MPI 处理文件
最后更新于：2022-04-01 09:51:33
http://www.mcs.anl.gov/research/projects/mpi/usingmpi2/examples/starting/main.htm
下面只是贴了一个基于MPI－1的静态版本的文件的broadcast， 文章中还提供了基于MPI－2的动态版本。
另外还有很全面的MPI的文件处理样式，比如多个node处理同一文件之类的。
master部分的代码
~~~
* pcp from SUT, in MPI */
#include "mpi.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define BUFSIZE 256*1024
#define CMDSIZE 80
int main( int argc, char *argv[] )
{
int mystatus, allstatus, done, numread;
char outfilename[128], controlmsg[80];
int infd, outfd;
char buf[BUFSIZE];
MPI_Init( &argc, &argv );
makehostlist( argv[1], "targets" );
strcpy( outfilename, argv[3] );
if ( (infd = open( argv[2], O_RDONLY ) ) == -1 ) {
fprintf( stderr, "input file %s does not exist\n", argv[2] );
sprintf( controlmsg, "exit" );
MPI_Bcast( controlmsg, CMDSIZE, MPI_CHAR, 0, MPI_COMM_WORLD );
MPI_Finalize();
return( -1 );
}
else {
sprintf( controlmsg, "ready" );
MPI_Bcast( controlmsg, CMDSIZE, MPI_CHAR, 0, MPI_COMM_WORLD );
}
sprintf( controlmsg, outfilename );
MPI_Bcast( controlmsg, CMDSIZE, MPI_CHAR, 0, MPI_COMM_WORLD );
if ( (outfd = open( outfilename, O_CREAT|O_WRONLY|O_TRUNC, S_IRWXU ) ) == -1 )
mystatus = -1;
else
mystatus = 0;
MPI_Allreduce( &mystatus, &allstatus, 1, MPI_INT, MPI_MIN,
MPI_COMM_WORLD );
if ( allstatus == -1 ) {
fprintf( stderr, "output file %s could not be opened\n", outfilename );
MPI_Finalize();
return( -1 );
}
/* at this point all files have been successfully opened */
done = 0;
while ( !done ) {
numread = read( infd, buf, BUFSIZE );
MPI_Bcast( &numread, 1, MPI_INT, 0, MPI_COMM_WORLD );
if ( numread > 0 ) {
MPI_Bcast( buf, numread, MPI_BYTE, 0, MPI_COMM_WORLD );
write( outfd, buf, numread );
}
else {
close( outfd );
done = 1;
}
}
MPI_Finalize();
}
int makehostlist( char spec[80], char filename[80] )
{
}
~~~
slaver部分的代码
~~~
/* pcp from the Scalable Unix Tools, in MPI */
#include "mpi.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define BUFSIZE 256*1024
#define CMDSIZE 80
int main( int argc, char *argv[] )
{
int mystatus, allstatus, done, numread;
char outfilename[128], controlmsg[80];
int outfd;
char buf[BUFSIZE];
MPI_Init( &argc, &argv );
MPI_Bcast( controlmsg, CMDSIZE, MPI_CHAR, 0, MPI_COMM_WORLD );
if ( strcmp( controlmsg, "exit" ) == 0 ) {
MPI_Finalize();
return -1;
}
MPI_Bcast( controlmsg, CMDSIZE, MPI_CHAR, 0, MPI_COMM_WORLD );
if ( (outfd = open( controlmsg, O_CREAT|O_WRONLY|O_TRUNC, S_IRWXU ) ) == -1 )
mystatus = -1;
else
mystatus = 0;
MPI_Allreduce( &mystatus, &allstatus, 1, MPI_INT, MPI_MIN,
MPI_COMM_WORLD );
if ( allstatus == -1 ) {
MPI_Finalize();
return( -1 );
}
/* at this point all files have been successfully opened */
done = 0;
while ( !done ) {
MPI_Bcast( &numread, 1, MPI_INT, 0, MPI_COMM_WORLD );
if ( numread > 0 ) {
MPI_Bcast( buf, numread, MPI_BYTE, 0, MPI_COMM_WORLD );
write( outfd, buf, numread );
}
else {
close( outfd );
done = 1;
}
}
MPI_Finalize();
}
~~~