1 /* Copyright (c) 2010-2019. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 #ifndef SMPI_FILE_HPP_INCLUDED
8 #define SMPI_FILE_HPP_INCLUDED
9 #include "simgrid/plugins/file_system.h"
10 #include "smpi_comm.hpp"
11 #include "smpi_coll.hpp"
12 #include "smpi_datatype.hpp"
13 #include "smpi_info.hpp"
16 XBT_LOG_EXTERNAL_CATEGORY(smpi_pmpi);
23 simgrid::s4u::File* file_;
25 MPI_Offset* shared_file_pointer_;
26 s4u::MutexPtr shared_mutex_;
30 File(MPI_Comm comm, char *filename, int amode, MPI_Info info);
31 File(const File&) = delete;
32 File& operator=(const File&) = delete;
35 int get_position(MPI_Offset* offset);
36 int get_position_shared(MPI_Offset* offset);
39 int seek(MPI_Offset offset, int whence);
40 int seek_shared(MPI_Offset offset, int whence);
42 void set_info( MPI_Info info);
43 static int read(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
44 static int read_shared(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
45 static int read_ordered(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
46 static int write(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
47 static int write_shared(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
48 static int write_ordered(MPI_File fh, void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
49 template <int (*T)(MPI_File, void *, int, MPI_Datatype, MPI_Status *)> int op_all(void *buf, int count,MPI_Datatype datatype, MPI_Status *status);
50 static int close(MPI_File *fh);
51 static int del(char *filename, MPI_Info info);
54 /* Read_all, Write_all : loosely based on */
55 /* @article{Thakur:1996:ETM:245875.245879,*/
56 /* author = {Thakur, Rajeev and Choudhary, Alok},*/
57 /* title = {An Extended Two-phase Method for Accessing Sections of Out-of-core Arrays},*/
58 /* journal = {Sci. Program.},*/
59 /* issue_date = {Winter 1996},*/
60 /* pages = {301--317},*/
62 template <int (*T)(MPI_File, void *, int, MPI_Datatype, MPI_Status *)>
63 int File::op_all(void *buf, int count, MPI_Datatype datatype, MPI_Status *status){
64 //get min and max offsets from everyone.
65 int size = comm_->size();
66 int rank = comm_-> rank();
67 MPI_Offset min_offset = file_->tell();
68 MPI_Offset max_offset = (min_offset + count * datatype->size());//cheating, as we don't care about exact data location, we can skip extent
69 MPI_Offset* min_offsets = xbt_new(MPI_Offset, size);
70 MPI_Offset* max_offsets = xbt_new(MPI_Offset, size);
71 simgrid::smpi::Colls::allgather(&min_offset, 1, MPI_OFFSET, min_offsets, 1, MPI_OFFSET, comm_);
72 simgrid::smpi::Colls::allgather(&max_offset, 1, MPI_OFFSET, max_offsets, 1, MPI_OFFSET, comm_);
73 MPI_Offset min=min_offset;
74 MPI_Offset max=max_offset;
77 for(int i=0;i<size;i++){
78 if(min_offsets[i]!=max_offsets[i])
80 tot+=(max_offsets[i]-min_offsets[i]);
81 if(min_offsets[i]<min)
83 if(max_offsets[i]>max)
87 XBT_CDEBUG(smpi_pmpi, "my offsets to read : %lld:%lld, global min and max %lld:%lld", min_offset, max_offset, min, max);
92 MPI_Offset total = max-min;
93 if(total==tot && (datatype->flags() & DT_FLAG_CONTIGUOUS)){
94 //contiguous. Just have each proc perform its read
95 status->count=count * datatype->size();
96 return T(this,buf,count,datatype, status);
99 //Interleaved case : How much do I need to read, and whom to send it ?
100 MPI_Offset my_chunk_start=(max-min+1)/size*rank;
101 MPI_Offset my_chunk_end=((max-min+1)/size*(rank+1));
102 XBT_CDEBUG(smpi_pmpi, "my chunks to read : %lld:%lld", my_chunk_start, my_chunk_end);
103 int* send_sizes = xbt_new0(int, size);
104 int* recv_sizes = xbt_new(int, size);
105 int* send_disps = xbt_new(int, size);
106 int* recv_disps = xbt_new(int, size);
108 for(int i=0;i<size;i++){
109 if((my_chunk_start>=min_offsets[i] && my_chunk_start < max_offsets[i])||
110 ((my_chunk_end<=max_offsets[i]) && my_chunk_end> min_offsets[i])){
111 send_sizes[i]=(std::min(max_offsets[i]-1, my_chunk_end-1)-std::max(min_offsets[i], my_chunk_start));
112 //store min and max offest to actually read
113 min_offset=std::min(min_offset, min_offsets[i]);
114 send_disps[i]=0;//send_sizes[i]; cheat to avoid issues when send>recv as we use recv buffer
115 total_sent+=send_sizes[i];
116 XBT_CDEBUG(smpi_pmpi, "will have to send %d bytes to %d", send_sizes[i], i);
119 min_offset=std::max(min_offset, my_chunk_start);
121 //merge the ranges of every process
122 std::vector<std::pair<MPI_Offset, MPI_Offset>> ranges;
123 for(int i=0; i<size; ++i)
124 ranges.push_back(std::make_pair(min_offsets[i],max_offsets[i]));
125 std::sort(ranges.begin(), ranges.end());
126 std::vector<std::pair<MPI_Offset, MPI_Offset>> chunks;
127 chunks.push_back(ranges[0]);
129 unsigned int nchunks=0;
131 while(i < ranges.size()){
132 if(ranges[i].second>chunks[nchunks].second){
133 // else range included - ignore
134 if(ranges[i].first>chunks[nchunks].second){
136 chunks.push_back(ranges[i]);
140 chunks[nchunks].second=ranges[i].second;
145 //what do I need to read ?
146 MPI_Offset totreads=0;
147 for(i=0; i<chunks.size();i++){
148 if(chunks[i].second < my_chunk_start)
150 else if (chunks[i].first > my_chunk_end)
153 totreads += (std::min(chunks[i].second, my_chunk_end-1)-std::max(chunks[i].first, my_chunk_start));
155 XBT_CDEBUG(smpi_pmpi, "will have to access %lld from my chunk", totreads);
157 char* sendbuf= static_cast<char *>(smpi_get_tmp_sendbuffer(total_sent));
160 seek(min_offset, MPI_SEEK_SET);
161 T(this,sendbuf,totreads/datatype->size(),datatype, status);
163 simgrid::smpi::Colls::alltoall(send_sizes, 1, MPI_INT, recv_sizes, 1, MPI_INT, comm_);
165 for(int i=0;i<size;i++){
166 recv_disps[i]=total_recv;
167 total_recv+=recv_sizes[i];
169 //Set buf value to avoid copying dumb data
170 simgrid::smpi::Colls::alltoallv(sendbuf, send_sizes, send_disps, MPI_BYTE,
171 buf, recv_sizes, recv_disps, MPI_BYTE, comm_);
172 status->count=count * datatype->size();
173 smpi_free_tmp_buffer(sendbuf);
174 xbt_free(send_sizes);
175 xbt_free(recv_sizes);
176 xbt_free(send_disps);
177 xbt_free(recv_disps);
178 xbt_free(min_offsets);
179 xbt_free(max_offsets);