File io 如何用MPI_file_open替换MPI中的现有文件
我正在阅读“使用MPI-2”,并尝试自己执行代码。我为MPI_File_open指定了MPI_MODE_CREATE,但它实际上并不创建新文件,而是用相同的名称覆盖以前的文件。当我第一次运行更多的进程,然后运行更少的进程时,我碰巧发现了这一点。我的MPI版本是openmpi 1.8.1 这是密码File io 如何用MPI_file_open替换MPI中的现有文件,file-io,operating-system,filesystems,mpi,hpc,File Io,Operating System,Filesystems,Mpi,Hpc,我正在阅读“使用MPI-2”,并尝试自己执行代码。我为MPI_File_open指定了MPI_MODE_CREATE,但它实际上并不创建新文件,而是用相同的名称覆盖以前的文件。当我第一次运行更多的进程,然后运行更少的进程时,我碰巧发现了这一点。我的MPI版本是openmpi 1.8.1 这是密码 #include <stdio.h> #include <mpi.h> #define BUFSIZE 4 int main(int argc, char **argv) {
#include <stdio.h>
#include <mpi.h>
#define BUFSIZE 4
int main(int argc, char **argv)
{
int map[BUFSIZE], i, rank , size;
char buf[BUFSIZE];
MPI_File fh;
MPI_Datatype filetype;
MPI_Status status;
MPI_Offset disp=0;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
for(i=0;i<BUFSIZE;i++)
{
// buf[i]=size*i+rank+'0';
buf[i]=size*i+rank+'A';
map[i]=size*i+rank;
}
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
MPI_Type_create_indexed_block(BUFSIZE, 1, map, MPI_CHAR, &filetype);
MPI_Type_commit(&filetype);
MPI_File_set_view(fh, disp, MPI_CHAR, filetype, "native", MPI_INFO_NULL);
MPI_File_write_all(fh, buf, BUFSIZE, MPI_CHAR, &status);
MPI_File_close(&fh);
MPI_Type_free(&filetype);
MPI_Finalize();
return 0;
}
然后我修改了一点。替代品
buf[i]=size*i+rank+'A';
与
并运行2个进程,文件如下
01234567IJKLMNOPQRSTUVWX
这是正确的行为-MPI_MODE_CREATE“”,如果这样做则无效;正如文档所说,与相应的POSIX完全相同 无论出于何种原因,没有一个MPI_MODE_*等价于O_TRUNC,如果文件已经存在,它会对文件进行重击;为此,您必须使用
MPI_MODE_CREATE | MPI_MODE_EXCL
打开文件,检查打开是否失败,如果失败,请删除文件并重复(或者在关闭时使用MPI_MODE_delete_打开文件,关闭它,然后重新打开它)
通过两种方式对其进行编码:
#include <stdio.h>
#include <mpi.h>
#define BUFSIZE 4
int main(int argc, char **argv)
{
int map[BUFSIZE], i, rank , size;
char buf[BUFSIZE];
MPI_File fh;
MPI_Datatype filetype;
MPI_Status status;
MPI_Offset disp=0;
if (argc != 3) {
fprintf(stderr,"Usage: %s letters|numbers test|delete|none\n", argv[0]);
exit(-1);
}
int letters=0;
if (!strcasecmp(argv[1],"letters"))
letters = 1;
int test=0;
if (!strcasecmp(argv[2],"test"))
test = 1;
int delete = 0;
if (!strcasecmp(argv[2],"delete"))
delete = 1;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
for(i=0;i<BUFSIZE;i++)
{
if (letters)
buf[i]=size*i+rank+'A';
else
buf[i]=size*i+rank+'0';
map[i]=size*i+rank;
}
if (test) {
int err = MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
if (err != MPI_SUCCESS) {
if (rank == 0)
MPI_File_delete("datafile4",MPI_INFO_NULL);
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
}
} else if (delete) {
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_DELETE_ON_CLOSE|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
MPI_File_close(&fh);
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
} else {
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
}
MPI_Type_create_indexed_block(BUFSIZE, 1, map, MPI_CHAR, &filetype);
MPI_Type_commit(&filetype);
MPI_File_set_view(fh, disp, MPI_CHAR, filetype, "native", MPI_INFO_NULL);
MPI_File_write_all(fh, buf, BUFSIZE, MPI_CHAR, &status);
MPI_File_close(&fh);
MPI_Type_free(&filetype);
MPI_Finalize();
return 0;
}
谢谢你的回答!顺便问一下,为什么输出文件中的字符串后面有$符号?这是提示;在数据的末尾没有换行符(这在MPI-IO的常用用例中很好)。我只是在这些行之后按回车键,否则读起来会很混乱。
01234567IJKLMNOPQRSTUVWX
#include <stdio.h>
#include <mpi.h>
#define BUFSIZE 4
int main(int argc, char **argv)
{
int map[BUFSIZE], i, rank , size;
char buf[BUFSIZE];
MPI_File fh;
MPI_Datatype filetype;
MPI_Status status;
MPI_Offset disp=0;
if (argc != 3) {
fprintf(stderr,"Usage: %s letters|numbers test|delete|none\n", argv[0]);
exit(-1);
}
int letters=0;
if (!strcasecmp(argv[1],"letters"))
letters = 1;
int test=0;
if (!strcasecmp(argv[2],"test"))
test = 1;
int delete = 0;
if (!strcasecmp(argv[2],"delete"))
delete = 1;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
for(i=0;i<BUFSIZE;i++)
{
if (letters)
buf[i]=size*i+rank+'A';
else
buf[i]=size*i+rank+'0';
map[i]=size*i+rank;
}
if (test) {
int err = MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
if (err != MPI_SUCCESS) {
if (rank == 0)
MPI_File_delete("datafile4",MPI_INFO_NULL);
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
}
} else if (delete) {
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_DELETE_ON_CLOSE|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
MPI_File_close(&fh);
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_EXCL|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
} else {
MPI_File_open(MPI_COMM_WORLD, "datafile4", MPI_MODE_CREATE|MPI_MODE_WRONLY, MPI_INFO_NULL, &fh);
}
MPI_Type_create_indexed_block(BUFSIZE, 1, map, MPI_CHAR, &filetype);
MPI_Type_commit(&filetype);
MPI_File_set_view(fh, disp, MPI_CHAR, filetype, "native", MPI_INFO_NULL);
MPI_File_write_all(fh, buf, BUFSIZE, MPI_CHAR, &status);
MPI_File_close(&fh);
MPI_Type_free(&filetype);
MPI_Finalize();
return 0;
}
# just open CREATE|WRONLY, reproduce result above
$ mpirun -np 6 ./clobber letters none
$ cat datafile4
ABCDEFGHIJKLMNOPQRSTUVWX$
$ mpirun -np 2 ./clobber numbers none
$ cat datafile4
01234567IJKLMNOPQRSTUVWX$
# test for failed EXCL open, and if so, remove file:
$ mpirun -np 6 ./clobber letters test
$ cat datafile4
ABCDEFGHIJKLMNOPQRSTUVWX$
$ mpirun -np 2 ./clobber numbers test
$ cat datafile4
01234567$
# or always open delete-on-close, close, then re-open
$ mpirun -np 6 ./clobber letters delete
$ cat datafile4
ABCDEFGHIJKLMNOPQRSTUVWX$
$ mpirun -np 2 ./clobber numbers delete
$ cat datafile4
01234567$