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: PetscFunctionBegin;
16: buflen = (direction == PETSCSF_../../../../../..2LEAF) ? sf->leafbuflen[PETSCSF_REMOTE] : bas->rootbuflen[PETSCSF_REMOTE];
17: if (buflen) {
18: if (direction == PETSCSF_../../../../../..2LEAF) {
19: nreqs = sf->nleafreqs;
20: PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, NULL, &reqs));
21: } else { /* leaf to root */
22: nreqs = bas->nrootreqs;
23: PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, &reqs, NULL));
24: }
25: PetscCallMPI(MPI_Startall_irecv(buflen, link->unit, nreqs, reqs));
26: }
28: buflen = (direction == PETSCSF_../../../../../..2LEAF) ? bas->rootbuflen[PETSCSF_REMOTE] : sf->leafbuflen[PETSCSF_REMOTE];
29: if (buflen) {
30: if (direction == PETSCSF_../../../../../..2LEAF) {
31: nreqs = bas->nrootreqs;
32: PetscCall(PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE /*device2host before sending */));
33: PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, &reqs, NULL));
34: } else { /* leaf to root */
35: nreqs = sf->nleafreqs;
36: PetscCall(PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE));
37: PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, direction, NULL, NULL, NULL, &reqs));
38: }
39: PetscCall(PetscSFLinkSyncStreamBeforeCallMPI(sf, link, direction));
40: PetscCallMPI(MPI_Startall_isend(buflen, link->unit, nreqs, reqs));
41: }
42: PetscFunctionReturn(PETSC_SUCCESS);
43: }
45: static PetscErrorCode PetscSFLinkWaitRequests_MPI(PetscSF sf, PetscSFLink link, PetscSFDirection direction)
46: {
47: PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
48: const PetscMemType rootmtype_mpi = link->rootmtype_mpi, leafmtype_mpi = link->leafmtype_mpi;
49: const PetscInt rootdirect_mpi = link->rootdirect_mpi, leafdirect_mpi = link->leafdirect_mpi;
51: PetscFunctionBegin;
52: PetscCallMPI(MPI_Waitall(bas->nrootreqs, link->rootreqs[direction][rootmtype_mpi][rootdirect_mpi], MPI_STATUSES_IGNORE));
53: PetscCallMPI(MPI_Waitall(sf->nleafreqs, link->leafreqs[direction][leafmtype_mpi][leafdirect_mpi], MPI_STATUSES_IGNORE));
54: if (direction == PETSCSF_../../../../../..2LEAF) {
55: PetscCall(PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_FALSE /* host2device after recving */));
56: } else {
57: PetscCall(PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_FALSE));
58: }
59: PetscFunctionReturn(PETSC_SUCCESS);
60: }
62: /*
63: The routine Creates a communication link for the given operation. It first looks up its link cache. If
64: there is a free & suitable one, it uses it. Otherwise it creates a new one.
66: A link contains buffers and MPI requests for send/recv. It also contains pack/unpack routines to pack/unpack
67: root/leafdata to/from these buffers. Buffers are allocated at our discretion. When we find root/leafata
68: can be directly passed to MPI, we won't allocate them. Even we allocate buffers, we only allocate
69: those that are needed by the given `sfop` and `op`, in other words, we do lazy memory-allocation.
71: The routine also allocates buffers on CPU when one does not use gpu-aware MPI but data is on GPU.
73: In SFBasic, MPI requests are persistent. They are init'ed until we try to get requests from a link.
75: The routine is shared by SFBasic and SFNeighbor based on the fact they all deal with sparse graphs and
76: need pack/unpack data.
77: */
78: 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)
79: {
80: PetscSF_Basic *bas = (PetscSF_Basic *)sf->data;
81: PetscInt i, j, k, nrootreqs, nleafreqs, nreqs;
82: PetscSFLink *p, link;
83: PetscSFDirection direction;
84: MPI_Request *reqs = NULL;
85: PetscBool match, rootdirect[2], leafdirect[2];
86: PetscMemType rootmtype = PetscMemTypeHost(xrootmtype) ? PETSC_MEMTYPE_HOST : PETSC_MEMTYPE_DEVICE; /* Convert to 0/1 as we will use it in subscript */
87: PetscMemType leafmtype = PetscMemTypeHost(xleafmtype) ? PETSC_MEMTYPE_HOST : PETSC_MEMTYPE_DEVICE;
88: PetscMemType rootmtype_mpi, leafmtype_mpi; /* mtypes seen by MPI */
89: PetscInt rootdirect_mpi, leafdirect_mpi; /* root/leafdirect seen by MPI*/
91: PetscFunctionBegin;
93: /* Can we directly use root/leafdirect with the given sf, sfop and op? */
94: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
95: if (sfop == PETSCSF_BCAST) {
96: rootdirect[i] = bas->rootcontig[i]; /* Pack roots */
97: leafdirect[i] = (sf->leafcontig[i] && op == MPI_REPLACE) ? PETSC_TRUE : PETSC_FALSE; /* Unpack leaves */
98: } else if (sfop == PETSCSF_REDUCE) {
99: leafdirect[i] = sf->leafcontig[i]; /* Pack leaves */
100: rootdirect[i] = (bas->rootcontig[i] && op == MPI_REPLACE) ? PETSC_TRUE : PETSC_FALSE; /* Unpack roots */
101: } else { /* PETSCSF_FETCH */
102: rootdirect[i] = PETSC_FALSE; /* FETCH always need a separate rootbuf */
103: leafdirect[i] = PETSC_FALSE; /* We also force allocating a separate leafbuf so that leafdata and leafupdate can share mpi requests */
104: }
105: }
107: if (sf->use_gpu_aware_mpi) {
108: rootmtype_mpi = rootmtype;
109: leafmtype_mpi = leafmtype;
110: } else {
111: rootmtype_mpi = leafmtype_mpi = PETSC_MEMTYPE_HOST;
112: }
113: /* Will root/leafdata be directly accessed by MPI? Without use_gpu_aware_mpi, device data is buffered on host and then passed to MPI */
114: rootdirect_mpi = rootdirect[PETSCSF_REMOTE] && (rootmtype_mpi == rootmtype) ? 1 : 0;
115: leafdirect_mpi = leafdirect[PETSCSF_REMOTE] && (leafmtype_mpi == leafmtype) ? 1 : 0;
117: direction = (sfop == PETSCSF_BCAST) ? PETSCSF_../../../../../..2LEAF : PETSCSF_LEAF2../../../../../..;
118: nrootreqs = bas->nrootreqs;
119: nleafreqs = sf->nleafreqs;
121: /* Look for free links in cache */
122: for (p = &bas->avail; (link = *p); p = &link->next) {
123: if (!link->use_nvshmem) { /* Only check with MPI links */
124: PetscCall(MPIPetsc_Type_compare(unit, link->unit, &match));
125: if (match) {
126: /* If root/leafdata will be directly passed to MPI, test if the data used to initialized the MPI requests matches with the current.
127: If not, free old requests. New requests will be lazily init'ed until one calls PetscSFLinkGetMPIBuffersAndRequests().
128: */
129: if (rootdirect_mpi && sf->persistent && link->rootreqsinited[direction][rootmtype][1] && link->rootdatadirect[direction][rootmtype] != rootdata) {
130: reqs = link->rootreqs[direction][rootmtype][1]; /* Here, rootmtype = rootmtype_mpi */
131: for (i = 0; i < nrootreqs; i++) {
132: if (reqs[i] != MPI_REQUEST_NULL) PetscCallMPI(MPI_Request_free(&reqs[i]));
133: }
134: link->rootreqsinited[direction][rootmtype][1] = PETSC_FALSE;
135: }
136: if (leafdirect_mpi && sf->persistent && link->leafreqsinited[direction][leafmtype][1] && link->leafdatadirect[direction][leafmtype] != leafdata) {
137: reqs = link->leafreqs[direction][leafmtype][1];
138: for (i = 0; i < nleafreqs; i++) {
139: if (reqs[i] != MPI_REQUEST_NULL) PetscCallMPI(MPI_Request_free(&reqs[i]));
140: }
141: link->leafreqsinited[direction][leafmtype][1] = PETSC_FALSE;
142: }
143: *p = link->next; /* Remove from available list */
144: goto found;
145: }
146: }
147: }
149: PetscCall(PetscNew(&link));
150: PetscCall(PetscSFLinkSetUp_Host(sf, link, unit));
151: PetscCall(PetscCommGetNewTag(PetscObjectComm((PetscObject)sf), &link->tag)); /* One tag per link */
153: nreqs = (nrootreqs + nleafreqs) * 8;
154: PetscCall(PetscMalloc1(nreqs, &link->reqs));
155: 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 */
157: for (i = 0; i < 2; i++) { /* Two communication directions */
158: for (j = 0; j < 2; j++) { /* Two memory types */
159: for (k = 0; k < 2; k++) { /* root/leafdirect 0 or 1 */
160: link->rootreqs[i][j][k] = link->reqs + nrootreqs * (4 * i + 2 * j + k);
161: link->leafreqs[i][j][k] = link->reqs + nrootreqs * 8 + nleafreqs * (4 * i + 2 * j + k);
162: }
163: }
164: }
165: link->StartCommunication = PetscSFLinkStartRequests_MPI;
166: link->FinishCommunication = PetscSFLinkWaitRequests_MPI;
168: found:
170: #if defined(PETSC_HAVE_DEVICE)
171: if ((PetscMemTypeDevice(xrootmtype) || PetscMemTypeDevice(xleafmtype)) && !link->deviceinited) {
172: #if defined(PETSC_HAVE_CUDA)
173: if (sf->backend == PETSCSF_BACKEND_CUDA) PetscCall(PetscSFLinkSetUp_CUDA(sf, link, unit)); /* Setup streams etc */
174: #endif
175: #if defined(PETSC_HAVE_HIP)
176: if (sf->backend == PETSCSF_BACKEND_HIP) PetscCall(PetscSFLinkSetUp_HIP(sf, link, unit)); /* Setup streams etc */
177: #endif
178: #if defined(PETSC_HAVE_KOKKOS)
179: if (sf->backend == PETSCSF_BACKEND_KOKKOS) PetscCall(PetscSFLinkSetUp_Kokkos(sf, link, unit));
180: #endif
181: }
182: #endif
184: /* Allocate buffers along root/leafdata */
185: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
186: /* For local communication, buffers are only needed when roots and leaves have different mtypes */
187: if (i == PETSCSF_LOCAL && rootmtype == leafmtype) continue;
188: if (bas->rootbuflen[i]) {
189: if (rootdirect[i]) { /* Aha, we disguise rootdata as rootbuf */
190: link->rootbuf[i][rootmtype] = (char *)rootdata + bas->rootstart[i] * link->unitbytes;
191: } else { /* Have to have a separate rootbuf */
192: if (!link->rootbuf_alloc[i][rootmtype]) PetscCall(PetscSFMalloc(sf, rootmtype, bas->rootbuflen[i] * link->unitbytes, (void **)&link->rootbuf_alloc[i][rootmtype]));
193: link->rootbuf[i][rootmtype] = link->rootbuf_alloc[i][rootmtype];
194: }
195: }
197: if (sf->leafbuflen[i]) {
198: if (leafdirect[i]) {
199: link->leafbuf[i][leafmtype] = (char *)leafdata + sf->leafstart[i] * link->unitbytes;
200: } else {
201: if (!link->leafbuf_alloc[i][leafmtype]) PetscCall(PetscSFMalloc(sf, leafmtype, sf->leafbuflen[i] * link->unitbytes, (void **)&link->leafbuf_alloc[i][leafmtype]));
202: link->leafbuf[i][leafmtype] = link->leafbuf_alloc[i][leafmtype];
203: }
204: }
205: }
207: #if defined(PETSC_HAVE_DEVICE)
208: /* Allocate buffers on host for buffering data on device in cast not use_gpu_aware_mpi */
209: if (PetscMemTypeDevice(rootmtype) && PetscMemTypeHost(rootmtype_mpi)) {
210: if (!link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]) PetscCall(PetscMalloc(bas->rootbuflen[PETSCSF_REMOTE] * link->unitbytes, &link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]));
211: link->rootbuf[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST] = link->rootbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST];
212: }
213: if (PetscMemTypeDevice(leafmtype) && PetscMemTypeHost(leafmtype_mpi)) {
214: if (!link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]) PetscCall(PetscMalloc(sf->leafbuflen[PETSCSF_REMOTE] * link->unitbytes, &link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST]));
215: link->leafbuf[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST] = link->leafbuf_alloc[PETSCSF_REMOTE][PETSC_MEMTYPE_HOST];
216: }
217: #endif
219: /* Set `current` state of the link. They may change between different SF invocations with the same link */
220: if (sf->persistent) { /* If data is directly passed to MPI and inits MPI requests, record the data for comparison on future invocations */
221: if (rootdirect_mpi) link->rootdatadirect[direction][rootmtype] = rootdata;
222: if (leafdirect_mpi) link->leafdatadirect[direction][leafmtype] = leafdata;
223: }
225: link->rootdata = rootdata; /* root/leafdata are keys to look up links in PetscSFXxxEnd */
226: link->leafdata = leafdata;
227: for (i = PETSCSF_LOCAL; i <= PETSCSF_REMOTE; i++) {
228: link->rootdirect[i] = rootdirect[i];
229: link->leafdirect[i] = leafdirect[i];
230: }
231: link->rootdirect_mpi = rootdirect_mpi;
232: link->leafdirect_mpi = leafdirect_mpi;
233: link->rootmtype = rootmtype;
234: link->leafmtype = leafmtype;
235: link->rootmtype_mpi = rootmtype_mpi;
236: link->leafmtype_mpi = leafmtype_mpi;
238: link->next = bas->inuse;
239: bas->inuse = link;
240: *mylink = link;
241: PetscFunctionReturn(PETSC_SUCCESS);
242: }