Skip to content

Commit a3a4787

Browse files
wenduwanwenduwan
committed
coll/libnbc/ialltoallv: skip send/recv 0-byte data
As per MPI specification the amount of data sent must be equal to the amount of data received for each communication pair, and therefore both count and datatype size should be accounted for to determine if the data is 0-byte and therefore skippable. Signed-off-by: Wenduo Wang <wenduwan@amazon.com>
1 parent a7b4d3e commit a3a4787

File tree

1 file changed

+39
-20
lines changed

1 file changed

+39
-20
lines changed

‎ompi/mca/coll/libnbc/nbc_ialltoallv.c

Lines changed: 39 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -48,6 +48,7 @@ static int nbc_alltoallv_init(const void* sendbuf, const int *sendcounts, const
4848
mca_coll_base_module_t *module, bool persistent)
4949
{
5050
int rank, p, res;
51+
size_t sdtype_size, rdtype_size;
5152
MPI_Aint sndext, rcvext;
5253
NBC_Schedule *schedule;
5354
char *rbuf, *sbuf, inplace;
@@ -60,6 +61,7 @@ static int nbc_alltoallv_init(const void* sendbuf, const int *sendcounts, const
6061
rank = ompi_comm_rank (comm);
6162
p = ompi_comm_size (comm);
6263

64+
ompi_datatype_type_size(recvtype, &rdtype_size);
6365
res = ompi_datatype_type_extent (recvtype, &rcvext);
6466
if (MPI_SUCCESS != res) {
6567
NBC_Error("MPI Error in ompi_datatype_type_extent() (%i)", res);
@@ -92,22 +94,29 @@ static int nbc_alltoallv_init(const void* sendbuf, const int *sendcounts, const
9294
sendcounts = recvcounts;
9395
sdispls = rdispls;
9496
sndext = rcvext;
97+
sdtype_size = rdtype_size;
9598
} else {
99+
ompi_datatype_type_size(sendtype, &sdtype_size);
96100
res = ompi_datatype_type_extent (sendtype, &sndext);
97101
if (MPI_SUCCESS != res) {
98102
NBC_Error("MPI Error in ompi_datatype_type_extent() (%i)", res);
99103
return res;
100104
}
101105
}
102106

107+
if (0 == sdtype_size || 0 == rdtype_size) {
108+
/* Nothing to exchange */
109+
ompi_coll_base_nbc_reserve_tags(comm, 1);
110+
return nbc_get_noop_request(persistent, request);
111+
}
112+
103113
schedule = OBJ_NEW(NBC_Schedule);
104114
if (OPAL_UNLIKELY(NULL == schedule)) {
105115
free(tmpbuf);
106116
return OMPI_ERR_OUT_OF_RESOURCE;
107117
}
108118

109-
110-
if (!inplace && sendcounts[rank] != 0) {
119+
if (!inplace && 0 < sendcounts[rank]) {
111120
rbuf = (char *) recvbuf + rdispls[rank] * rcvext;
112121
sbuf = (char *) sendbuf + sdispls[rank] * sndext;
113122
res = NBC_Sched_copy (sbuf, false, sendcounts[rank], sendtype,
@@ -177,10 +186,18 @@ static int nbc_alltoallv_inter_init (const void* sendbuf, const int *sendcounts,
177186
mca_coll_base_module_t *module, bool persistent)
178187
{
179188
int res, rsize;
189+
size_t sdtype_size, rdtype_size;
180190
MPI_Aint sndext, rcvext;
181191
NBC_Schedule *schedule;
182192
ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;
183193

194+
ompi_datatype_type_size(sendtype, &sdtype_size);
195+
ompi_datatype_type_size(recvtype, &rdtype_size);
196+
if (0 == sdtype_size || 0 == rdtype_size) {
197+
/* Nothing to exchange */
198+
ompi_coll_base_nbc_reserve_tags(comm, 1);
199+
return nbc_get_noop_request(persistent, request);
200+
}
184201

185202
res = ompi_datatype_type_extent(sendtype, &sndext);
186203
if (MPI_SUCCESS != res) {
@@ -203,7 +220,7 @@ static int nbc_alltoallv_inter_init (const void* sendbuf, const int *sendcounts,
203220

204221
for (int i = 0; i < rsize; i++) {
205222
/* post all sends */
206-
if (sendcounts[i] != 0) {
223+
if (0 < sendcounts[i]) {
207224
char *sbuf = (char *) sendbuf + sdispls[i] * sndext;
208225
res = NBC_Sched_send (sbuf, false, sendcounts[i], sendtype, i, schedule, false);
209226
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -212,7 +229,7 @@ static int nbc_alltoallv_inter_init (const void* sendbuf, const int *sendcounts,
212229
}
213230
}
214231
/* post all receives */
215-
if (recvcounts[i] != 0) {
232+
if (0 < recvcounts[i]) {
216233
char *rbuf = (char *) recvbuf + rdispls[i] * rcvext;
217234
res = NBC_Sched_recv (rbuf, false, recvcounts[i], recvtype, i, schedule, false);
218235
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -272,7 +289,7 @@ static inline int a2av_sched_linear(int rank, int p, NBC_Schedule *schedule,
272289
}
273290

274291
/* post send */
275-
if (sendcounts[i] != 0) {
292+
if (0 < sendcounts[i]) {
276293
char *sbuf = ((char *) sendbuf) + (sdispls[i] * sndext);
277294
res = NBC_Sched_send(sbuf, false, sendcounts[i], sendtype, i, schedule, false);
278295
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -281,7 +298,7 @@ static inline int a2av_sched_linear(int rank, int p, NBC_Schedule *schedule,
281298
}
282299

283300
/* post receive */
284-
if (recvcounts[i] != 0) {
301+
if (0 < recvcounts[i]) {
285302
char *rbuf = ((char *) recvbuf) + (rdispls[i] * rcvext);
286303
res = NBC_Sched_recv(rbuf, false, recvcounts[i], recvtype, i, schedule, false);
287304
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -306,7 +323,7 @@ static inline int a2av_sched_pairwise(int rank, int p, NBC_Schedule *schedule,
306323
int rcvpeer = (rank + p - i) %p;
307324

308325
/* post send */
309-
if (sendcounts[sndpeer] != 0) {
326+
if (0 < sendcounts[sndpeer]) {
310327
char *sbuf = ((char *) sendbuf) + (sdispls[sndpeer] * sndext);
311328
res = NBC_Sched_send(sbuf, false, sendcounts[sndpeer], sendtype, sndpeer, schedule, false);
312329
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -315,7 +332,7 @@ static inline int a2av_sched_pairwise(int rank, int p, NBC_Schedule *schedule,
315332
}
316333

317334
/* post receive */
318-
if (recvcounts[rcvpeer] != 0) {
335+
if (0 < recvcounts[rcvpeer]) {
319336
char *rbuf = ((char *) recvbuf) + (rdispls[rcvpeer] * rcvext);
320337
res = NBC_Sched_recv(rbuf, false, recvcounts[rcvpeer], recvtype, rcvpeer, schedule, true);
321338
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
@@ -338,34 +355,34 @@ static inline int a2av_sched_inplace(int rank, int p, NBC_Schedule *schedule,
338355
char *sbuf = (char *) buf + displs[speer] * ext;
339356
char *rbuf = (char *) buf + displs[rpeer] * ext;
340357

341-
if (0 != counts[rpeer]) {
358+
if (0 < counts[rpeer]) {
342359
res = NBC_Sched_copy (rbuf, false, counts[rpeer], type,
343360
(void *)(-gap), true, counts[rpeer], type,
344361
schedule, true);
345362
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
346363
return res;
347364
}
348365
}
349-
if (0 != counts[speer]) {
366+
if (0 < counts[speer]) {
350367
res = NBC_Sched_send (sbuf, false , counts[speer], type, speer, schedule, false);
351368
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
352369
return res;
353370
}
354371
}
355-
if (0 != counts[rpeer]) {
372+
if (0 < counts[rpeer]) {
356373
res = NBC_Sched_recv (rbuf, false , counts[rpeer], type, rpeer, schedule, true);
357374
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
358375
return res;
359376
}
360377
}
361378

362-
if (0 != counts[rpeer]) {
379+
if (0 < counts[rpeer]) {
363380
res = NBC_Sched_send ((void *)(-gap), true, counts[rpeer], type, rpeer, schedule, false);
364381
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
365382
return res;
366383
}
367384
}
368-
if (0 != counts[speer]) {
385+
if (0 < counts[speer]) {
369386
res = NBC_Sched_recv (sbuf, false, counts[speer], type, speer, schedule, true);
370387
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
371388
return res;
@@ -374,15 +391,17 @@ static inline int a2av_sched_inplace(int rank, int p, NBC_Schedule *schedule,
374391
}
375392
if (0 == (p%2)) {
376393
int peer = (rank + p/2) % p;
377-
378394
char *tbuf = (char *) buf + displs[peer] * ext;
379-
res = NBC_Sched_copy (tbuf, false, counts[peer], type,
380-
(void *)(-gap), true, counts[peer], type,
381-
schedule, true);
382-
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
383-
return res;
395+
396+
if (0 < counts[peer]) {
397+
res = NBC_Sched_copy(tbuf, false, counts[peer], type, (void *) (-gap), true, counts[peer],
398+
type, schedule, true);
399+
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
400+
return res;
401+
}
384402
}
385-
if (0 != counts[peer]) {
403+
404+
if (0 < counts[peer]) {
386405
res = NBC_Sched_send ((void *)(-gap), true , counts[peer], type, peer, schedule, false);
387406
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
388407
return res;

0 commit comments

Comments
 (0)