ports/openmpi
ports/openmpi
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openmpi/ompi/mca/coll/tuned/coll_tuned_allreduce.c
Nathan Hjelm cf377db823 MCA/base: Add new MCA variable system 
Features:
 - Support for an override parameter file (openmpi-mca-param-override.conf).
   Variable values in this file can not be overridden by any file or environment
   value.
 - Support for boolean, unsigned, and unsigned long long variables.
 - Support for true/false values.
 - Support for enumerations on integer variables.
 - Support for MPIT scope, verbosity, and binding.
 - Support for command line source.
 - Support for setting variable source via the environment using
   OMPI_MCA_SOURCE_<var name>=source (either command or file:filename)
 - Cleaner API.
 - Support for variable groups (equivalent to MPIT categories).

Notes:
 - Variables must be created with a backing store (char **, int *, or bool *)
   that must live at least as long as the variable.
 - Creating a variable with the MCA_BASE_VAR_FLAG_SETTABLE enables the use of
   mca_base_var_set_value() to change the value.
 - String values are duplicated when the variable is registered. It is up to
   the caller to free the original value if necessary. The new value will be
   freed by the mca_base_var system and must not be freed by the user.
 - Variables with constant scope may not be settable.
 - Variable groups (and all associated variables) are deregistered when the
   component is closed or the component repository item is freed. This
   prevents a segmentation fault from accessing a variable after its component
   is unloaded.
 - After some discussion we decided we should remove the automatic registration
   of component priority variables. Few component actually made use of this
   feature.
 - The enumerator interface was updated to be general enough to handle
   future uses of the interface.
 - The code to generate ompi_info output has been moved into the MCA variable
   system. See mca_base_var_dump().

opal: update core and components to mca_base_var system
orte: update core and components to mca_base_var system
ompi: update core and components to mca_base_var system

This commit also modifies the rmaps framework. The following variables were
moved from ppr and lama: rmaps_base_pernode, rmaps_base_n_pernode,
rmaps_base_n_persocket. Both lama and ppr create synonyms for these variables.

This commit was SVN r28236.
2013-03-27 21:09:41 +00:00

1063 строки
50 KiB
C
Исходник Ответственный История

/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil -*- */
/*
* Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
* University Research and Technology
* Corporation. All rights reserved.
* Copyright (c) 2004-2012 The University of Tennessee and The University
* of Tennessee Research Foundation. All rights
* reserved.
* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
* University of Stuttgart. All rights reserved.
* Copyright (c) 2004-2005 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 2009 University of Houston. All rights reserved.
* Copyright (c) 2013 Los Alamos National Security, LLC. All Rights
* reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
#include "ompi_config.h"
#include "mpi.h"
#include "opal/util/bit_ops.h"
#include "ompi/constants.h"
#include "ompi/datatype/ompi_datatype.h"
#include "ompi/communicator/communicator.h"
#include "ompi/mca/coll/coll.h"
#include "ompi/mca/coll/base/coll_tags.h"
#include "ompi/mca/pml/pml.h"
#include "ompi/op/op.h"
#include "coll_tuned.h"
#include "coll_tuned_topo.h"
#include "coll_tuned_util.h"
/* allreduce algorithm variables */
static int coll_tuned_allreduce_algorithm_count = 5;
static int coll_tuned_allreduce_forced_algorithm = 0;
static int coll_tuned_allreduce_segment_size = 0;
static int coll_tuned_allreduce_tree_fanout;
static int coll_tuned_allreduce_chain_fanout;
/* valid values for coll_tuned_allreduce_forced_algorithm */
static mca_base_var_enum_value_t allreduce_algorithms[] = {
{0, "ignore"},
{1, "basic_linear"},
{2, "nonoverlapping"},
{3, "recursive_doubling"},
{4, "ring"},
{5, "segmented_ring"},
{0, NULL}
};
/*
* ompi_coll_tuned_allreduce_intra_nonoverlapping
*
* This function just calls a reduce followed by a broadcast
* both called functions are tuned but they complete sequentially,
* i.e. no additional overlapping
* meaning if the number of segments used is greater than the topo depth
* then once the first segment of data is fully 'reduced' it is not broadcast
* while the reduce continues (cost = cost-reduce + cost-bcast + decision x 3)
*
*/
int
ompi_coll_tuned_allreduce_intra_nonoverlapping(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int err, rank;
rank = ompi_comm_rank(comm);
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_nonoverlapping rank %d", rank));
/* Reduce to 0 and broadcast. */
if (MPI_IN_PLACE == sbuf) {
if (0 == rank) {
err = comm->c_coll.coll_reduce (MPI_IN_PLACE, rbuf, count, dtype,
op, 0, comm, comm->c_coll.coll_reduce_module);
} else {
err = comm->c_coll.coll_reduce (rbuf, NULL, count, dtype, op, 0,
comm, comm->c_coll.coll_reduce_module);
}
} else {
err = comm->c_coll.coll_reduce (sbuf, rbuf, count, dtype, op, 0,
comm, comm->c_coll.coll_reduce_module);
}
if (MPI_SUCCESS != err) {
return err;
}
return comm->c_coll.coll_bcast (rbuf, count, dtype, 0, comm,
comm->c_coll.coll_bcast_module);
}
/*
* ompi_coll_tuned_allreduce_intra_recursivedoubling
*
* Function: Recursive doubling algorithm for allreduce operation
* Accepts: Same as MPI_Allreduce()
* Returns: MPI_SUCCESS or error code
*
* Description: Implements recursive doubling algorithm for allreduce.
* Original (non-segmented) implementation is used in MPICH-2
* for small and intermediate size messages.
* The algorithm preserves order of operations so it can
* be used both by commutative and non-commutative operations.
*
* Example on 7 nodes:
* Initial state
* # 0 1 2 3 4 5 6
* [0] [1] [2] [3] [4] [5] [6]
* Initial adjustment step for non-power of two nodes.
* old rank 1 3 5 6
* new rank 0 1 2 3
* [0+1] [2+3] [4+5] [6]
* Step 1
* old rank 1 3 5 6
* new rank 0 1 2 3
* [0+1+] [0+1+] [4+5+] [4+5+]
* [2+3+] [2+3+] [6 ] [6 ]
* Step 2
* old rank 1 3 5 6
* new rank 0 1 2 3
* [0+1+] [0+1+] [0+1+] [0+1+]
* [2+3+] [2+3+] [2+3+] [2+3+]
* [4+5+] [4+5+] [4+5+] [4+5+]
* [6 ] [6 ] [6 ] [6 ]
* Final adjustment step for non-power of two nodes
* # 0 1 2 3 4 5 6
* [0+1+] [0+1+] [0+1+] [0+1+] [0+1+] [0+1+] [0+1+]
* [2+3+] [2+3+] [2+3+] [2+3+] [2+3+] [2+3+] [2+3+]
* [4+5+] [4+5+] [4+5+] [4+5+] [4+5+] [4+5+] [4+5+]
* [6 ] [6 ] [6 ] [6 ] [6 ] [6 ] [6 ]
*
*/
int
ompi_coll_tuned_allreduce_intra_recursivedoubling(void *sbuf, void *rbuf,
int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int ret, line, rank, size, adjsize, remote, distance;
int newrank, newremote, extra_ranks;
char *tmpsend = NULL, *tmprecv = NULL, *tmpswap = NULL, *inplacebuf = NULL;
ptrdiff_t true_lb, true_extent, lb, extent;
ompi_request_t *reqs[2] = {NULL, NULL};
size = ompi_comm_size(comm);
rank = ompi_comm_rank(comm);
OPAL_OUTPUT((ompi_coll_tuned_stream,
"coll:tuned:allreduce_intra_recursivedoubling rank %d", rank));
/* Special case for size == 1 */
if (1 == size) {
if (MPI_IN_PLACE != sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
return MPI_SUCCESS;
}
/* Allocate and initialize temporary send buffer */
ret = ompi_datatype_get_extent(dtype, &lb, &extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_datatype_get_true_extent(dtype, &true_lb, &true_extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
inplacebuf = (char*) malloc(true_extent + (ptrdiff_t)(count - 1) * extent);
if (NULL == inplacebuf) { ret = -1; line = __LINE__; goto error_hndl; }
if (MPI_IN_PLACE == sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, inplacebuf, (char*)rbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
} else {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, inplacebuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
tmpsend = (char*) inplacebuf;
tmprecv = (char*) rbuf;
/* Determine nearest power of two less than or equal to size */
adjsize = opal_next_poweroftwo (size);
adjsize >>= 1;
/* Handle non-power-of-two case:
- Even ranks less than 2 * extra_ranks send their data to (rank + 1), and
sets new rank to -1.
- Odd ranks less than 2 * extra_ranks receive data from (rank - 1),
apply appropriate operation, and set new rank to rank/2
- Everyone else sets rank to rank - extra_ranks
*/
extra_ranks = size - adjsize;
if (rank < (2 * extra_ranks)) {
if (0 == (rank % 2)) {
ret = MCA_PML_CALL(send(tmpsend, count, dtype, (rank + 1),
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
newrank = -1;
} else {
ret = MCA_PML_CALL(recv(tmprecv, count, dtype, (rank - 1),
MCA_COLL_BASE_TAG_ALLREDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* tmpsend = tmprecv (op) tmpsend */
ompi_op_reduce(op, tmprecv, tmpsend, count, dtype);
newrank = rank >> 1;
}
} else {
newrank = rank - extra_ranks;
}
/* Communication/Computation loop
- Exchange message with remote node.
- Perform appropriate operation taking in account order of operations:
result = value (op) result
*/
for (distance = 0x1; distance < adjsize; distance <<=1) {
if (newrank < 0) break;
/* Determine remote node */
newremote = newrank ^ distance;
remote = (newremote < extra_ranks)?
(newremote * 2 + 1):(newremote + extra_ranks);
/* Exchange the data */
ret = MCA_PML_CALL(irecv(tmprecv, count, dtype, remote,
MCA_COLL_BASE_TAG_ALLREDUCE, comm, &reqs[0]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = MCA_PML_CALL(isend(tmpsend, count, dtype, remote,
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm, &reqs[1]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_request_wait_all(2, reqs, MPI_STATUSES_IGNORE);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Apply operation */
if (rank < remote) {
/* tmprecv = tmpsend (op) tmprecv */
ompi_op_reduce(op, tmpsend, tmprecv, count, dtype);
tmpswap = tmprecv;
tmprecv = tmpsend;
tmpsend = tmpswap;
} else {
/* tmpsend = tmprecv (op) tmpsend */
ompi_op_reduce(op, tmprecv, tmpsend, count, dtype);
}
}
/* Handle non-power-of-two case:
- Odd ranks less than 2 * extra_ranks send result from tmpsend to
(rank - 1)
- Even ranks less than 2 * extra_ranks receive result from (rank + 1)
*/
if (rank < (2 * extra_ranks)) {
if (0 == (rank % 2)) {
ret = MCA_PML_CALL(recv(rbuf, count, dtype, (rank + 1),
MCA_COLL_BASE_TAG_ALLREDUCE, comm,
MPI_STATUS_IGNORE));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
tmpsend = (char*)rbuf;
} else {
ret = MCA_PML_CALL(send(tmpsend, count, dtype, (rank - 1),
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
}
}
/* Ensure that the final result is in rbuf */
if (tmpsend != rbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, tmpsend);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
if (NULL != inplacebuf) free(inplacebuf);
return MPI_SUCCESS;
error_hndl:
OPAL_OUTPUT((ompi_coll_tuned_stream, "%s:%4d\tRank %d Error occurred %d\n",
__FILE__, line, rank, ret));
if (NULL != inplacebuf) free(inplacebuf);
return ret;
}
/*
* ompi_coll_tuned_allreduce_intra_ring
*
* Function: Ring algorithm for allreduce operation
* Accepts: Same as MPI_Allreduce()
* Returns: MPI_SUCCESS or error code
*
* Description: Implements ring algorithm for allreduce: the message is
* automatically segmented to segment of size M/N.
* Algorithm requires 2*N - 1 steps.
*
* Limitations: The algorithm DOES NOT preserve order of operations so it
* can be used only for commutative operations.
* In addition, algorithm cannot work if the total count is
* less than size.
* Example on 5 nodes:
* Initial state
* # 0 1 2 3 4
* [00] [10] [20] [30] [40]
* [01] [11] [21] [31] [41]
* [02] [12] [22] [32] [42]
* [03] [13] [23] [33] [43]
* [04] [14] [24] [34] [44]
*
* COMPUTATION PHASE
* Step 0: rank r sends block r to rank (r+1) and receives bloc (r-1)
* from rank (r-1) [with wraparound].
* # 0 1 2 3 4
* [00] [00+10] [20] [30] [40]
* [01] [11] [11+21] [31] [41]
* [02] [12] [22] [22+32] [42]
* [03] [13] [23] [33] [33+43]
* [44+04] [14] [24] [34] [44]
*
* Step 1: rank r sends block (r-1) to rank (r+1) and receives bloc
* (r-2) from rank (r-1) [with wraparound].
* # 0 1 2 3 4
* [00] [00+10] [01+10+20] [30] [40]
* [01] [11] [11+21] [11+21+31] [41]
* [02] [12] [22] [22+32] [22+32+42]
* [33+43+03] [13] [23] [33] [33+43]
* [44+04] [44+04+14] [24] [34] [44]
*
* Step 2: rank r sends block (r-2) to rank (r+1) and receives bloc
* (r-2) from rank (r-1) [with wraparound].
* # 0 1 2 3 4
* [00] [00+10] [01+10+20] [01+10+20+30] [40]
* [01] [11] [11+21] [11+21+31] [11+21+31+41]
* [22+32+42+02] [12] [22] [22+32] [22+32+42]
* [33+43+03] [33+43+03+13] [23] [33] [33+43]
* [44+04] [44+04+14] [44+04+14+24] [34] [44]
*
* Step 3: rank r sends block (r-3) to rank (r+1) and receives bloc
* (r-3) from rank (r-1) [with wraparound].
* # 0 1 2 3 4
* [00] [00+10] [01+10+20] [01+10+20+30] [FULL]
* [FULL] [11] [11+21] [11+21+31] [11+21+31+41]
* [22+32+42+02] [FULL] [22] [22+32] [22+32+42]
* [33+43+03] [33+43+03+13] [FULL] [33] [33+43]
* [44+04] [44+04+14] [44+04+14+24] [FULL] [44]
*
* DISTRIBUTION PHASE: ring ALLGATHER with ranks shifted by 1.
*
*/
int
ompi_coll_tuned_allreduce_intra_ring(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int ret, line, rank, size, k, recv_from, send_to, block_count, inbi;
int early_segcount, late_segcount, split_rank, max_segcount;
size_t typelng;
char *tmpsend = NULL, *tmprecv = NULL, *inbuf[2] = {NULL, NULL};
ptrdiff_t true_lb, true_extent, lb, extent;
ptrdiff_t block_offset, max_real_segsize;
ompi_request_t *reqs[2] = {NULL, NULL};
size = ompi_comm_size(comm);
rank = ompi_comm_rank(comm);
OPAL_OUTPUT((ompi_coll_tuned_stream,
"coll:tuned:allreduce_intra_ring rank %d, count %d", rank, count));
/* Special case for size == 1 */
if (1 == size) {
if (MPI_IN_PLACE != sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
return MPI_SUCCESS;
}
/* Special case for count less than size - use recursive doubling */
if (count < size) {
OPAL_OUTPUT((ompi_coll_tuned_stream, "coll:tuned:allreduce_ring rank %d/%d, count %d, switching to recursive doubling", rank, size, count));
return (ompi_coll_tuned_allreduce_intra_recursivedoubling(sbuf, rbuf,
count,
dtype, op,
comm, module));
}
/* Allocate and initialize temporary buffers */
ret = ompi_datatype_get_extent(dtype, &lb, &extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_datatype_get_true_extent(dtype, &true_lb, &true_extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_datatype_type_size( dtype, &typelng);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Determine the number of elements per block and corresponding
block sizes.
The blocks are divided into "early" and "late" ones:
blocks 0 .. (split_rank - 1) are "early" and
blocks (split_rank) .. (size - 1) are "late".
Early blocks are at most 1 element larger than the late ones.
*/
COLL_TUNED_COMPUTE_BLOCKCOUNT( count, size, split_rank,
early_segcount, late_segcount )
max_segcount = early_segcount;
max_real_segsize = true_extent + (max_segcount - 1) * extent;
inbuf[0] = (char*)malloc(max_real_segsize);
if (NULL == inbuf[0]) { ret = -1; line = __LINE__; goto error_hndl; }
if (size > 2) {
inbuf[1] = (char*)malloc(max_real_segsize);
if (NULL == inbuf[1]) { ret = -1; line = __LINE__; goto error_hndl; }
}
/* Handle MPI_IN_PLACE */
if (MPI_IN_PLACE != sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
/* Computation loop */
/*
For each of the remote nodes:
- post irecv for block (r-1)
- send block (r)
- in loop for every step k = 2 .. n
- post irecv for block (r + n - k) % n
- wait on block (r + n - k + 1) % n to arrive
- compute on block (r + n - k + 1) % n
- send block (r + n - k + 1) % n
- wait on block (r + 1)
- compute on block (r + 1)
- send block (r + 1) to rank (r + 1)
Note that we must be careful when computing the begining of buffers and
for send operations and computation we must compute the exact block size.
*/
send_to = (rank + 1) % size;
recv_from = (rank + size - 1) % size;
inbi = 0;
/* Initialize first receive from the neighbor on the left */
ret = MCA_PML_CALL(irecv(inbuf[inbi], max_segcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE, comm, &reqs[inbi]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Send first block (my block) to the neighbor on the right */
block_offset = ((rank < split_rank)?
((ptrdiff_t)rank * (ptrdiff_t)early_segcount) :
((ptrdiff_t)rank * (ptrdiff_t)late_segcount + split_rank));
block_count = ((rank < split_rank)? early_segcount : late_segcount);
tmpsend = ((char*)rbuf) + block_offset * extent;
ret = MCA_PML_CALL(send(tmpsend, block_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
for (k = 2; k < size; k++) {
const int prevblock = (rank + size - k + 1) % size;
inbi = inbi ^ 0x1;
/* Post irecv for the current block */
ret = MCA_PML_CALL(irecv(inbuf[inbi], max_segcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE, comm, &reqs[inbi]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Wait on previous block to arrive */
ret = ompi_request_wait(&reqs[inbi ^ 0x1], MPI_STATUS_IGNORE);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Apply operation on previous block: result goes to rbuf
rbuf[prevblock] = inbuf[inbi ^ 0x1] (op) rbuf[prevblock]
*/
block_offset = ((prevblock < split_rank)?
((ptrdiff_t)prevblock * early_segcount) :
((ptrdiff_t)prevblock * late_segcount + split_rank));
block_count = ((prevblock < split_rank)? early_segcount : late_segcount);
tmprecv = ((char*)rbuf) + (ptrdiff_t)block_offset * extent;
ompi_op_reduce(op, inbuf[inbi ^ 0x1], tmprecv, block_count, dtype);
/* send previous block to send_to */
ret = MCA_PML_CALL(send(tmprecv, block_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
}
/* Wait on the last block to arrive */
ret = ompi_request_wait(&reqs[inbi], MPI_STATUS_IGNORE);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Apply operation on the last block (from neighbor (rank + 1)
rbuf[rank+1] = inbuf[inbi] (op) rbuf[rank + 1] */
recv_from = (rank + 1) % size;
block_offset = ((recv_from < split_rank)?
((ptrdiff_t)recv_from * early_segcount) :
((ptrdiff_t)recv_from * late_segcount + split_rank));
block_count = ((recv_from < split_rank)? early_segcount : late_segcount);
tmprecv = ((char*)rbuf) + (ptrdiff_t)block_offset * extent;
ompi_op_reduce(op, inbuf[inbi], tmprecv, block_count, dtype);
/* Distribution loop - variation of ring allgather */
send_to = (rank + 1) % size;
recv_from = (rank + size - 1) % size;
for (k = 0; k < size - 1; k++) {
const int recv_data_from = (rank + size - k) % size;
const int send_data_from = (rank + 1 + size - k) % size;
const int send_block_offset =
((send_data_from < split_rank)?
((ptrdiff_t)send_data_from * early_segcount) :
((ptrdiff_t)send_data_from * late_segcount + split_rank));
const int recv_block_offset =
((recv_data_from < split_rank)?
((ptrdiff_t)recv_data_from * early_segcount) :
((ptrdiff_t)recv_data_from * late_segcount + split_rank));
block_count = ((send_data_from < split_rank)?
early_segcount : late_segcount);
tmprecv = (char*)rbuf + (ptrdiff_t)recv_block_offset * extent;
tmpsend = (char*)rbuf + (ptrdiff_t)send_block_offset * extent;
ret = ompi_coll_tuned_sendrecv(tmpsend, block_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
tmprecv, max_segcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE,
comm, MPI_STATUS_IGNORE, rank);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl;}
}
if (NULL != inbuf[0]) free(inbuf[0]);
if (NULL != inbuf[1]) free(inbuf[1]);
return MPI_SUCCESS;
error_hndl:
OPAL_OUTPUT((ompi_coll_tuned_stream, "%s:%4d\tRank %d Error occurred %d\n",
__FILE__, line, rank, ret));
if (NULL != inbuf[0]) free(inbuf[0]);
if (NULL != inbuf[1]) free(inbuf[1]);
return ret;
}
/*
* ompi_coll_tuned_allreduce_intra_ring_segmented
*
* Function: Pipelined ring algorithm for allreduce operation
* Accepts: Same as MPI_Allreduce(), segment size
* Returns: MPI_SUCCESS or error code
*
* Description: Implements pipelined ring algorithm for allreduce:
* user supplies suggested segment size for the pipelining of
* reduce operation.
* The segment size determines the number of phases, np, for
* the algorithm execution.
* The message is automatically divided into blocks of
* approximately (count / (np * segcount)) elements.
* At the end of reduction phase, allgather like step is
* executed.
* Algorithm requires (np + 1)*(N - 1) steps.
*
* Limitations: The algorithm DOES NOT preserve order of operations so it
* can be used only for commutative operations.
* In addition, algorithm cannot work if the total size is
* less than size * segment size.
* Example on 3 nodes with 2 phases
* Initial state
* # 0 1 2
* [00a] [10a] [20a]
* [00b] [10b] [20b]
* [01a] [11a] [21a]
* [01b] [11b] [21b]
* [02a] [12a] [22a]
* [02b] [12b] [22b]
*
* COMPUTATION PHASE 0 (a)
* Step 0: rank r sends block ra to rank (r+1) and receives bloc (r-1)a
* from rank (r-1) [with wraparound].
* # 0 1 2
* [00a] [00a+10a] [20a]
* [00b] [10b] [20b]
* [01a] [11a] [11a+21a]
* [01b] [11b] [21b]
* [22a+02a] [12a] [22a]
* [02b] [12b] [22b]
*
* Step 1: rank r sends block (r-1)a to rank (r+1) and receives bloc
* (r-2)a from rank (r-1) [with wraparound].
* # 0 1 2
* [00a] [00a+10a] [00a+10a+20a]
* [00b] [10b] [20b]
* [11a+21a+01a] [11a] [11a+21a]
* [01b] [11b] [21b]
* [22a+02a] [22a+02a+12a] [22a]
* [02b] [12b] [22b]
*
* COMPUTATION PHASE 1 (b)
* Step 0: rank r sends block rb to rank (r+1) and receives bloc (r-1)b
* from rank (r-1) [with wraparound].
* # 0 1 2
* [00a] [00a+10a] [20a]
* [00b] [00b+10b] [20b]
* [01a] [11a] [11a+21a]
* [01b] [11b] [11b+21b]
* [22a+02a] [12a] [22a]
* [22b+02b] [12b] [22b]
*
* Step 1: rank r sends block (r-1)b to rank (r+1) and receives bloc
* (r-2)b from rank (r-1) [with wraparound].
* # 0 1 2
* [00a] [00a+10a] [00a+10a+20a]
* [00b] [10b] [0bb+10b+20b]
* [11a+21a+01a] [11a] [11a+21a]
* [11b+21b+01b] [11b] [21b]
* [22a+02a] [22a+02a+12a] [22a]
* [02b] [22b+01b+12b] [22b]
*
*
* DISTRIBUTION PHASE: ring ALLGATHER with ranks shifted by 1 (same as
* in regular ring algorithm.
*
*/
int
ompi_coll_tuned_allreduce_intra_ring_segmented(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module,
uint32_t segsize)
{
int ret, line, rank, size, k, recv_from, send_to;
int early_blockcount, late_blockcount, split_rank;
int segcount, max_segcount, num_phases, phase, block_count, inbi;
size_t typelng;
char *tmpsend = NULL, *tmprecv = NULL, *inbuf[2] = {NULL, NULL};
ptrdiff_t true_lb, true_extent, lb, extent;
ptrdiff_t block_offset, max_real_segsize;
ompi_request_t *reqs[2] = {NULL, NULL};
size = ompi_comm_size(comm);
rank = ompi_comm_rank(comm);
OPAL_OUTPUT((ompi_coll_tuned_stream,
"coll:tuned:allreduce_intra_ring_segmented rank %d, count %d", rank, count));
/* Special case for size == 1 */
if (1 == size) {
if (MPI_IN_PLACE != sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
return MPI_SUCCESS;
}
/* Determine segment count based on the suggested segment size */
ret = ompi_datatype_get_extent(dtype, &lb, &extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_datatype_get_true_extent(dtype, &true_lb, &true_extent);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
ret = ompi_datatype_type_size( dtype, &typelng);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
segcount = count;
COLL_TUNED_COMPUTED_SEGCOUNT(segsize, typelng, segcount)
/* Special case for count less than size * segcount - use regular ring */
if (count < (size * segcount)) {
OPAL_OUTPUT((ompi_coll_tuned_stream, "coll:tuned:allreduce_ring_segmented rank %d/%d, count %d, switching to regular ring", rank, size, count));
return (ompi_coll_tuned_allreduce_intra_ring(sbuf, rbuf, count, dtype, op,
comm, module));
}
/* Determine the number of phases of the algorithm */
num_phases = count / (size * segcount);
if ((count % (size * segcount) >= size) &&
(count % (size * segcount) > ((size * segcount) / 2))) {
num_phases++;
}
/* Determine the number of elements per block and corresponding
block sizes.
The blocks are divided into "early" and "late" ones:
blocks 0 .. (split_rank - 1) are "early" and
blocks (split_rank) .. (size - 1) are "late".
Early blocks are at most 1 element larger than the late ones.
Note, these blocks will be split into num_phases segments,
out of the largest one will have max_segcount elements.
*/
COLL_TUNED_COMPUTE_BLOCKCOUNT( count, size, split_rank,
early_blockcount, late_blockcount )
COLL_TUNED_COMPUTE_BLOCKCOUNT( early_blockcount, num_phases, inbi,
max_segcount, k)
max_real_segsize = true_extent + (ptrdiff_t)(max_segcount - 1) * extent;
/* Allocate and initialize temporary buffers */
inbuf[0] = (char*)malloc(max_real_segsize);
if (NULL == inbuf[0]) { ret = -1; line = __LINE__; goto error_hndl; }
if (size > 2) {
inbuf[1] = (char*)malloc(max_real_segsize);
if (NULL == inbuf[1]) { ret = -1; line = __LINE__; goto error_hndl; }
}
/* Handle MPI_IN_PLACE */
if (MPI_IN_PLACE != sbuf) {
ret = ompi_datatype_copy_content_same_ddt(dtype, count, (char*)rbuf, (char*)sbuf);
if (ret < 0) { line = __LINE__; goto error_hndl; }
}
/* Computation loop: for each phase, repeat ring allreduce computation loop */
for (phase = 0; phase < num_phases; phase ++) {
ptrdiff_t phase_offset;
int early_phase_segcount, late_phase_segcount, split_phase, phase_count;
/*
For each of the remote nodes:
- post irecv for block (r-1)
- send block (r)
To do this, first compute block offset and count, and use block offset
to compute phase offset.
- in loop for every step k = 2 .. n
- post irecv for block (r + n - k) % n
- wait on block (r + n - k + 1) % n to arrive
- compute on block (r + n - k + 1) % n
- send block (r + n - k + 1) % n
- wait on block (r + 1)
- compute on block (r + 1)
- send block (r + 1) to rank (r + 1)
Note that we must be careful when computing the begining of buffers and
for send operations and computation we must compute the exact block size.
*/
send_to = (rank + 1) % size;
recv_from = (rank + size - 1) % size;
inbi = 0;
/* Initialize first receive from the neighbor on the left */
ret = MCA_PML_CALL(irecv(inbuf[inbi], max_segcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE, comm, &reqs[inbi]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Send first block (my block) to the neighbor on the right:
- compute my block and phase offset
- send data */
block_offset = ((rank < split_rank)?
((ptrdiff_t)rank * (ptrdiff_t)early_blockcount) :
((ptrdiff_t)rank * (ptrdiff_t)late_blockcount + split_rank));
block_count = ((rank < split_rank)? early_blockcount : late_blockcount);
COLL_TUNED_COMPUTE_BLOCKCOUNT(block_count, num_phases, split_phase,
early_phase_segcount, late_phase_segcount)
phase_count = ((phase < split_phase)?
(early_phase_segcount) : (late_phase_segcount));
phase_offset = ((phase < split_phase)?
((ptrdiff_t)phase * (ptrdiff_t)early_phase_segcount) :
((ptrdiff_t)phase * (ptrdiff_t)late_phase_segcount + split_phase));
tmpsend = ((char*)rbuf) + (ptrdiff_t)(block_offset + phase_offset) * extent;
ret = MCA_PML_CALL(send(tmpsend, phase_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
for (k = 2; k < size; k++) {
const int prevblock = (rank + size - k + 1) % size;
inbi = inbi ^ 0x1;
/* Post irecv for the current block */
ret = MCA_PML_CALL(irecv(inbuf[inbi], max_segcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE, comm,
&reqs[inbi]));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Wait on previous block to arrive */
ret = ompi_request_wait(&reqs[inbi ^ 0x1], MPI_STATUS_IGNORE);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Apply operation on previous block: result goes to rbuf
rbuf[prevblock] = inbuf[inbi ^ 0x1] (op) rbuf[prevblock]
*/
block_offset = ((prevblock < split_rank)?
((ptrdiff_t)prevblock * (ptrdiff_t)early_blockcount) :
((ptrdiff_t)prevblock * (ptrdiff_t)late_blockcount + split_rank));
block_count = ((prevblock < split_rank)?
early_blockcount : late_blockcount);
COLL_TUNED_COMPUTE_BLOCKCOUNT(block_count, num_phases, split_phase,
early_phase_segcount, late_phase_segcount)
phase_count = ((phase < split_phase)?
(early_phase_segcount) : (late_phase_segcount));
phase_offset = ((phase < split_phase)?
((ptrdiff_t)phase * (ptrdiff_t)early_phase_segcount) :
((ptrdiff_t)phase * (ptrdiff_t)late_phase_segcount + split_phase));
tmprecv = ((char*)rbuf) + (ptrdiff_t)(block_offset + phase_offset) * extent;
ompi_op_reduce(op, inbuf[inbi ^ 0x1], tmprecv, phase_count, dtype);
/* send previous block to send_to */
ret = MCA_PML_CALL(send(tmprecv, phase_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
MCA_PML_BASE_SEND_STANDARD, comm));
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
}
/* Wait on the last block to arrive */
ret = ompi_request_wait(&reqs[inbi], MPI_STATUS_IGNORE);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl; }
/* Apply operation on the last block (from neighbor (rank + 1)
rbuf[rank+1] = inbuf[inbi] (op) rbuf[rank + 1] */
recv_from = (rank + 1) % size;
block_offset = ((recv_from < split_rank)?
((ptrdiff_t)recv_from * (ptrdiff_t)early_blockcount) :
((ptrdiff_t)recv_from * (ptrdiff_t)late_blockcount + split_rank));
block_count = ((recv_from < split_rank)?
early_blockcount : late_blockcount);
COLL_TUNED_COMPUTE_BLOCKCOUNT(block_count, num_phases, split_phase,
early_phase_segcount, late_phase_segcount)
phase_count = ((phase < split_phase)?
(early_phase_segcount) : (late_phase_segcount));
phase_offset = ((phase < split_phase)?
((ptrdiff_t)phase * (ptrdiff_t)early_phase_segcount) :
((ptrdiff_t)phase * (ptrdiff_t)late_phase_segcount + split_phase));
tmprecv = ((char*)rbuf) + (ptrdiff_t)(block_offset + phase_offset) * extent;
ompi_op_reduce(op, inbuf[inbi], tmprecv, phase_count, dtype);
}
/* Distribution loop - variation of ring allgather */
send_to = (rank + 1) % size;
recv_from = (rank + size - 1) % size;
for (k = 0; k < size - 1; k++) {
const int recv_data_from = (rank + size - k) % size;
const int send_data_from = (rank + 1 + size - k) % size;
const int send_block_offset =
((send_data_from < split_rank)?
((ptrdiff_t)send_data_from * (ptrdiff_t)early_blockcount) :
((ptrdiff_t)send_data_from * (ptrdiff_t)late_blockcount + split_rank));
const int recv_block_offset =
((recv_data_from < split_rank)?
((ptrdiff_t)recv_data_from * (ptrdiff_t)early_blockcount) :
((ptrdiff_t)recv_data_from * (ptrdiff_t)late_blockcount + split_rank));
block_count = ((send_data_from < split_rank)?
early_blockcount : late_blockcount);
tmprecv = (char*)rbuf + (ptrdiff_t)recv_block_offset * extent;
tmpsend = (char*)rbuf + (ptrdiff_t)send_block_offset * extent;
ret = ompi_coll_tuned_sendrecv(tmpsend, block_count, dtype, send_to,
MCA_COLL_BASE_TAG_ALLREDUCE,
tmprecv, early_blockcount, dtype, recv_from,
MCA_COLL_BASE_TAG_ALLREDUCE,
comm, MPI_STATUS_IGNORE, rank);
if (MPI_SUCCESS != ret) { line = __LINE__; goto error_hndl;}
}
if (NULL != inbuf[0]) free(inbuf[0]);
if (NULL != inbuf[1]) free(inbuf[1]);
return MPI_SUCCESS;
error_hndl:
OPAL_OUTPUT((ompi_coll_tuned_stream, "%s:%4d\tRank %d Error occurred %d\n",
__FILE__, line, rank, ret));
if (NULL != inbuf[0]) free(inbuf[0]);
if (NULL != inbuf[1]) free(inbuf[1]);
return ret;
}
/*
* Linear functions are copied from the BASIC coll module
* they do not segment the message and are simple implementations
* but for some small number of nodes and/or small data sizes they
* are just as fast as tuned/tree based segmenting operations
* and as such may be selected by the decision functions
* These are copied into this module due to the way we select modules
* in V1. i.e. in V2 we will handle this differently and so will not
* have to duplicate code.
* GEF Oct05 after asking Jeff.
*/
/* copied function (with appropriate renaming) starts here */
/*
* allreduce_intra
*
* Function: - allreduce using other MPI collectives
* Accepts: - same as MPI_Allreduce()
* Returns: - MPI_SUCCESS or error code
*/
int
ompi_coll_tuned_allreduce_intra_basic_linear(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
int err, rank;
rank = ompi_comm_rank(comm);
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_basic_linear rank %d", rank));
/* Reduce to 0 and broadcast. */
if (MPI_IN_PLACE == sbuf) {
if (0 == rank) {
err = ompi_coll_tuned_reduce_intra_basic_linear (MPI_IN_PLACE, rbuf, count, dtype,
op, 0, comm, module);
} else {
err = ompi_coll_tuned_reduce_intra_basic_linear(rbuf, NULL, count, dtype,
op, 0, comm, module);
}
} else {
err = ompi_coll_tuned_reduce_intra_basic_linear(sbuf, rbuf, count, dtype,
op, 0, comm, module);
}
if (MPI_SUCCESS != err) {
return err;
}
return ompi_coll_tuned_bcast_intra_basic_linear(rbuf, count, dtype, 0, comm, module);
}
/* copied function (with appropriate renaming) ends here */
/* The following are used by dynamic and forced rules */
/* publish details of each algorithm and if its forced/fixed/locked in */
/* as you add methods/algorithms you must update this and the query/map routines */
/* this routine is called by the component only */
/* this makes sure that the mca parameters are set to their initial values and perms */
/* module does not call this they call the forced_getvalues routine instead */
int ompi_coll_tuned_allreduce_intra_check_forced_init (coll_tuned_force_algorithm_mca_param_indices_t *mca_param_indices)
{
mca_base_var_enum_t *new_enum;
ompi_coll_tuned_forced_max_algorithms[ALLREDUCE] = coll_tuned_allreduce_algorithm_count;
(void) mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
"allreduce_algorithm_count",
"Number of allreduce algorithms available",
MCA_BASE_VAR_TYPE_INT, NULL, 0,
MCA_BASE_VAR_FLAG_DEFAULT_ONLY,
OPAL_INFO_LVL_5,
MCA_BASE_VAR_SCOPE_CONSTANT,
&coll_tuned_allreduce_algorithm_count);
/* MPI_T: This variable should eventually be bound to a communicator */
coll_tuned_allreduce_forced_algorithm = 0;
(void) mca_base_var_enum_create("coll_tuned_allreduce_algorithms", allreduce_algorithms, &new_enum);
mca_param_indices->algorithm_param_index =
mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
"allreduce_algorithm",
"Which allreduce algorithm is used. Can be locked down to any of: 0 ignore, 1 basic linear, 2 nonoverlapping (tuned reduce + tuned bcast), 3 recursive doubling, 4 ring, 5 segmented ring",
MCA_BASE_VAR_TYPE_INT, new_enum, 0, 0,
OPAL_INFO_LVL_5,
MCA_BASE_VAR_SCOPE_READONLY,
&coll_tuned_allreduce_forced_algorithm);
OBJ_RELEASE(new_enum);
if (mca_param_indices->algorithm_param_index < 0) {
return mca_param_indices->algorithm_param_index;
}
coll_tuned_allreduce_segment_size = 0;
mca_param_indices->segsize_param_index =
mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
"allreduce_algorithm_segmentsize",
"Segment size in bytes used by default for allreduce algorithms. Only has meaning if algorithm is forced and supports segmenting. 0 bytes means no segmentation.",
MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
OPAL_INFO_LVL_5,
MCA_BASE_VAR_SCOPE_READONLY,
&coll_tuned_allreduce_segment_size);
coll_tuned_allreduce_tree_fanout = ompi_coll_tuned_init_tree_fanout; /* get system wide default */
mca_param_indices->tree_fanout_param_index =
mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
"allreduce_algorithm_tree_fanout",
"Fanout for n-tree used for allreduce algorithms. Only has meaning if algorithm is forced and supports n-tree topo based operation.",
MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
OPAL_INFO_LVL_5,
MCA_BASE_VAR_SCOPE_READONLY,
&coll_tuned_allreduce_tree_fanout);
coll_tuned_allreduce_chain_fanout = ompi_coll_tuned_init_chain_fanout; /* get system wide default */
mca_param_indices->chain_fanout_param_index =
mca_base_component_var_register(&mca_coll_tuned_component.super.collm_version,
"allreduce_algorithm_chain_fanout",
"Fanout for chains used for allreduce algorithms. Only has meaning if algorithm is forced and supports chain topo based operation.",
MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
OPAL_INFO_LVL_5,
MCA_BASE_VAR_SCOPE_READONLY,
&coll_tuned_allreduce_chain_fanout);
return (MPI_SUCCESS);
}
int ompi_coll_tuned_allreduce_intra_do_forced(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module)
{
mca_coll_tuned_module_t *tuned_module = (mca_coll_tuned_module_t*) module;
mca_coll_tuned_comm_t *data = tuned_module->tuned_data;
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_do_forced selected algorithm %d, segment size %d",
data->user_forced[ALLREDUCE].algorithm,
data->user_forced[ALLREDUCE].segsize));
switch (data->user_forced[ALLREDUCE].algorithm) {
case (0): return ompi_coll_tuned_allreduce_intra_dec_fixed (sbuf, rbuf, count, dtype, op, comm, module);
case (1): return ompi_coll_tuned_allreduce_intra_basic_linear (sbuf, rbuf, count, dtype, op, comm, module);
case (2): return ompi_coll_tuned_allreduce_intra_nonoverlapping (sbuf, rbuf, count, dtype, op, comm, module);
case (3): return ompi_coll_tuned_allreduce_intra_recursivedoubling (sbuf, rbuf, count, dtype, op, comm, module);
case (4): return ompi_coll_tuned_allreduce_intra_ring (sbuf, rbuf, count, dtype, op, comm, module);
case (5): return ompi_coll_tuned_allreduce_intra_ring_segmented (sbuf, rbuf, count, dtype, op, comm, module, data->user_forced[ALLREDUCE].segsize);
default:
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_do_forced attempt to select algorithm %d when only 0-%d is valid?",
data->user_forced[ALLREDUCE].algorithm,
ompi_coll_tuned_forced_max_algorithms[ALLREDUCE]));
return (MPI_ERR_ARG);
} /* switch */
}
int ompi_coll_tuned_allreduce_intra_do_this(void *sbuf, void *rbuf, int count,
struct ompi_datatype_t *dtype,
struct ompi_op_t *op,
struct ompi_communicator_t *comm,
mca_coll_base_module_t *module,
int algorithm, int faninout, int segsize)
{
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_do_this algorithm %d topo fan in/out %d segsize %d",
algorithm, faninout, segsize));
switch (algorithm) {
case (0): return ompi_coll_tuned_allreduce_intra_dec_fixed (sbuf, rbuf, count, dtype, op, comm, module);
case (1): return ompi_coll_tuned_allreduce_intra_basic_linear (sbuf, rbuf, count, dtype, op, comm, module);
case (2): return ompi_coll_tuned_allreduce_intra_nonoverlapping (sbuf, rbuf, count, dtype, op, comm, module);
case (3): return ompi_coll_tuned_allreduce_intra_recursivedoubling (sbuf, rbuf, count, dtype, op, comm, module);
case (4): return ompi_coll_tuned_allreduce_intra_ring (sbuf, rbuf, count, dtype, op, comm, module);
case (5): return ompi_coll_tuned_allreduce_intra_ring_segmented (sbuf, rbuf, count, dtype, op, comm, module, segsize);
default:
OPAL_OUTPUT((ompi_coll_tuned_stream,"coll:tuned:allreduce_intra_do_this attempt to select algorithm %d when only 0-%d is valid?",
algorithm, ompi_coll_tuned_forced_max_algorithms[ALLREDUCE]));
return (MPI_ERR_ARG);
} /* switch */
}
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