ierr);
160     ierr = PetscFree(link);CHKERRQ(ierr);
161   }
162   dat->avail = NULL;
163   ierr = PetscSFPackDestoryOptimization(&sf->leafpackopt);CHKERRQ(ierr);
164   ierr = PetscSFPackDestoryOptimization(&dat->rootpackopt);CHKERRQ(ierr);
165   PetscFunctionReturn(0);
166 }
167 
168 static PetscErrorCode PetscSFDestroy_Neighbor(PetscSF sf)
169 {
170   PetscErrorCode ierr;
171 
172   PetscFunctionBegin;
173   ierr = PetscSFReset_Neighbor(sf);CHKERRQ(ierr);
174   ierr = PetscFree(sf->data);CHKERRQ(ierr);
175   PetscFunctionReturn(0);
176 }
177 
178 static PetscErrorCode PetscSFBcastAndOpBegin_Neighbor(PetscSF sf,MPI_Datatype unit,const void *rootdata,void *leafdata,MPI_Op op)
179 {
180   PetscErrorCode       ierr;
181   PetscSFPack_Neighbor link;
182   PetscInt             i,nrootranks,ndrootranks,nleafranks,ndleafranks;
183   const PetscInt       *rootoffset,*rootloc;
184   PetscMPIInt          n,ind,outd;
185   PetscSF_Neighbor     *dat = (PetscSF_Neighbor*)sf->data;
186   MPI_Comm             distcomm;
187   MPI_Request          *req;
188   void                 *sbuf,*rbuf;
189 
190   PetscFunctionBegin;
191   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,NULL,&rootoffset,&rootloc);CHKERRQ(ierr);
192   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
193   ierr = PetscSFPackGet_Neighbor(sf,unit,rootdata,PETSCSF_ROOT2LEAF_BCAST,&link);CHKERRQ(ierr);
194 
195   /* Pack root data */
196   for (i=0; i<nrootranks; i++) {
197     void *packstart = link->root[i];
198     ierr = PetscMPIIntCast(rootoffset[i+1]-rootoffset[i],&n);CHKERRQ(ierr);
199     (*link->Pack)(n,link->bs,rootloc+rootoffset[i],i,dat->rootpackopt,rootdata,packstart);
200   }
201 
202   /* Do neighborhood alltoallv for non-distinguished ranks */
203   req  = &link->requests[PETSCSF_ROOT2LEAF_BCAST];
204   ierr = PetscSFGetDistComm_Neighbor(sf,PETSCSF_ROOT2LEAF_BCAST,&distcomm);CHKERRQ(ierr);
205   outd = nrootranks - ndrootranks;
206   ind  = nleafranks - ndleafranks;
207   sbuf = link->root ? link->root[ndrootranks] : NULL;
208   rbuf = link->leaf ? link->leaf[ndleafranks] : NULL;
209   ierr = MPI_Start_ineighbor_alltoallv(outd,ind,sbuf,dat->rootcounts,dat->rootdispls,unit,rbuf,dat->leafcounts,dat->leafdispls,unit,distcomm,req);CHKERRQ(ierr);
210   PetscFunctionReturn(0);
211 }
212 
213 static PetscErrorCode PetscSFReduceBegin_Neighbor(PetscSF sf,MPI_Datatype unit,const void *leafdata,void *rootdata,MPI_Op op)
214 {
215   PetscErrorCode       ierr;
216   PetscInt             i,nrootranks,ndrootranks,nleafranks,ndleafranks;
217   const PetscInt       *leafoffset,*leafloc;
218   PetscMPIInt          n,ind,outd;
219   PetscSFPack_Neighbor link;
220   PetscSF_Neighbor     *dat = (PetscSF_Neighbor*)sf->data;
221   MPI_Comm             distcomm;
222   MPI_Request          *req;
223   void                 *sbuf,*rbuf;
224 
225   PetscFunctionBegin;
226   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,NULL,NULL,NULL);CHKERRQ(ierr);
227   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,NULL,&leafoffset,&leafloc,NULL);CHKERRQ(ierr);
228   ierr = PetscSFPackGet_Neighbor(sf,unit,leafdata,PETSCSF_LEAF2ROOT_REDUCE,&link);CHKERRQ(ierr);
229 
230   /* Pack leaf data */
231   for (i=0; i<nleafranks; i++) {
232     void *packstart = link->leaf[i];
233     ierr = PetscMPIIntCast(leafoffset[i+1]-leafoffset[i],&n);CHKERRQ(ierr);
234     (*link->Pack)(n,link->bs,leafloc+leafoffset[i],i,sf->leafpackopt,leafdata,packstart);
235   }
236 
237   /* Do neighborhood alltoallv for non-distinguished ranks */
238   req  = &link->requests[PETSCSF_LEAF2ROOT_REDUCE];
239   ierr = PetscSFGetDistComm_Neighbor(sf,PETSCSF_LEAF2ROOT_REDUCE,&distcomm);CHKERRQ(ierr);
240   ind  = nrootranks - ndrootranks;
241   outd = nleafranks - ndleafranks;
242   sbuf = link->leaf ? link->leaf[ndleafranks] : NULL;
243   rbuf = link->root ? link->root[ndrootranks] : NULL;
244   ierr = MPI_Start_ineighbor_alltoallv(outd,ind,sbuf,dat->leafcounts,dat->leafdispls,unit,rbuf,dat->rootcounts,dat->rootdispls,unit,distcomm,req);CHKERRQ(ierr);
245   PetscFunctionReturn(0);
246 }
247 
248 static PetscErrorCode PetscSFFetchAndOpEnd_Neighbor(PetscSF sf,MPI_Datatype unit,void *rootdata,const void *leafdata,void *leafupdate,MPI_Op op)
249 {
250   PetscErrorCode    ierr;
251   PetscErrorCode    (*FetchAndOp)(PetscInt,PetscInt,const PetscInt*,PetscInt,PetscSFPackOpt,void*,void*);
252   PetscSFPack_Basic link;
253   PetscInt          i,nrootranks,ndrootranks,nleafranks,ndleafranks;
254   const PetscInt    *rootoffset,*leafoffset,*rootloc,*leafloc;
255   const PetscMPIInt *rootranks,*leafranks;
256   MPI_Comm          comm;
257   PetscMPIInt       n,ind,outd;
258   PetscSF_Neighbor  *dat = (PetscSF_Neighbor*)sf->data;
259   void              *sbuf,*rbuf;
260 
261   PetscFunctionBegin;
262   ierr = PetscSFPackGetInUse(sf,unit,leafdata,PETSC_OWN_POINTER,(PetscSFPack*)&link);CHKERRQ(ierr);
263   ierr = PetscSFPackWaitall_Basic(link,PETSCSF_LEAF2ROOT_REDUCE);CHKERRQ(ierr);
264 
265   ierr = PetscSFGetRootInfo_Basic(sf,&nrootranks,&ndrootranks,&rootranks,&rootoffset,&rootloc);CHKERRQ(ierr);
266   ierr = PetscSFGetLeafInfo_Basic(sf,&nleafranks,&ndleafranks,&leafranks,&leafoffset,&leafloc,NULL);CHKERRQ(ierr);
267 
268   /* Process local fetch-and-op */
269   ierr = PetscSFPackGetFetchAndOp(sf,(PetscSFPack)link,op,&FetchAndOp);CHKERRQ(ierr);
270   for (i=0; i<nrootranks; i++) {
271     void *packstart = link->root[i];
272     ierr = PetscMPIIntCast(rootoffset[i+1]-rootoffset[i],&n);CHKERRQ(ierr);
273     (*FetchAndOp)(n,link->bs,rootloc+rootoffset[i],i,dat->rootpackopt,rootdata,packstart);
274   }
275 
276   /* Bcast the updated root buffer back to leaves */
277   ierr = PetscSFGetDistComm_Neighbor(sf,PETSCSF_ROOT2LEAF_BCAST,&comm);CHKERRQ(ierr);
278   outd = nrootranks - ndrootranks;
279   ind  = nleafranks - ndleafranks;
280   sbuf = link->root ? link->root[ndrootranks] : NULL;
281   rbuf = link->leaf ? link->leaf[ndleafranks] : NULL;
282   ierr = MPI_Start_neighbor_alltoallv(outd,ind,sbuf,dat->rootcounts,dat->rootdispls,unit,rbuf,dat->leafcounts,dat->leafdispls,unit,comm);CHKERRQ(ierr);
283 
284   for (i=0; i<nleafranks; i++) {
285     const void *packstart = link->leaf[i];
286     ierr = PetscMPIIntCast(leafoffset[i+1]-leafoffset[i],&n);CHKERRQ(ierr);
287     (*link->UnpackAndInsert)(n,link->bs,leafloc+leafoffset[i],i,sf->leafpackopt,leafupdate,packstart);
288   }
289 
290   ierr = PetscSFPackReclaim(sf,(PetscSFPack*)&link);CHKERRQ(ierr);
291   PetscFunctionReturn(0);
292 }
293 
294 PETSC_INTERN PetscErrorCode PetscSFCreate_Neighbor(PetscSF sf)
295 {
296   PetscErrorCode   ierr;
297   PetscSF_Neighbor *dat;
298 
299   PetscFunctionBegin;
300   sf->ops->CreateEmbeddedSF     = PetscSFCreateEmbeddedSF_Basic;
301   sf->ops->CreateEmbeddedLeafSF = PetscSFCreateEmbeddedLeafSF_Basic;
302   sf->ops->BcastAndOpEnd        = PetscSFBcastAndOpEnd_Basic;
303   sf->ops->ReduceEnd            = PetscSFReduceEnd_Basic;
304   sf->ops->FetchAndOpBegin      = PetscSFFetchAndOpBegin_Basic;
305   sf->ops->GetLeafRanks         = PetscSFGetLeafRanks_Basic;
306   sf->ops->View                 = PetscSFView_Basic;
307 
308   sf->ops->SetUp                = PetscSFSetUp_Neighbor;
309   sf->ops->Reset                = PetscSFReset_Neighbor;
310   sf->ops->Destroy              = PetscSFDestroy_Neighbor;
311   sf->ops->BcastAndOpBegin      = PetscSFBcastAndOpBegin_Neighbor;
312   sf->ops->ReduceBegin          = PetscSFReduceBegin_Neighbor;
313   sf->ops->FetchAndOpEnd        = PetscSFFetchAndOpEnd_Neighbor;
314 
315   ierr = PetscNewLog(sf,&dat);CHKERRQ(ierr);
316   sf->data = (void*)dat;
317   PetscFunctionReturn(0);
318 }
319 #endif
320