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/*********************************************************************
*
* Copyright (C) 2018, Northwestern University and Argonne National Laboratory
* See COPYRIGHT notice in top-level directory.
*
*********************************************************************/
/* $Id$ */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* This example shows how to create/open the file using the burst buffer driver.
* It is a modified version of create_open.c under examples/C using the burst buffer driver.
*
* To compile:
* mpicc -O2 create_open.c -o create_open -lpnetcdf
*
* Example commands for MPI run and outputs from running ncmpidump on the
* netCDF file produced by this example program:
*
* % mpiexec -n 4 ./create_open -b /scratch testfile.nc
* create_open.c: example of file create and open
*
* % ncmpidump testfile.nc
* netcdf testfile {
* // file format: CDF-1
* }
*
* Example batch script for running on Cori at NERSC using SLURM scheduler
*
* #!/bin/bash
* #SBATCH -p debug
* #SBATCH -N 1
* #SBATCH -C haswell
* #SBATCH -t 00:01:00
* #SBATCH -o create_open_example.txt
* #SBATCH -L scratch
* #DW jobdw capacity=1289GiB access_mode=private type=scratch pool=sm_pool
* srun -n 4 ./create_open -b $DW_JOB_PRIVATE $SCRATCH/testfile.nc
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* strcpy(), strncpy(), strdup() */
#include <unistd.h> /* getopt() */
#include <mpi.h>
#include <pnetcdf.h>
#define ERR {if(err!=NC_NOERR){printf("Error at line %d in %s: %s\n", __LINE__,__FILE__, ncmpi_strerror(err));nerrs++;}}
static void
usage(char *argv0)
{
char *help =
"Usage: %s [-h] | [-q] [-b bb_dir] file_name\n"
" [-h] Print help\n"
" [-q] Quiet mode (reports when fail)\n"
" [-b bb_dir] Path to burst buffer\n"
" filename: output netCDF file name\n";
fprintf(stderr, help, argv0);
}
int main(int argc, char** argv)
{
extern int optind;
extern char *optarg;
char filename[256], *bb_dir;
int i, rank, verbose=1, err, nerrs=0, ncid;
MPI_Info info;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
/* get command-line arguments */
bb_dir = strdup(".");
while ((i = getopt(argc, argv, "hqb:")) != EOF)
switch(i) {
case 'q': verbose = 0;
break;
case 'h':
case 'b': free(bb_dir);
bb_dir = strdup(optarg);
break;
default: if (rank==0) usage(argv[0]);
MPI_Finalize();
return 1;
}
if (argv[optind] == NULL) strcpy(filename, "testfile.nc");
else snprintf(filename, 256, "%s", argv[optind]);
if (verbose && rank == 0) printf("%s: example of file create and open\n",__FILE__);
/* Set up the hints for burst buffer driver in ncmpi_create
* Note that the remaining part of the code remains unchanged
* The burst buffer driver will not proceed if the log files already exists
* to prevent overwriting existing files by accident
* To open the file again, we need to delete the log file after file closing
* The default value of nc_burst_buf_del_on_close is enable, we set it for the
* purpose of demonstration.
* PnetCDF will warn if nc_burst_buf_dirname is not set.
*/
MPI_Info_create(&info);
MPI_Info_set(info, "nc_burst_buf", "enable");
MPI_Info_set(info, "nc_burst_buf_del_on_close", "enable");
MPI_Info_set(info, "nc_burst_buf_dirname", bb_dir);
/* create a new file using clobber mode ----------------------------------*/
err = ncmpi_create(MPI_COMM_WORLD, filename, NC_CLOBBER, info, &ncid); ERR
/* Info can be freed after file creation */
MPI_Info_free(&info);
if (err != NC_NOERR) goto fn_exit;
/* burst buffer initialize log files on the first time we enters data mode */
err = ncmpi_enddef(ncid);
ERR
/* close file */
err = ncmpi_close(ncid);
ERR
/* Set up the hints for burst buffer driver in ncmpi_create
* Note that the remaining part of the code remains unchanged
* PnetCDF will warn if nc_burst_buf_dirname is not set.
*/
MPI_Info_create(&info);
MPI_Info_set(info, "nc_burst_buf", "enable");
MPI_Info_set(info, "nc_burst_buf_dirname", bb_dir);
free(bb_dir);
/* open the newly created file for read only -----------------------------*/
err = ncmpi_open(MPI_COMM_WORLD, filename, NC_WRITE, info, &ncid);
ERR
/* Info can be freed after file opening */
MPI_Info_free(&info);
if (err != NC_NOERR) goto fn_exit;
/* close file */
err = ncmpi_close(ncid);
ERR
/* check if there is any PnetCDF internal malloc residue */
MPI_Offset malloc_size, sum_size;
err = ncmpi_inq_malloc_size(&malloc_size);
if (err == NC_NOERR) {
MPI_Reduce(&malloc_size, &sum_size, 1, MPI_OFFSET, MPI_SUM, 0, MPI_COMM_WORLD);
if (rank == 0 && sum_size > 0)
printf("heap memory allocated by PnetCDF internally has %lld bytes yet to be freed\n",
sum_size);
}
fn_exit:
MPI_Finalize();
return (nerrs > 0);
}
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