openmpi/ompi/mca/fbtl/plfs/fbtl_plfs_preadv.c

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2011 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * Copyright (c) 2008-2014 University of Houston. All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#include "ompi_config.h"
#include "fbtl_plfs.h"

#include "mpi.h"
#include <unistd.h>
#include "ompi/constants.h"
#include "ompi/mca/fbtl/fbtl.h"

size_t 
mca_fbtl_plfs_preadv (mca_io_ompio_file_t *fh,
                       int *sorted)
{

    Plfs_fd *pfd = NULL;
    plfs_error_t plfs_ret;
    pfd = fh->f_fs_ptr;

    int i, block=1;
    struct iovec *iov = NULL;
    int iov_count = 0;
    OMPI_MPI_OFFSET_TYPE iov_offset = 0;

    if (NULL == fh->f_io_array) {
        return OMPI_ERROR;
    }

    iov = (struct iovec *) malloc 
        (OMPIO_IOVEC_INITIAL_SIZE * sizeof (struct iovec));
    if (NULL == iov) {
        opal_output(1, "OUT OF MEMORY\n");
        return OMPI_ERR_OUT_OF_RESOURCE;
    }

    if (NULL != sorted) {
        for (i=0 ; i<fh->f_num_of_io_entries ; i++) {
            if (0 == iov_count) {
                iov[iov_count].iov_base = fh->f_io_array[sorted[i]].memory_address;
                iov[iov_count].iov_len = fh->f_io_array[sorted[i]].length;
                iov_offset = (OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[sorted[i]].offset;
                iov_count ++;
            }

            if (OMPIO_IOVEC_INITIAL_SIZE*block <= iov_count) {
                block ++;
                iov = (struct iovec *)realloc
                    (iov, OMPIO_IOVEC_INITIAL_SIZE * block *
                     sizeof(struct iovec));
                if (NULL == iov) {
                    opal_output(1, "OUT OF MEMORY\n");
                    return OMPI_ERR_OUT_OF_RESOURCE;
                }
            }

            if (fh->f_num_of_io_entries != i+1) {
	      if (((OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[sorted[i]].offset + 
                     (OPAL_PTRDIFF_TYPE)fh->f_io_array[sorted[i]].length) == 
		  (OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[sorted[i+1]].offset) {                    
                    iov[iov_count].iov_base = 
                        fh->f_io_array[sorted[i+1]].memory_address;
                    iov[iov_count].iov_len = fh->f_io_array[sorted[i+1]].length;
                    iov_count ++;
                    continue;
                }
            }

	    // Find the total number of bytes to be read.
	    size_t bytes = 0;
	    for (int i = 0; i < iov_count; ++i) {
		bytes += iov[i].iov_len;
	    }

	    // Allocate a temporary buffer to hold the data
	    char *buffer;
	    buffer = (char *) malloc (bytes);
	    if (buffer == NULL) {
	        return OMPI_ERROR;
	    }

	    // Read the data
	    ssize_t bytes_read;

	    plfs_ret = plfs_read( pfd, buffer, bytes, iov_offset, &bytes_read );
	    if (PLFS_SUCCESS != plfs_ret) {
	        opal_output(0, "fbtl_plfs_preadv: Error in plfs_read:\n%s\n", strplfserr(plfs_ret));
		return OMPI_ERROR;
	    }
	    	      
	    if (bytes_read < 0)
	        return OMPI_ERROR;

	    // Copy the data from BUFFER into the memory specified by IOV
	    bytes = bytes_read;
	    for (int i = 0; i < iov_count; ++i) {
	        size_t copy = MIN (iov[i].iov_len, bytes);
		(void) memcpy ((void *) iov[i].iov_base, (void *) buffer, copy);
		buffer += copy;
		bytes -= copy;
		if (bytes == 0) {
		    break;
		}
	    }
	    iov_count = 0;
        }
    }

    else {
        for (i=0 ; i<fh->f_num_of_io_entries ; i++) {
            if (0 == iov_count) {
                iov[iov_count].iov_base = fh->f_io_array[i].memory_address;
                iov[iov_count].iov_len = fh->f_io_array[i].length;
                iov_offset = (OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[i].offset;
                iov_count ++;
            }

            if (OMPIO_IOVEC_INITIAL_SIZE*block <= iov_count) {
                block ++;
                iov = (struct iovec *)realloc
                    (iov, OMPIO_IOVEC_INITIAL_SIZE * block *
		     sizeof(struct iovec));
                if (NULL == iov) {
                    opal_output(1, "OUT OF MEMORY\n");
                    return OMPI_ERR_OUT_OF_RESOURCE;
                }
            }

            if (fh->f_num_of_io_entries != i+1) {
	      if (((OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[i].offset + 
                     (OPAL_PTRDIFF_TYPE)fh->f_io_array[i].length) == 
		  (OMPI_MPI_OFFSET_TYPE)(intptr_t)fh->f_io_array[i+1].offset) {                    
                    iov[iov_count].iov_base = 
                        fh->f_io_array[i+1].memory_address;
                    iov[iov_count].iov_len = fh->f_io_array[i+1].length;
                    iov_count ++;
                    continue;
                }
            }

	    // Find the total number of bytes to be read.
	    size_t bytes = 0;
	    for (int i = 0; i < iov_count; ++i) {
		bytes += iov[i].iov_len;
	    }

	    // Allocate a temporary buffer to hold the data
	    char *buffer;
	    buffer = (char *) malloc (bytes);
	    if (buffer == NULL) {
	        return OMPI_ERROR;
	    }

	    // Read the data
	    ssize_t bytes_read;
	    plfs_ret = plfs_read( pfd, buffer, bytes, iov_offset, &bytes_read );
	    if (PLFS_SUCCESS != plfs_ret) {
	        opal_output(0, "fbtl_plfs_preadv: Error in plfs_read:\n%s\n", strplfserr(plfs_ret));
		return OMPI_ERROR;
	    }

	    if (bytes_read < 0)
	        return OMPI_ERROR;

	    // Copy the data from BUFFER into the memory specified by IOV
	    bytes = bytes_read;
	    for (int i = 0; i < iov_count; ++i) {
	        size_t copy = MIN (iov[i].iov_len, bytes);
		(void) memcpy ((void *) iov[i].iov_base, (void *) buffer, copy);
		buffer += copy;
		bytes -= copy;
		if (bytes == 0) {
		    break;
		}
	    }
	    iov_count = 0;
	}
    }
    if (NULL != iov) {
        free (iov);
        iov = NULL;
    }

    return OMPI_SUCCESS;
}