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feature/Lanczos
Grid/lib/communicator/SharedMemoryMPI.cc
Peter Boyle 12982a4455 Hypercube optimisation
2018-05-02 14:10:21 +01:00

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/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/communicator/SharedMemory.cc
Copyright (C) 2015
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/* END LEGAL */
#include <Grid/GridCore.h>
#include <pwd.h>
namespace Grid {
/*Construct from an MPI communicator*/
void GlobalSharedMemory::Init(Grid_MPI_Comm comm)
{
assert(_ShmSetup==0);
WorldComm = comm;
MPI_Comm_rank(WorldComm,&WorldRank);
MPI_Comm_size(WorldComm,&WorldSize);
// WorldComm, WorldSize, WorldRank
/////////////////////////////////////////////////////////////////////
// Split into groups that can share memory
/////////////////////////////////////////////////////////////////////
MPI_Comm_split_type(comm, MPI_COMM_TYPE_SHARED, 0, MPI_INFO_NULL,&WorldShmComm);
MPI_Comm_rank(WorldShmComm ,&WorldShmRank);
MPI_Comm_size(WorldShmComm ,&WorldShmSize);
// WorldShmComm, WorldShmSize, WorldShmRank
// WorldNodes
WorldNodes = WorldSize/WorldShmSize;
assert( (WorldNodes * WorldShmSize) == WorldSize );
// FIXME: Check all WorldShmSize are the same ?
/////////////////////////////////////////////////////////////////////
// find world ranks in our SHM group (i.e. which ranks are on our node)
/////////////////////////////////////////////////////////////////////
MPI_Group WorldGroup, ShmGroup;
MPI_Comm_group (WorldComm, &WorldGroup);
MPI_Comm_group (WorldShmComm, &ShmGroup);
std::vector<int> world_ranks(WorldSize); for(int r=0;r<WorldSize;r++) world_ranks[r]=r;
WorldShmRanks.resize(WorldSize);
MPI_Group_translate_ranks (WorldGroup,WorldSize,&world_ranks[0],ShmGroup, &WorldShmRanks[0]);
///////////////////////////////////////////////////////////////////
// Identify who is in my group and nominate the leader
///////////////////////////////////////////////////////////////////
int g=0;
std::vector<int> MyGroup;
MyGroup.resize(WorldShmSize);
for(int rank=0;rank<WorldSize;rank++){
if(WorldShmRanks[rank]!=MPI_UNDEFINED){
assert(g<WorldShmSize);
MyGroup[g++] = rank;
}
}
std::sort(MyGroup.begin(),MyGroup.end(),std::less<int>());
int myleader = MyGroup[0];
std::vector<int> leaders_1hot(WorldSize,0);
std::vector<int> leaders_group(WorldNodes,0);
leaders_1hot [ myleader ] = 1;
///////////////////////////////////////////////////////////////////
// global sum leaders over comm world
///////////////////////////////////////////////////////////////////
int ierr=MPI_Allreduce(MPI_IN_PLACE,&leaders_1hot[0],WorldSize,MPI_INT,MPI_SUM,WorldComm);
assert(ierr==0);
///////////////////////////////////////////////////////////////////
// find the group leaders world rank
///////////////////////////////////////////////////////////////////
int group=0;
for(int l=0;l<WorldSize;l++){
if(leaders_1hot[l]){
leaders_group[group++] = l;
}
}
///////////////////////////////////////////////////////////////////
// Identify the node of the group in which I (and my leader) live
///////////////////////////////////////////////////////////////////
WorldNode=-1;
for(int g=0;g<WorldNodes;g++){
if (myleader == leaders_group[g]){
WorldNode=g;
}
}
assert(WorldNode!=-1);
_ShmSetup=1;
}
// Gray encode support
int BinaryToGray (int binary) {
int gray = (binary>>1)^binary;
return gray;
}
int Log2Size(int TwoToPower,int MAXLOG2)
{
int log2size = -1;
for(int i=0;i<=MAXLOG2;i++){
if ( (0x1<<i) == TwoToPower ) {
log2size = i;
break;
}
}
return log2size;
}
void GlobalSharedMemory::OptimalCommunicator(const std::vector<int> &processors,Grid_MPI_Comm & optimal_comm)
{
#undef HYPERCUBE
#ifdef HYPERCUBE
////////////////////////////////////////////////////////////////
// Assert power of two shm_size.
////////////////////////////////////////////////////////////////
int log2size = Log2Size(WorldShmSize,MAXLOG2RANKSPERNODE);
assert(log2size != -1);
////////////////////////////////////////////////////////////////
// Identify the hypercube coordinate of this node using hostname
////////////////////////////////////////////////////////////////
// n runs 0...7 9...16 18...25 27...34 (8*4) 5 bits
// i runs 0..7 3 bits
// r runs 0..3 2 bits
// 2^10 = 1024 nodes
const int maxhdim = 10;
std::vector<int> HyperCubeCoords(maxhdim,0);
std::vector<int> RootHyperCubeCoords(maxhdim,0);
int R;
int I;
int N;
const int namelen = _POSIX_HOST_NAME_MAX;
char name[namelen];
// Parse ICE-XA hostname to get hypercube location
gethostname(name,namelen);
int nscan = sscanf(name,"r%di%dn%d",&R,&I,&N) ;
assert(nscan==3);
int nlo = N%9;
int nhi = N/9;
uint32_t hypercoor = (R<<8)|(I<<5)|(nhi<<3)|nlo ;
uint32_t rootcoor = hypercoor;
//////////////////////////////////////////////////////////////////
// Print debug info
//////////////////////////////////////////////////////////////////
for(int d=0;d<maxhdim;d++){
HyperCubeCoords[d] = (hypercoor>>d)&0x1;
}
std::string hname(name);
std::cout << "hostname "<<hname<<std::endl;
std::cout << "R " << R << " I " << I << " N "<< N<<
<< " hypercoor 0x"<<std::hex<<hypercoor<<std::dec<<std::endl;
//////////////////////////////////////////////////////////////////
// broadcast node 0's base coordinate for this partition.
//////////////////////////////////////////////////////////////////
MPI_Bcast(&rootcoor, sizeof(rootcoor), MPI_BYTE, 0, WorldComm);
hypercoor=hypercoor-rootcoor;
assert(hypercoor<WorldSize);
assert(hypercoor>=0);
//////////////////////////////////////
// Printing
//////////////////////////////////////
for(int d=0;d<maxhdim;d++){
HyperCubeCoords[d] = (hypercoor>>d)&0x1;
}
////////////////////////////////////////////////////////////////
// Identify subblock of ranks on node spreading across dims
// in a maximally symmetrical way
////////////////////////////////////////////////////////////////
int ndimension = processors.size();
std::vector<int> processor_coor(ndimension);
std::vector<int> WorldDims = processors; std::vector<int> ShmDims (ndimension,1); std::vector<int> NodeDims (ndimension);
std::vector<int> ShmCoor (ndimension); std::vector<int> NodeCoor (ndimension); std::vector<int> WorldCoor(ndimension);
std::vector<int> HyperCoor(ndimension);
int dim = 0;
for(int l2=0;l2<log2size;l2++){
while ( (WorldDims[dim] / ShmDims[dim]) <= 1 ) dim=(dim+1)%ndimension;
ShmDims[dim]*=2;
dim=(dim+1)%ndimension;
}
////////////////////////////////////////////////////////////////
// Establish torus of processes and nodes with sub-blockings
////////////////////////////////////////////////////////////////
for(int d=0;d<ndimension;d++){
NodeDims[d] = WorldDims[d]/ShmDims[d];
}
////////////////////////////////////////////////////////////////
// Map Hcube according to physical lattice
// must partition. Loop over dims and find out who would join.
////////////////////////////////////////////////////////////////
int hcoor = hypercoor;
for(int d=0;d<ndimension;d++){
int bits = Log2Size(NodeDims[d],MAXLOG2RANKSPERNODE);
int msk = (0x1<<bits)-1;
HyperCoor[d]=hcoor & msk;
HyperCoor[d]=BinaryToGray(HyperCoor[d]); // Space filling curve magic
hcoor = hcoor >> bits;
}
////////////////////////////////////////////////////////////////
// Check processor counts match
////////////////////////////////////////////////////////////////
int Nprocessors=1;
for(int i=0;i<ndimension;i++){
Nprocessors*=processors[i];
}
assert(WorldSize==Nprocessors);
////////////////////////////////////////////////////////////////
// Establish mapping between lexico physics coord and WorldRank
////////////////////////////////////////////////////////////////
int rank;
Lexicographic::CoorFromIndexReversed(NodeCoor,WorldNode ,NodeDims);
for(int d=0;d<ndimension;d++) NodeCoor[d]=HyperCoor[d];
Lexicographic::CoorFromIndexReversed(ShmCoor ,WorldShmRank,ShmDims);
for(int d=0;d<ndimension;d++) WorldCoor[d] = NodeCoor[d]*ShmDims[d]+ShmCoor[d];
Lexicographic::IndexFromCoorReversed(WorldCoor,rank,WorldDims);
/////////////////////////////////////////////////////////////////
// Build the new communicator
/////////////////////////////////////////////////////////////////
int ierr= MPI_Comm_split(WorldComm,0,rank,&optimal_comm);
assert(ierr==0);
#else
////////////////////////////////////////////////////////////////
// Assert power of two shm_size.
////////////////////////////////////////////////////////////////
int log2size = Log2Size(WorldShmSize,MAXLOG2RANKSPERNODE);
assert(log2size != -1);
////////////////////////////////////////////////////////////////
// Identify subblock of ranks on node spreading across dims
// in a maximally symmetrical way
////////////////////////////////////////////////////////////////
int ndimension = processors.size();
std::vector<int> processor_coor(ndimension);
std::vector<int> WorldDims = processors; std::vector<int> ShmDims (ndimension,1); std::vector<int> NodeDims (ndimension);
std::vector<int> ShmCoor (ndimension); std::vector<int> NodeCoor (ndimension); std::vector<int> WorldCoor(ndimension);
int dim = 0;
for(int l2=0;l2<log2size;l2++){
while ( (WorldDims[dim] / ShmDims[dim]) <= 1 ) dim=(dim+1)%ndimension;
ShmDims[dim]*=2;
dim=(dim+1)%ndimension;
}
////////////////////////////////////////////////////////////////
// Establish torus of processes and nodes with sub-blockings
////////////////////////////////////////////////////////////////
for(int d=0;d<ndimension;d++){
NodeDims[d] = WorldDims[d]/ShmDims[d];
}
////////////////////////////////////////////////////////////////
// Check processor counts match
////////////////////////////////////////////////////////////////
int Nprocessors=1;
for(int i=0;i<ndimension;i++){
Nprocessors*=processors[i];
}
assert(WorldSize==Nprocessors);
////////////////////////////////////////////////////////////////
// Establish mapping between lexico physics coord and WorldRank
////////////////////////////////////////////////////////////////
int rank;
Lexicographic::CoorFromIndexReversed(NodeCoor,WorldNode ,NodeDims);
Lexicographic::CoorFromIndexReversed(ShmCoor ,WorldShmRank,ShmDims);
for(int d=0;d<ndimension;d++) WorldCoor[d] = NodeCoor[d]*ShmDims[d]+ShmCoor[d];
Lexicographic::IndexFromCoorReversed(WorldCoor,rank,WorldDims);
/////////////////////////////////////////////////////////////////
// Build the new communicator
/////////////////////////////////////////////////////////////////
int ierr= MPI_Comm_split(WorldComm,0,rank,&optimal_comm);
assert(ierr==0);
#endif
}
////////////////////////////////////////////////////////////////////////////////////////////
// SHMGET
////////////////////////////////////////////////////////////////////////////////////////////
#ifdef GRID_MPI3_SHMGET
void GlobalSharedMemory::SharedMemoryAllocate(uint64_t bytes, int flags)
{
std::cout << "SharedMemoryAllocate "<< bytes<< " shmget implementation "<<std::endl;
assert(_ShmSetup==1);
assert(_ShmAlloc==0);
//////////////////////////////////////////////////////////////////////////////////////////////////////////
// allocate the shared windows for our group
//////////////////////////////////////////////////////////////////////////////////////////////////////////
MPI_Barrier(WorldShmComm);
WorldShmCommBufs.resize(WorldShmSize);
std::vector<int> shmids(WorldShmSize);
if ( WorldShmRank == 0 ) {
for(int r=0;r<WorldShmSize;r++){
size_t size = bytes;
key_t key = IPC_PRIVATE;
int flags = IPC_CREAT | SHM_R | SHM_W;
#ifdef SHM_HUGETLB
if (Hugepages) flags|=SHM_HUGETLB;
#endif
if ((shmids[r]= shmget(key,size, flags)) ==-1) {
int errsv = errno;
printf("Errno %d\n",errsv);
printf("key %d\n",key);
printf("size %lld\n",size);
printf("flags %d\n",flags);
perror("shmget");
exit(1);
}
}
}
MPI_Barrier(WorldShmComm);
MPI_Bcast(&shmids[0],WorldShmSize*sizeof(int),MPI_BYTE,0,WorldShmComm);
MPI_Barrier(WorldShmComm);
for(int r=0;r<WorldShmSize;r++){
WorldShmCommBufs[r] = (uint64_t *)shmat(shmids[r], NULL,0);
if (WorldShmCommBufs[r] == (uint64_t *)-1) {
perror("Shared memory attach failure");
shmctl(shmids[r], IPC_RMID, NULL);
exit(2);
}
}
MPI_Barrier(WorldShmComm);
///////////////////////////////////
// Mark for clean up
///////////////////////////////////
for(int r=0;r<WorldShmSize;r++){
shmctl(shmids[r], IPC_RMID,(struct shmid_ds *)NULL);
}
MPI_Barrier(WorldShmComm);
_ShmAlloc=1;
_ShmAllocBytes = bytes;
}
#endif
////////////////////////////////////////////////////////////////////////////////////////////
// Hugetlbfs mapping intended
////////////////////////////////////////////////////////////////////////////////////////////
#ifdef GRID_MPI3_SHMMMAP
void GlobalSharedMemory::SharedMemoryAllocate(uint64_t bytes, int flags)
{
std::cout << "SharedMemoryAllocate "<< bytes<< " MMAP implementation "<< GRID_SHM_PATH <<std::endl;
assert(_ShmSetup==1);
assert(_ShmAlloc==0);
//////////////////////////////////////////////////////////////////////////////////////////////////////////
// allocate the shared windows for our group
//////////////////////////////////////////////////////////////////////////////////////////////////////////
MPI_Barrier(WorldShmComm);
WorldShmCommBufs.resize(WorldShmSize);
////////////////////////////////////////////////////////////////////////////////////////////
// Hugetlbfs and others map filesystems as mappable huge pages
////////////////////////////////////////////////////////////////////////////////////////////
char shm_name [NAME_MAX];
for(int r=0;r<WorldShmSize;r++){
sprintf(shm_name,GRID_SHM_PATH "/Grid_mpi3_shm_%d_%d",WorldNode,r);
int fd=open(shm_name,O_RDWR|O_CREAT,0666);
if ( fd == -1) {
printf("open %s failed\n",shm_name);
perror("open hugetlbfs");
exit(0);
}
int mmap_flag = MAP_SHARED ;
#ifdef MAP_POPULATE
mmap_flag|=MAP_POPULATE;
#endif
#ifdef MAP_HUGETLB
if ( flags ) mmap_flag |= MAP_HUGETLB;
#endif
void *ptr = (void *) mmap(NULL, bytes, PROT_READ | PROT_WRITE, mmap_flag,fd, 0);
if ( ptr == (void *)MAP_FAILED ) {
printf("mmap %s failed\n",shm_name);
perror("failed mmap"); assert(0);
}
assert(((uint64_t)ptr&0x3F)==0);
close(fd);
WorldShmCommBufs[r] =ptr;
std::cout << "Set WorldShmCommBufs["<<r<<"]="<<ptr<< "("<< bytes<< "bytes)"<<std::endl;
}
_ShmAlloc=1;
_ShmAllocBytes = bytes;
};
#endif // MMAP
#ifdef GRID_MPI3_SHM_NONE
void GlobalSharedMemory::SharedMemoryAllocate(uint64_t bytes, int flags)
{
std::cout << "SharedMemoryAllocate "<< bytes<< " MMAP anonymous implementation "<<std::endl;
assert(_ShmSetup==1);
assert(_ShmAlloc==0);
//////////////////////////////////////////////////////////////////////////////////////////////////////////
// allocate the shared windows for our group
//////////////////////////////////////////////////////////////////////////////////////////////////////////
MPI_Barrier(WorldShmComm);
WorldShmCommBufs.resize(WorldShmSize);
////////////////////////////////////////////////////////////////////////////////////////////
// Hugetlbf and others map filesystems as mappable huge pages
////////////////////////////////////////////////////////////////////////////////////////////
char shm_name [NAME_MAX];
assert(WorldShmSize == 1);
for(int r=0;r<WorldShmSize;r++){
int fd=-1;
int mmap_flag = MAP_SHARED |MAP_ANONYMOUS ;
#ifdef MAP_POPULATE
mmap_flag|=MAP_POPULATE;
#endif
#ifdef MAP_HUGETLB
if ( flags ) mmap_flag |= MAP_HUGETLB;
#endif
void *ptr = (void *) mmap(NULL, bytes, PROT_READ | PROT_WRITE, mmap_flag,fd, 0);
if ( ptr == (void *)MAP_FAILED ) {
printf("mmap %s failed\n",shm_name);
perror("failed mmap"); assert(0);
}
assert(((uint64_t)ptr&0x3F)==0);
close(fd);
WorldShmCommBufs[r] =ptr;
std::cout << "Set WorldShmCommBufs["<<r<<"]="<<ptr<< "("<< bytes<< "bytes)"<<std::endl;
}
_ShmAlloc=1;
_ShmAllocBytes = bytes;
};
#endif // MMAP
#ifdef GRID_MPI3_SHMOPEN
////////////////////////////////////////////////////////////////////////////////////////////
// POSIX SHMOPEN ; as far as I know Linux does not allow EXPLICIT HugePages with this case
// tmpfs (Larry Meadows says) does not support explicit huge page, and this is used for
// the posix shm virtual file system
////////////////////////////////////////////////////////////////////////////////////////////
void GlobalSharedMemory::SharedMemoryAllocate(uint64_t bytes, int flags)
{
std::cout << "SharedMemoryAllocate "<< bytes<< " SHMOPEN implementation "<<std::endl;
assert(_ShmSetup==1);
assert(_ShmAlloc==0);
MPI_Barrier(WorldShmComm);
WorldShmCommBufs.resize(WorldShmSize);
char shm_name [NAME_MAX];
if ( WorldShmRank == 0 ) {
for(int r=0;r<WorldShmSize;r++){
size_t size = bytes;
struct passwd *pw = getpwuid (getuid());
sprintf(shm_name,"/Grid_%s_mpi3_shm_%d_%d",pw->pw_name,WorldNode,r);
shm_unlink(shm_name);
int fd=shm_open(shm_name,O_RDWR|O_CREAT,0666);
if ( fd < 0 ) { perror("failed shm_open"); assert(0); }
ftruncate(fd, size);
int mmap_flag = MAP_SHARED;
#ifdef MAP_POPULATE
mmap_flag |= MAP_POPULATE;
#endif
#ifdef MAP_HUGETLB
if (flags) mmap_flag |= MAP_HUGETLB;
#endif
void * ptr = mmap(NULL,size, PROT_READ | PROT_WRITE, mmap_flag, fd, 0);
std::cout << "Set WorldShmCommBufs["<<r<<"]="<<ptr<< "("<< size<< "bytes)"<<std::endl;
if ( ptr == (void * )MAP_FAILED ) {
perror("failed mmap");
assert(0);
}
assert(((uint64_t)ptr&0x3F)==0);
WorldShmCommBufs[r] =ptr;
close(fd);
}
}
MPI_Barrier(WorldShmComm);
if ( WorldShmRank != 0 ) {
for(int r=0;r<WorldShmSize;r++){
size_t size = bytes ;
struct passwd *pw = getpwuid (getuid());
sprintf(shm_name,"/Grid_%s_mpi3_shm_%d_%d",pw->pw_name,WorldNode,r);
int fd=shm_open(shm_name,O_RDWR,0666);
if ( fd<0 ) { perror("failed shm_open"); assert(0); }
void * ptr = mmap(NULL,size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if ( ptr == MAP_FAILED ) { perror("failed mmap"); assert(0); }
assert(((uint64_t)ptr&0x3F)==0);
WorldShmCommBufs[r] =ptr;
close(fd);
}
}
_ShmAlloc=1;
_ShmAllocBytes = bytes;
}
#endif
////////////////////////////////////////////////////////
// Global shared functionality finished
// Now move to per communicator functionality
////////////////////////////////////////////////////////
void SharedMemory::SetCommunicator(Grid_MPI_Comm comm)
{
int rank, size;
MPI_Comm_rank(comm,&rank);
MPI_Comm_size(comm,&size);
ShmRanks.resize(size);
/////////////////////////////////////////////////////////////////////
// Split into groups that can share memory
/////////////////////////////////////////////////////////////////////
MPI_Comm_split_type(comm, MPI_COMM_TYPE_SHARED, 0, MPI_INFO_NULL,&ShmComm);
MPI_Comm_rank(ShmComm ,&ShmRank);
MPI_Comm_size(ShmComm ,&ShmSize);
ShmCommBufs.resize(ShmSize);
//////////////////////////////////////////////////////////////////////
// Map ShmRank to WorldShmRank and use the right buffer
//////////////////////////////////////////////////////////////////////
assert (GlobalSharedMemory::ShmAlloc()==1);
heap_size = GlobalSharedMemory::ShmAllocBytes();
for(int r=0;r<ShmSize;r++){
uint32_t wsr = (r==ShmRank) ? GlobalSharedMemory::WorldShmRank : 0 ;
MPI_Allreduce(MPI_IN_PLACE,&wsr,1,MPI_UINT32_T,MPI_SUM,ShmComm);
ShmCommBufs[r] = GlobalSharedMemory::WorldShmCommBufs[wsr];
// std::cout << "SetCommunicator ShmCommBufs ["<< r<< "] = "<< ShmCommBufs[r]<< " wsr = "<<wsr<<std::endl;
}
ShmBufferFreeAll();
/////////////////////////////////////////////////////////////////////
// find comm ranks in our SHM group (i.e. which ranks are on our node)
/////////////////////////////////////////////////////////////////////
MPI_Group FullGroup, ShmGroup;
MPI_Comm_group (comm , &FullGroup);
MPI_Comm_group (ShmComm, &ShmGroup);
std::vector<int> ranks(size); for(int r=0;r<size;r++) ranks[r]=r;
MPI_Group_translate_ranks (FullGroup,size,&ranks[0],ShmGroup, &ShmRanks[0]);
}
//////////////////////////////////////////////////////////////////
// On node barrier
//////////////////////////////////////////////////////////////////
void SharedMemory::ShmBarrier(void)
{
MPI_Barrier (ShmComm);
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////
// Test the shared memory is working
//////////////////////////////////////////////////////////////////////////////////////////////////////////
void SharedMemory::SharedMemoryTest(void)
{
ShmBarrier();
if ( ShmRank == 0 ) {
for(int r=0;r<ShmSize;r++){
uint64_t * check = (uint64_t *) ShmCommBufs[r];
check[0] = GlobalSharedMemory::WorldNode;
check[1] = r;
check[2] = 0x5A5A5A;
}
}
ShmBarrier();
for(int r=0;r<ShmSize;r++){
uint64_t * check = (uint64_t *) ShmCommBufs[r];
assert(check[0]==GlobalSharedMemory::WorldNode);
assert(check[1]==r);
assert(check[2]==0x5A5A5A);
}
ShmBarrier();
}
void *SharedMemory::ShmBuffer(int rank)
{
int gpeer = ShmRanks[rank];
if (gpeer == MPI_UNDEFINED){
return NULL;
} else {
return ShmCommBufs[gpeer];
}
}
void *SharedMemory::ShmBufferTranslate(int rank,void * local_p)
{
static int count =0;
int gpeer = ShmRanks[rank];
assert(gpeer!=ShmRank); // never send to self
if (gpeer == MPI_UNDEFINED){
return NULL;
} else {
uint64_t offset = (uint64_t)local_p - (uint64_t)ShmCommBufs[ShmRank];
uint64_t remote = (uint64_t)ShmCommBufs[gpeer]+offset;
return (void *) remote;
}
}
SharedMemory::~SharedMemory()
{
int MPI_is_finalised; MPI_Finalized(&MPI_is_finalised);
if ( !MPI_is_finalised ) {
MPI_Comm_free(&ShmComm);
}
};
}
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