ad_pvfs_read.c

MPICH是MPI的重要研究,提供了一系列的接口函数,为并行计算的实现提供了编程环境.

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/* 
 *   $Id: ad_pvfs_read.c,v 1.8 2002/10/24 17:00:58 gropp Exp $    
 *
 *   Copyright (C) 1997 University of Chicago. 
 *   See COPYRIGHT notice in top-level directory.
 */

#include "adio.h"
#include "adio_extern.h"
#include "ad_pvfs.h"

#ifdef HAVE_PVFS_LISTIO
void ADIOI_PVFS_ReadStridedListIO(ADIO_File fd, void *buf, int count,
                       MPI_Datatype datatype, int file_ptr_type,
                       ADIO_Offset offset, ADIO_Status *status, int
                       *error_code);
#endif

void ADIOI_PVFS_ReadContig(ADIO_File fd, void *buf, int count, 
                     MPI_Datatype datatype, int file_ptr_type,
		     ADIO_Offset offset, ADIO_Status *status, int *error_code)
{
    int err=-1, datatype_size, len;
#ifndef PRINT_ERR_MSG
    static char myname[] = "ADIOI_PVFS_READCONTIG";
#endif

    MPI_Type_size(datatype, &datatype_size);
    len = datatype_size * count;

    if (file_ptr_type == ADIO_EXPLICIT_OFFSET) {
	if (fd->fp_sys_posn != offset)
	    pvfs_lseek64(fd->fd_sys, offset, SEEK_SET);
	err = pvfs_read(fd->fd_sys, buf, len);
	fd->fp_sys_posn = offset + err;
	/* individual file pointer not updated */        
    }
    else {  /* read from curr. location of ind. file pointer */
	if (fd->fp_sys_posn != fd->fp_ind)
	    pvfs_lseek64(fd->fd_sys, fd->fp_ind, SEEK_SET);
	err = pvfs_read(fd->fd_sys, buf, len);
	fd->fp_ind += err; 
	fd->fp_sys_posn = fd->fp_ind;
    }         

#ifdef HAVE_STATUS_SET_BYTES
    if (err != -1) MPIR_Status_set_bytes(status, datatype, err);
#endif

#ifdef PRINT_ERR_MSG
    *error_code = (err == -1) ? MPI_ERR_UNKNOWN : MPI_SUCCESS;
#else
    if (err == -1) {
	*error_code = MPIR_Err_setmsg(MPI_ERR_IO, MPIR_ADIO_ERROR,
			      myname, "I/O Error", "%s", strerror(errno));
	ADIOI_Error(fd, *error_code, myname);	    
    }
    else *error_code = MPI_SUCCESS;
#endif
}


void ADIOI_PVFS_ReadStrided(ADIO_File fd, void *buf, int count,
                       MPI_Datatype datatype, int file_ptr_type,
                       ADIO_Offset offset, ADIO_Status *status, int
                       *error_code)
{
#ifdef HAVE_PVFS_LISTIO
    if ( fd->hints->fs_hints.pvfs.listio_read == ADIOI_HINT_ENABLE) {
	    ADIOI_PVFS_ReadStridedListIO(fd, buf, count, datatype, file_ptr_type,
			    offset, status, error_code);
	    return;
    }
#endif
/* If hint set to DISABLE or AUTOMATIC, don't use listio */
    ADIOI_GEN_ReadStrided(fd, buf, count, datatype, file_ptr_type,
		    offset, status, error_code);
}

#ifdef HAVE_PVFS_LISTIO
void ADIOI_PVFS_ReadStridedListIO(ADIO_File fd, void *buf, int count,
                       MPI_Datatype datatype, int file_ptr_type,
                       ADIO_Offset offset, ADIO_Status *status, int
                       *error_code)
{
/* offset is in units of etype relative to the filetype. */

    ADIOI_Flatlist_node *flat_buf, *flat_file;
    int i, j, k, l, brd_size, frd_size=0, st_index=0;
    int bufsize, sum, n_etypes_in_filetype, size_in_filetype;
    int n_filetypes, etype_in_filetype;
    ADIO_Offset abs_off_in_filetype=0;
    int filetype_size, etype_size, buftype_size;
    MPI_Aint filetype_extent, buftype_extent; 
    int buf_count, buftype_is_contig, filetype_is_contig;
    ADIO_Offset userbuf_off;
    ADIO_Offset off, disp, start_off;
    int flag, st_frd_size, st_n_filetypes;
    int new_brd_size, new_frd_size;

    int mem_list_count, file_list_count;
    char **mem_offsets;
    int64_t *file_offsets;
    int *mem_lengths;
    int32_t *file_lengths;
    int total_blks_to_read;

    int max_mem_list, max_file_list;

    int b_blks_read;
    int f_data_read;
    int size_read=0, n_read_lists, extra_blks;

    int end_brd_size, end_frd_size;
    int start_k, start_j, new_file_read, new_buffer_read;
    int start_mem_offset;

#define MAX_ARRAY_SIZE 11

#ifndef PRINT_ERR_MESG
  static char myname[] = "ADIOI_PVFS_ReadStrided";
#endif

    *error_code = MPI_SUCCESS;  /* changed below if error */

    ADIOI_Datatype_iscontig(datatype, &buftype_is_contig);
    ADIOI_Datatype_iscontig(fd->filetype, &filetype_is_contig);
    MPI_Type_size(fd->filetype, &filetype_size);
    if ( ! filetype_size ) {
	*error_code = MPI_SUCCESS; 
	return;
    }

    MPI_Type_extent(fd->filetype, &filetype_extent);
    MPI_Type_size(datatype, &buftype_size);
    MPI_Type_extent(datatype, &buftype_extent);
    etype_size = fd->etype_size;

    bufsize = buftype_size * count;

    if (!buftype_is_contig && filetype_is_contig) {

/* noncontiguous in memory, contiguous in file. */
        int64_t file_offsets;
	int32_t file_lengths;

	ADIOI_Flatten_datatype(datatype);
	flat_buf = ADIOI_Flatlist;
	while (flat_buf->type != datatype) flat_buf = flat_buf->next;

	off = (file_ptr_type == ADIO_INDIVIDUAL) ? fd->fp_ind : 
	    fd->disp + etype_size * offset;

	file_list_count = 1;
	file_offsets = off;
	file_lengths = 0;
	total_blks_to_read = count*flat_buf->count;
	b_blks_read = 0;

	/* allocate arrays according to max usage */
	if (total_blks_to_read > MAX_ARRAY_SIZE)
	    mem_list_count = MAX_ARRAY_SIZE;
	else mem_list_count = total_blks_to_read;
	mem_offsets = (char**)ADIOI_Malloc(mem_list_count*sizeof(char*));
	mem_lengths = (int*)ADIOI_Malloc(mem_list_count*sizeof(int));

	j = 0;
	/* step through each block in memory, filling memory arrays */
	while (b_blks_read < total_blks_to_read) {
	    for (i=0; i<flat_buf->count; i++) {
		mem_offsets[b_blks_read % MAX_ARRAY_SIZE] = 
		    (char*)((char *)buf + j*buftype_extent + flat_buf->indices[i]);
		mem_lengths[b_blks_read % MAX_ARRAY_SIZE] = 
		    flat_buf->blocklens[i];
		file_lengths += flat_buf->blocklens[i];
		b_blks_read++;
		if (!(b_blks_read % MAX_ARRAY_SIZE) ||
		    (b_blks_read == total_blks_to_read)) {

		    /* in the case of the last read list call,
		       adjust mem_list_count */
		    if (b_blks_read == total_blks_to_read) {
		        mem_list_count = total_blks_to_read % MAX_ARRAY_SIZE;
			/* in case last read list call fills max arrays */
			if (!mem_list_count) mem_list_count = MAX_ARRAY_SIZE;
		    }

		    pvfs_read_list(fd->fd_sys ,mem_list_count, mem_offsets,
				   mem_lengths, file_list_count,
				   &file_offsets, &file_lengths);
		  
		    /* in the case of the last read list call, leave here */
		    if (b_blks_read == total_blks_to_read) break;

		    file_offsets += file_lengths;
		    file_lengths = 0;
		} 
	    } /* for (i=0; i<flat_buf->count; i++) */
	    j++;
	} /* while (b_blks_read < total_blks_to_read) */
	ADIOI_Free(mem_offsets);
	ADIOI_Free(mem_lengths);

        if (file_ptr_type == ADIO_INDIVIDUAL) fd->fp_ind = off;

	fd->fp_sys_posn = -1;  /* set it to null. */

#ifdef HAVE_STATUS_SET_BYTES
	MPIR_Status_set_bytes(status, datatype, bufsize);
	/* This isa temporary way of filling in status.  The right way is to
	   keep tracke of how much data was actually read adn placed in buf
	   by ADIOI_BUFFERED_READ. */
#endif
	ADIOI_Delete_flattened(datatype);

	return;
    } /* if (!buftype_is_contig && filetype_is_contig) */

    /* know file is noncontiguous from above */
    /* noncontiguous in file */

    /* filetype already flattened in ADIO_Open */
    flat_file = ADIOI_Flatlist;
    while (flat_file->type != fd->filetype) flat_file = flat_file->next;

    disp = fd->disp;

    /* for each case - ADIO_Individual pointer or explicit, find the file
       offset in bytes (offset), n_filetypes (how many filetypes into
       file to start), frd_size (remaining amount of data in present
       file block), and st_index (start point in terms of blocks in
       starting filetype) */
    if (file_ptr_type == ADIO_INDIVIDUAL) {
        offset = fd->fp_ind; /* in bytes */
	n_filetypes = -1;
	flag = 0;
	while (!flag) {
	    n_filetypes++;
	    for (i=0; i<flat_file->count; i++) {
	        if (disp + flat_file->indices[i] + 
		    (ADIO_Offset) n_filetypes*filetype_extent +
		    flat_file->blocklens[i]  >= offset) {
		    st_index = i;
		    frd_size = (int) (disp + flat_file->indices[i] + 
				      (ADIO_Offset) n_filetypes*filetype_extent
				      + flat_file->blocklens[i] - offset);
		    flag = 1;
		    break;
		}
	    }
	} /* while (!flag) */
    } /* if (file_ptr_type == ADIOI_INDIVIDUAL) */
    else {
        n_etypes_in_filetype = filetype_size/etype_size;
	n_filetypes = (int) (offset / n_etypes_in_filetype);
	etype_in_filetype = (int) (offset % n_etypes_in_filetype);
	size_in_filetype = etype_in_filetype * etype_size;
	
	sum = 0;
	for (i=0; i<flat_file->count; i++) {
	    sum += flat_file->blocklens[i];
	    if (sum > size_in_filetype) {
	        st_index = i;
		frd_size = sum - size_in_filetype;
		abs_off_in_filetype = flat_file->indices[i] +
		    size_in_filetype - (sum - flat_file->blocklens[i]);
		break;
	    }
	}
	
	/* abs. offset in bytes in the file */
	offset = disp + (ADIO_Offset) n_filetypes*filetype_extent + 
	    abs_off_in_filetype;
    } /* else [file_ptr_type != ADIOI_INDIVIDUAL] */

    start_off = offset;
    st_frd_size = frd_size;
    st_n_filetypes = n_filetypes;
    
    if (buftype_is_contig && !filetype_is_contig) {

/* contiguous in memory, noncontiguous in file. should be the most
   common case. */

        int mem_lengths;
	char *mem_offsets;
	
	i = 0;
	j = st_index;
	n_filetypes = st_n_filetypes;
	
	mem_list_count = 1;
	
	/* determine how many blocks in file to read */
	f_data_read = ADIOI_MIN(st_frd_size, bufsize);
	total_blks_to_read = 1;
	j++;
	while (f_data_read < bufsize) {
	    f_data_read += flat_file->blocklens[j];
	    total_blks_to_read++;
	    if (j<(flat_file->count-1)) j++;
	    else j = 0;	
	}
      
	j = st_index;
	n_filetypes = st_n_filetypes;
	n_read_lists = total_blks_to_read/MAX_ARRAY_SIZE;
	extra_blks = total_blks_to_read%MAX_ARRAY_SIZE;
	
	mem_offsets = buf;
	mem_lengths = 0;
	
	/* if at least one full readlist, allocate file arrays
	   at max array size and don't free until very end */
	if (n_read_lists) {
	    file_offsets = (int64_t*)ADIOI_Malloc(MAX_ARRAY_SIZE*
						  sizeof(int64_t));
	    file_lengths = (int32_t*)ADIOI_Malloc(MAX_ARRAY_SIZE*
						  sizeof(int32_t));
	}
	/* if there's no full readlist allocate file arrays according
	   to needed size (extra_blks) */
	else {
	    file_offsets = (int64_t*)ADIOI_Malloc(extra_blks*
						  sizeof(int64_t));
	    file_lengths = (int32_t*)ADIOI_Malloc(extra_blks*
						  sizeof(int32_t));
	}
	
	/* for file arrays that are of MAX_ARRAY_SIZE, build arrays */
	for (i=0; i<n_read_lists; i++) {
	    file_list_count = MAX_ARRAY_SIZE;
	    if(!i) {
	        file_offsets[0] = offset;
		file_lengths[0] = st_frd_size;
		mem_lengths = st_frd_size;
	    }
	    for (k=0; k<MAX_ARRAY_SIZE; k++) {
	        if (i || k) {
		    file_offsets[k] = disp + n_filetypes*filetype_extent
		      + flat_file->indices[j];
		    file_lengths[k] = flat_file->blocklens[j];
		    mem_lengths += file_lengths[k];
		}
		if (j<(flat_file->count - 1)) j++;
		else {
		    j = 0;
		    n_filetypes++;
		}
	    } /* for (k=0; k<MAX_ARRAY_SIZE; k++) */
	    pvfs_read_list(fd->fd_sys, mem_list_count,
			   &mem_offsets, &mem_lengths,
			   file_list_count, file_offsets,
			   file_lengths);
	    mem_offsets += mem_lengths;
	    mem_lengths = 0;
	} /* for (i=0; i<n_read_lists; i++) */

	/* for file arrays smaller than MAX_ARRAY_SIZE (last read_list call) */
	if (extra_blks) {
	    file_list_count = extra_blks;
	    if(!i) {
	        file_offsets[0] = offset;
		file_lengths[0] = st_frd_size;
	    }
	    for (k=0; k<extra_blks; k++) {
	        if(i || k) {
		    file_offsets[k] = disp + n_filetypes*filetype_extent +
		      flat_file->indices[j];
		    if (k == (extra_blks - 1)) {
		        file_lengths[k] = bufsize - (int32_t) mem_lengths
			  - (int32_t) mem_offsets + (int32_t)  buf;
		    }
		    else file_lengths[k] = flat_file->blocklens[j];
		} /* if(i || k) */
		mem_lengths += file_lengths[k];
		if (j<(flat_file->count - 1)) j++;
		else {
		    j = 0;
		    n_filetypes++;
		}
	    } /* for (k=0; k<extra_blks; k++) */