xref: /petsc/src/vec/is/sf/impls/basic/allgather/sfallgather.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1 #include <../src/vec/is/sf/impls/basic/allgatherv/sfallgatherv.h>
2 
3 #define PetscSFPackGet_Allgather PetscSFPackGet_Allgatherv
4 
5 /* Reuse the type. The difference is some fields (i.e., displs, recvcounts) are not used in Allgather on rank != 0, which is not a big deal */
6 typedef PetscSF_Allgatherv PetscSF_Allgather;
7 
8 PETSC_INTERN PetscErrorCode PetscSFBcastAndOpBegin_Gather(PetscSF,MPI_Datatype,PetscMemType,const void*,PetscMemType,void*,MPI_Op);
9 
10 static PetscErrorCode PetscSFBcastAndOpBegin_Allgather(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
11 {
12   PetscErrorCode        ierr;
13   PetscSFPack           link;
14   PetscMPIInt           sendcount;
15   MPI_Comm              comm;
16   const void            *rootbuf_mpi; /* buffer used by MPI */
17   void                  *leafbuf_mpi;
18   PetscMemType          rootmtype_mpi,leafmtype_mpi;
19 
20   PetscFunctionBegin;
21   ierr = PetscSFPackGet_Allgather(sf,unit,rootmtype,rootdata,leafmtype,leafdata,&link);CHKERRQ(ierr);
22   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
23   ierr = PetscMPIIntCast(sf->nroots,&sendcount);CHKERRQ(ierr);
24   ierr = PetscSFBcastPrepareMPIBuffers_Allgatherv(sf,link,op,&rootmtype_mpi,&rootbuf_mpi,&leafmtype_mpi,&leafbuf_mpi);CHKERRQ(ierr);
25   ierr = MPIU_Iallgather(rootbuf_mpi,sendcount,unit,leafbuf_mpi,sendcount,unit,comm,link->rootreqs[PETSCSF_ROOT2LEAF_BCAST][rootmtype_mpi]);CHKERRQ(ierr);
26   PetscFunctionReturn(0);
27 }
28 
29 static PetscErrorCode PetscSFReduceBegin_Allgather(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
30 {
31   PetscErrorCode        ierr;
32   PetscSFPack           link;
33   PetscMPIInt           sendcount;
34   PetscInt              rstart;
35   MPI_Comm              comm;
36   const void            *leafbuf_mpi;
37   void                  *rootbuf_mpi;
38   PetscMemType          leafmtype_mpi,rootmtype_mpi;
39 
40   PetscFunctionBegin;
41   ierr = PetscSFPackGet_Allgather(sf,unit,rootmtype,rootdata,leafmtype,leafdata,&link);CHKERRQ(ierr);
42   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
43 
44   if (op == MPIU_REPLACE) {
45     /* REPLACE is only meaningful when all processes have the same leafdata to reduce. Therefore copy from local leafdata is fine */
46     ierr = PetscLayoutGetRange(sf->map,&rstart,NULL);CHKERRQ(ierr);
47     ierr = PetscMemcpyWithMemType(rootmtype,leafmtype,rootdata,(const char*)leafdata+(size_t)rstart*link->unitbytes,(size_t)sf->nroots*link->unitbytes);CHKERRQ(ierr);
48   } else {
49     ierr = PetscMPIIntCast(sf->nroots,&sendcount);CHKERRQ(ierr);
50     ierr = PetscSFReducePrepareMPIBuffers_Allgatherv(sf,link,op,&rootmtype_mpi,&rootbuf_mpi,&leafmtype_mpi,&leafbuf_mpi);CHKERRQ(ierr);
51     ierr = MPIU_Iscatter(leafbuf_mpi,sendcount,unit,rootbuf_mpi,sendcount,unit,0/*rank 0*/,comm,link->rootreqs[PETSCSF_LEAF2ROOT_REDUCE][rootmtype_mpi]);CHKERRQ(ierr);
52   }
53   PetscFunctionReturn(0);
54 }
55 
56 static PetscErrorCode PetscSFBcastToZero_Allgather(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata)
57 {
58   PetscErrorCode        ierr;
59   PetscSFPack           link;
60   PetscMPIInt           rank;
61 
62   PetscFunctionBegin;
63   ierr = PetscSFBcastAndOpBegin_Gather(sf,unit,rootmtype,rootdata,leafmtype,leafdata,MPIU_REPLACE);CHKERRQ(ierr);
64   ierr = PetscSFPackGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);CHKERRQ(ierr);
65   ierr = PetscSFPackWaitall(link,PETSCSF_ROOT2LEAF_BCAST);CHKERRQ(ierr);
66   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)sf),&rank);CHKERRQ(ierr);
67   if (!rank && leafmtype == PETSC_MEMTYPE_DEVICE && !use_gpu_aware_mpi) {
68     ierr = PetscMemcpyWithMemType(PETSC_MEMTYPE_DEVICE,PETSC_MEMTYPE_HOST,leafdata,link->leafbuf[PETSC_MEMTYPE_HOST],link->leafbuflen*link->unitbytes);CHKERRQ(ierr);
69   }
70   ierr = PetscSFPackReclaim(sf,&link);CHKERRQ(ierr);
71   PetscFunctionReturn(0);
72 }
73 
74 PETSC_INTERN PetscErrorCode PetscSFCreate_Allgather(PetscSF sf)
75 {
76   PetscErrorCode    ierr;
77   PetscSF_Allgather *dat = (PetscSF_Allgather*)sf->data;
78 
79   PetscFunctionBegin;
80 
81   /* Inherit from Allgatherv */
82   sf->ops->Reset           = PetscSFReset_Allgatherv;
83   sf->ops->Destroy         = PetscSFDestroy_Allgatherv;
84   sf->ops->BcastAndOpEnd   = PetscSFBcastAndOpEnd_Allgatherv;
85   sf->ops->ReduceEnd       = PetscSFReduceEnd_Allgatherv;
86   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Allgatherv;
87   sf->ops->FetchAndOpEnd   = PetscSFFetchAndOpEnd_Allgatherv;
88   sf->ops->GetRootRanks    = PetscSFGetRootRanks_Allgatherv;
89   sf->ops->CreateLocalSF   = PetscSFCreateLocalSF_Allgatherv;
90   sf->ops->GetGraph        = PetscSFGetGraph_Allgatherv;
91   sf->ops->GetLeafRanks    = PetscSFGetLeafRanks_Allgatherv;
92 
93   /* Allgather stuff */
94   sf->ops->BcastAndOpBegin = PetscSFBcastAndOpBegin_Allgather;
95   sf->ops->ReduceBegin     = PetscSFReduceBegin_Allgather;
96   sf->ops->BcastToZero     = PetscSFBcastToZero_Allgather;
97 
98   ierr = PetscNewLog(sf,&dat);CHKERRQ(ierr);
99   sf->data = (void*)dat;
100   PetscFunctionReturn(0);
101 }
102