Actual source code: sfmpi.c
1: /* Mainly for MPI_Isend in SFBASIC. Once SFNEIGHBOR, SFALLGHATERV etc have a persistent version,
2: we can also do abstractions like Prepare/StartCommunication.
3: */
5: #include <../src/vec/is/sf/impls/basic/sfpack.h>
7: /* Start MPI requests. If use non-GPU aware MPI, we might need to copy data from device buf to host buf */
8: static PetscErrorCode PetscSFLinkStartRequests_MPI(PetscSF sf, PetscSFLink link, PetscSFDirection direction)
9: {
10: PetscMPIInt nreqs;
11: MPI_Request *reqs = NULL;
12: PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
13: PetscInt buflen;
15: buflen = (direction == PETSCSF_../../../../../..2LEAF) ? sf->leafbuflen[PETSCSF_REMOTE] : bas->rootbuflen[PETSCSF_REMOTE];
16: if (buflen) {
17: if (direction == PETSCSF_../../../../../..2LEAF) {
18: nreqs = sf->nleafreqs;
19: PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, NULL, &reqs);
20: } else { /* leaf to root */
21: nreqs = bas->nrootreqs;
22: PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, &reqs, NULL);
23: }
24: MPI_Startall_irecv(buflen, link->unit, nreqs, reqs);
25: }
27: buflen = (direction == PETSCSF_../../../../../..2LEAF) ? bas->rootbuflen[PETSCSF_REMOTE] : sf->leafbuflen[PETSCSF_REMOTE];
28: if (buflen) {
29: if (direction == PETSCSF_../../../../../..2LEAF) {
30: nreqs = bas->nrootreqs;
31: PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE /*device2host before sending */);
32: PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, &reqs, NULL);
33: } else { /* leaf to root */
34: nreqs = sf->nleafreqs;
35: PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE);
36: PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, NULL, &reqs);
37: }
38: PetscSFLinkSyncStreamBeforeCallMPI(sf, link, direction);
39: MPI_Startall_isend(buflen, link->unit, nreqs, reqs);
40: }
41: return 0;
42: }
44: static PetscErrorCode PetscSFLinkWaitRequests_MPI(PetscSF sf, PetscSFLink link, PetscSFDirection direction)
45: {
46: PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
47: const PetscMemType rootmtype_mpi = link->rootmtype_mpi, leafmtype_mpi = link->leafmtype_mpi;
48: const PetscInt rootdirect_mpi = link->rootdirect_mpi, leafdirect_mpi = link->leafdirect_mpi;
50: MPI_Waitall(bas->nrootreqs, link->rootreqs[direction][rootmtype_mpi][rootdirect_mpi], MPI_STATUSES_IGNORE);
51: MPI_Waitall(sf->nleafreqs, link->leafreqs[direction][leafmtype_mpi][leafdirect_mpi], MPI_STATUSES_IGNORE);
52: if (direction == PETSCSF_../../../../../..2LEAF) {
53: PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_FALSE /* host2device after recving */);
54: } else {
55: PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_FALSE);
56: }
57: return 0;
58: }
60: /*
61: The routine Creates a communication link for the given operation. It first looks up its link cache. If
62: there is a free & suitable one, it uses it. Otherwise it creates a new one.
64: A link contains buffers and MPI requests for send/recv. It also contains pack/unpack routines to pack/unpack
65: root/leafdata to/from these buffers. Buffers are allocated at our discretion. When we find root/leafata
66: can be directly passed to MPI, we won't allocate them. Even we allocate buffers, we only allocate
67: those that are needed by the given `sfop` and `op`, in other words, we do lazy memory-allocation.
69: The routine also allocates buffers on CPU when one does not use gpu-aware MPI but data is on GPU.
71: In SFBasic, MPI requests are persistent. They are init'ed until we try to get requests from a link.
73: The routine is shared by SFBasic and SFNeighbor based on the fact they all deal with sparse graphs and
74: need pack/unpack data.
75: */
76: PetscErrorCode PetscSFLinkCreate_MPI(PetscSF sf, MPI_Datatype unit, PetscMemType xrootmtype, const void *rootdata, PetscMemType xleafmtype, const void *leafdata, MPI_Op op, PetscSFOperation sfop, PetscSFLink *mylink)
77: {
78: PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
79: PetscInt i, j, k, nrootreqs, nleafreqs, nreqs;
80: PetscSFLink *p, link;
81: PetscSFDirection direction;
82: MPI_Request *reqs = NULL;
83: PetscBool match, rootdirect[2], leafdirect[2];
84: PetscMemType rootmtype = PetscMemTypeHost(xrootmtype) ? PETSC_MEMTYPE_HOST : PETSC_MEMTYPE_DEVICE; /* Convert to 0/1 as we will use it in subscript */
85: PetscMemType leafmtype = PetscMemTypeHost(xleafmtype) ? PETSC_MEMTYPE_HOST : PETSC_MEMTYPE_DEVICE;
86: PetscMemType rootmtype_mpi, leafmtype_mpi; /* mtypes seen by MPI */
87: PetscInt rootdirect_mpi, leafdirect_mpi; /* root/leafdirect seen by MPI*/
90: /* Can we directly use root/leafdirect with the given sf, sfop and op? */
91: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
92: if (sfop == PETSCSF_BCAST) {
93: rootdirect[i] = bas->rootcontig[i]; /* Pack roots */
94: leafdirect[i] = (sf->leafcontig[i] && op == MPI_REPLACE) ? PETSC_TRUE : PETSC_FALSE; /* Unpack leaves */
95: } else if (sfop == PETSCSF_REDUCE) {
96: leafdirect[i] = sf->leafcontig[i]; /* Pack leaves */
97: rootdirect[i] = (bas->rootcontig[i] && op == MPI_REPLACE) ? PETSC_TRUE : PETSC_FALSE; /* Unpack roots */
98: } else { /* PETSCSF_FETCH */
99: rootdirect[i] = PETSC_FALSE; /* FETCH always need a separate rootbuf */
100: leafdirect[i] = PETSC_FALSE; /* We also force allocating a separate leafbuf so that leafdata and leafupdate can share mpi requests */
101: }
102: }
104: if (sf->use_gpu_aware_mpi) {
105: rootmtype_mpi = rootmtype;
106: leafmtype_mpi = leafmtype;
107: } else {
108: rootmtype_mpi = leafmtype_mpi = PETSC_MEMTYPE_HOST;
109: }
110: /* Will root/leafdata be directly accessed by MPI? Without use_gpu_aware_mpi, device data is buffered on host and then passed to MPI */
111: rootdirect_mpi = rootdirect[PETSCSF_REMOTE] && (rootmtype_mpi == rootmtype) ? 1 : 0;
112: leafdirect_mpi = leafdirect[PETSCSF_REMOTE] && (leafmtype_mpi == leafmtype) ? 1 : 0;
114: direction = (sfop == PETSCSF_BCAST) ? PETSCSF_../../../../../..2LEAF : PETSCSF_LEAF2../../../../../..;
115: nrootreqs = bas->nrootreqs;
116: nleafreqs = sf->nleafreqs;
118: /* Look for free links in cache */
119: for (p = &bas->avail; (link = *p); p = &link->next) {
120: if (!link->use_nvshmem) { /* Only check with MPI links */
121: MPIPetsc_Type_compare(unit, link->unit, &match);
122: if (match) {
123: /* If root/leafdata will be directly passed to MPI, test if the data used to initialized the MPI requests matches with the current.
124: If not, free old requests. New requests will be lazily init'ed until one calls PetscSFLinkGetMPIBuffersAndRequests().
125: */
126: if (rootdirect_mpi && sf->persistent && link->rootreqsinited[direction][rootmtype][1] && link->rootdatadirect[direction][rootmtype] != rootdata) {
127: reqs = link->rootreqs[direction][rootmtype][1]; /* Here, rootmtype = rootmtype_mpi */
128: for (i = 0; i < nrootreqs; i++) {
129: if (reqs[i] != MPI_REQUEST_NULL) MPI_Request_free(&reqs[i]);
130: }
131: link->rootreqsinited[direction][rootmtype][1] = PETSC_FALSE;
132: }
133: if (leafdirect_mpi && sf->persistent && link->leafreqsinited[direction][leafmtype][1] && link->leafdatadirect[direction][leafmtype] != leafdata) {
134: reqs = link->leafreqs[direction][leafmtype][1];
135: for (i = 0; i < nleafreqs; i++) {
136: if (reqs[i] != MPI_REQUEST_NULL) MPI_Request_free(&reqs[i]);
137: }
138: link->leafreqsinited[direction][leafmtype][1] = PETSC_FALSE;
139: }
140: *p = link->next; /* Remove from available list */
141: goto found;
142: }
143: }
144: }
146: PetscNew(&link);
147: PetscSFLinkSetUp_Host(sf, link, unit);
148: PetscCommGetNewTag(PetscObjectComm((PetscObject)sf), &link->tag); /* One tag per link */
150: nreqs = (nrootreqs + nleafreqs) * 8;
151: PetscMalloc1(nreqs, &link->reqs);
152: for (i = 0; i < nreqs; i++) link->reqs[i] = MPI_REQUEST_NULL; /* Initialized to NULL so that we know which need to be freed in Destroy */
154: for (i = 0; i < 2; i++) { /* Two communication directions */
155: for (j = 0; j < 2; j++) { /* Two memory types */
156: for (k = 0; k < 2; k++) { /* root/leafdirect 0 or 1 */
157: link->rootreqs[i][j][k] = link->reqs + nrootreqs * (4 * i + 2 * j + k);
158: link->leafreqs[i][j][k] = link->reqs + nrootreqs * 8 + nleafreqs * (4 * i + 2 * j + k);
159: }
160: }
161: }
162: link->StartCommunication = PetscSFLinkStartRequests_MPI;
163: link->FinishCommunication = PetscSFLinkWaitRequests_MPI;
165: found:
167: #if defined(PETSC_HAVE_DEVICE)
168: if ((PetscMemTypeDevice(xrootmtype) || PetscMemTypeDevice(xleafmtype)) && !link->deviceinited) {
169: #if defined(PETSC_HAVE_CUDA)
170: if (sf->backend == PETSCSF_BACKEND_CUDA) PetscSFLinkSetUp_CUDA(sf, link, unit); /* Setup streams etc */
171: #endif
172: #if defined(PETSC_HAVE_HIP)
173: if (sf->backend == PETSCSF_BACKEND_HIP) PetscSFLinkSetUp_HIP(sf, link, unit); /* Setup streams etc */
174: #endif
175: #if defined(PETSC_HAVE_KOKKOS)
176: if (sf->backend == PETSCSF_BACKEND_KOKKOS) PetscSFLinkSetUp_Kokkos(sf, link, unit);
177: #endif
178: }
179: #endif
181: /* Allocate buffers along root/leafdata */
182: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
183: /* For local communication, buffers are only needed when roots and leaves have different mtypes */
184: if (i == PETSCSF_LOCAL && rootmtype == leafmtype) continue;
185: if (bas->rootbuflen[i]) {
186: if (rootdirect[i]) { /* Aha, we disguise rootdata as rootbuf */
187: link->rootbuf[i][rootmtype] = (char *)rootdata + bas->rootstart[i] * link->unitbytes;
188: } else { /* Have to have a separate rootbuf */
189: if (!link->rootbuf_alloc[i][rootmtype]) PetscSFMalloc(sf, rootmtype, bas->rootbuflen[i] * link->unitbytes, (void **)&link->rootbuf_alloc[i][rootmtype]);
190: link->rootbuf[i][rootmtype] = link->rootbuf_alloc[i][rootmtype];
191: }
192: }
194: if (sf->leafbuflen[i]) {
195: if (leafdirect[i]) {
196: link->leafbuf[i][leafmtype] = (char *)leafdata + sf->leafstart[i] * link->unitbytes;
197: } else {
198: if (!link->leafbuf_alloc[i][leafmtype]) PetscSFMalloc(sf, leafmtype, sf->leafbuflen[i] * link->unitbytes, (void **)&link->leafbuf_alloc[i][leafmtype]);
199: link->leafbuf[i][leafmtype] = link->leafbuf_alloc[i][leafmtype];
200: }
201: }
202: }
204: #if defined(PETSC_HAVE_DEVICE)
205: /* Allocate buffers on host for buffering data on device in cast not use_gpu_aware_mpi */
206: if (PetscMemTypeDevice(rootmtype) && PetscMemTypeHost(rootmtype_mpi)) {
207: if (!link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]) PetscMalloc(bas->rootbuflen[PETSCSF_REMOTE] * link->unitbytes, &link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]);
208: link->rootbuf[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST] = link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST];
209: }
210: if (PetscMemTypeDevice(leafmtype) && PetscMemTypeHost(leafmtype_mpi)) {
211: if (!link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]) PetscMalloc(sf->leafbuflen[PETSCSF_REMOTE] * link->unitbytes, &link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]);
212: link->leafbuf[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST] = link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST];
213: }
214: #endif
216: /* Set `current` state of the link. They may change between different SF invocations with the same link */
217: if (sf->persistent) { /* If data is directly passed to MPI and inits MPI requests, record the data for comparison on future invocations */
218: if (rootdirect_mpi) link->rootdatadirect[direction][rootmtype] = rootdata;
219: if (leafdirect_mpi) link->leafdatadirect[direction][leafmtype] = leafdata;
220: }
222: link->rootdata = rootdata; /* root/leafdata are keys to look up links in PetscSFXxxEnd */
223: link->leafdata = leafdata;
224: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
225: link->rootdirect[i] = rootdirect[i];
226: link->leafdirect[i] = leafdirect[i];
227: }
228: link->rootdirect_mpi = rootdirect_mpi;
229: link->leafdirect_mpi = leafdirect_mpi;
230: link->rootmtype = rootmtype;
231: link->leafmtype = leafmtype;
232: link->rootmtype_mpi = rootmtype_mpi;
233: link->leafmtype_mpi = leafmtype_mpi;
235: link->next = bas->inuse;
236: bas->inuse = link;
237: *mylink = link;
238: return 0;
239: }