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v2.0.x: add support for MPI_IN_PLACE in MPI_Ialltoall* #2236

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Merged
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Oct 18, 2016
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v2.0.x: add support for MPI_IN_PLACE in MPI_Ialltoall* #2236

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150eafd
coll/libnbc: implement support for MPI_IN_PLACE in MPI_Ialltoall*
ggouaillardet Oct 5, 2016
2a55cb1
ompi: accept MPI_IN_PLACE in MPI_Ialltoall*
ggouaillardet Oct 5, 2016
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88 changes: 76 additions & 12 deletions ompi/mca/coll/libnbc/nbc_ialltoall.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@
* Copyright (c) 2013-2015 Los Alamos National Security, LLC. All rights
* reserved.
* Copyright (c) 2014 NVIDIA Corporation. All rights reserved.
* Copyright (c) 2014-2015 Research Organization for Information Science
* Copyright (c) 2014-2016 Research Organization for Information Science
* and Technology (RIST). All rights reserved.
*
* Author(s): Torsten Hoefler <htor@cs.indiana.edu>
Expand All @@ -25,6 +25,8 @@ static inline int a2a_sched_pairwise(int rank, int p, MPI_Aint sndext, MPI_Aint
static inline int a2a_sched_diss(int rank, int p, MPI_Aint sndext, MPI_Aint rcvext, NBC_Schedule* schedule,
const void* sendbuf, int sendcount, MPI_Datatype sendtype, void* recvbuf,
int recvcount, MPI_Datatype recvtype, MPI_Comm comm, NBC_Handle *handle);
static inline int a2a_sched_inplace(int rank, int p, NBC_Schedule* schedule, void* buf, int count,
MPI_Datatype type, MPI_Aint ext, ptrdiff_t gap, MPI_Comm comm);

#ifdef NBC_CACHE_SCHEDULE
/* tree comparison function for schedule cache */
Expand Down Expand Up @@ -59,9 +61,10 @@ int ompi_coll_libnbc_ialltoall(const void* sendbuf, int sendcount, MPI_Datatype
NBC_Alltoall_args *args, *found, search;
#endif
char *rbuf, *sbuf, inplace;
enum {NBC_A2A_LINEAR, NBC_A2A_PAIRWISE, NBC_A2A_DISS} alg;
enum {NBC_A2A_LINEAR, NBC_A2A_PAIRWISE, NBC_A2A_DISS, NBC_A2A_INPLACE} alg;
NBC_Handle *handle;
ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;
ptrdiff_t span, gap;

NBC_IN_PLACE(sendbuf, recvbuf, inplace);

Expand Down Expand Up @@ -89,7 +92,9 @@ int ompi_coll_libnbc_ialltoall(const void* sendbuf, int sendcount, MPI_Datatype
/* algorithm selection */
a2asize = sndsize * sendcount * p;
/* this number is optimized for TCP on odin.cs.indiana.edu */
if((p <= 8) && ((a2asize < 1<<17) || (sndsize*sendcount < 1<<12))) {
if (inplace) {
alg = NBC_A2A_INPLACE;
} else if((p <= 8) && ((a2asize < 1<<17) || (sndsize*sendcount < 1<<12))) {
/* just send as fast as we can if we have less than 8 peers, if the
* total communicated size is smaller than 1<<17 *and* if we don't
* have eager messages (msgsize < 1<<13) */
Expand All @@ -116,7 +121,14 @@ int ompi_coll_libnbc_ialltoall(const void* sendbuf, int sendcount, MPI_Datatype
}

/* allocate temp buffer if we need one */
if (alg == NBC_A2A_DISS) {
if (alg == NBC_A2A_INPLACE) {
span = opal_datatype_span(&recvtype->super, recvcount, &gap);
handle->tmpbuf = malloc(span);
if (OPAL_UNLIKELY(NULL == handle->tmpbuf)) {
NBC_Return_handle (handle);
return OMPI_ERR_OUT_OF_RESOURCE;
}
} else if (alg == NBC_A2A_DISS) {
/* only A2A_DISS needs buffers */
if(NBC_Type_intrinsic(sendtype)) {
datasize = sndext * sendcount;
Expand Down Expand Up @@ -200,6 +212,9 @@ int ompi_coll_libnbc_ialltoall(const void* sendbuf, int sendcount, MPI_Datatype
handle->schedule = schedule;

switch(alg) {
case NBC_A2A_INPLACE:
res = a2a_sched_inplace(rank, p, schedule, recvbuf, recvcount, recvtype, rcvext, gap, comm);
break;
case NBC_A2A_LINEAR:
res = a2a_sched_linear(rank, p, sndext, rcvext, schedule, sendbuf, sendcount, sendtype, recvbuf, recvcount, recvtype, comm);
break;
Expand Down Expand Up @@ -359,17 +374,10 @@ static inline int a2a_sched_pairwise(int rank, int p, MPI_Aint sndext, MPI_Aint
}

char *sbuf = (char *) sendbuf + sndpeer * sendcount * sndext;
res = NBC_Sched_send (sbuf, false, sendcount, sendtype, sndpeer, schedule, false);
res = NBC_Sched_send (sbuf, false, sendcount, sendtype, sndpeer, schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}

if (r < p) {
res = NBC_Sched_barrier (schedule);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
}
}

return OMPI_SUCCESS;
Expand Down Expand Up @@ -497,3 +505,59 @@ static inline int a2a_sched_diss(int rank, int p, MPI_Aint sndext, MPI_Aint rcve
return OMPI_SUCCESS;
}

static inline int a2a_sched_inplace(int rank, int p, NBC_Schedule* schedule, void* buf, int count,
MPI_Datatype type, MPI_Aint ext, ptrdiff_t gap, MPI_Comm comm) {
int res;

for (int i = 1 ; i < (p+1)/2 ; i++) {
int speer = (rank + i) % p;
int rpeer = (rank + p - i) % p;
char *sbuf = (char *) buf + speer * count * ext;
char *rbuf = (char *) buf + rpeer * count * ext;

res = NBC_Sched_copy (rbuf, false, count, type,
(void *)(-gap), true, count, type,
schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
res = NBC_Sched_send (sbuf, false , count, type, speer, schedule, false);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
res = NBC_Sched_recv (rbuf, false , count, type, rpeer, schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}

res = NBC_Sched_send ((void *)(-gap), true, count, type, rpeer, schedule, false);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
res = NBC_Sched_recv (sbuf, false, count, type, speer, schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
}
if (0 == (p%2)) {
int peer = (rank + p/2) % p;

char *tbuf = (char *) buf + peer * count * ext;
res = NBC_Sched_copy (tbuf, false, count, type,
(void *)(-gap), true, count, type,
schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
res = NBC_Sched_send ((void *)(-gap), true , count, type, peer, schedule, false);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
res = NBC_Sched_recv (tbuf, false , count, type, peer, schedule, true);
if (OPAL_UNLIKELY(OMPI_SUCCESS != res)) {
return res;
}
}

return OMPI_SUCCESS;
}
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