ad_nfs_read.c

fortran并行计算包

        if (fd->atomicity)
            ADIOI_UNLOCK(fd, start_off, SEEK_SET, end_offset-start_off+1);

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

	ADIOI_Free(readbuf); /* malloced in the buffered_read macro */

	if (err_flag) {
	    *error_code = MPIO_Err_create_code(MPI_SUCCESS,
					       MPIR_ERR_RECOVERABLE, myname,
					       __LINE__, MPI_ERR_IO, "**io",
					       "**io %s", strerror(errno));
	}
	else *error_code = MPI_SUCCESS;
    }

    else {  /* 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;

	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;
		    }
		}
	    }
	}
	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;
	}

        start_off = offset;

       /* Calculate end_offset, the last byte-offset that will be accessed.
         e.g., if start_offset=0 and 100 bytes to be read, end_offset=99*/

	st_frd_size = frd_size;
	st_n_filetypes = n_filetypes;
	i = 0;
	j = st_index;
	off = offset;
	frd_size = ADIOI_MIN(st_frd_size, bufsize);
	while (i < bufsize) {
	    i += frd_size;
	    end_offset = off + frd_size - 1;

	    if (j < (flat_file->count - 1)) j++;
	    else {
		j = 0;
		n_filetypes++;
	    }

	    off = disp + flat_file->indices[j] + (ADIO_Offset) n_filetypes*filetype_extent;
	    frd_size = ADIOI_MIN(flat_file->blocklens[j], bufsize-i);
	}

/* if atomicity is true, lock (exclusive) the region to be accessed */
        if (fd->atomicity)
            ADIOI_WRITE_LOCK(fd, start_off, SEEK_SET, end_offset-start_off+1);

        /* initial read into readbuf */
	readbuf_off = offset;
	readbuf = (char *) ADIOI_Malloc(max_bufsize);
	readbuf_len = (int) (ADIOI_MIN(max_bufsize, end_offset-readbuf_off+1));

#ifdef ADIOI_MPE_LOGGING
        MPE_Log_event( ADIOI_MPE_lseek_a, 0, NULL );
#endif
	lseek(fd->fd_sys, offset, SEEK_SET);
#ifdef ADIOI_MPE_LOGGING
        MPE_Log_event( ADIOI_MPE_lseek_b, 0, NULL );
#endif
        if (!(fd->atomicity)) ADIOI_READ_LOCK(fd, offset, SEEK_SET, readbuf_len);
#ifdef ADIOI_MPE_LOGGING
        MPE_Log_event( ADIOI_MPE_read_a, 0, NULL );
#endif
        err = read(fd->fd_sys, readbuf, readbuf_len);
#ifdef ADIOI_MPE_LOGGING
        MPE_Log_event( ADIOI_MPE_read_b, 0, NULL );
#endif
        if (!(fd->atomicity)) ADIOI_UNLOCK(fd, offset, SEEK_SET, readbuf_len);

        if (err == -1) err_flag = 1;

	if (buftype_is_contig && !filetype_is_contig) {

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

	    i = 0;
	    j = st_index;
	    off = offset;
	    n_filetypes = st_n_filetypes;
	    frd_size = ADIOI_MIN(st_frd_size, bufsize);
	    while (i < bufsize) {
                if (frd_size) { 
                    /* TYPE_UB and TYPE_LB can result in 
                       frd_size = 0. save system call in such cases */ 
		    /* lseek(fd->fd_sys, off, SEEK_SET);
		    err = read(fd->fd_sys, ((char *) buf) + i, frd_size);*/

		    req_off = off;
		    req_len = frd_size;
		    userbuf_off = i;
		    ADIOI_BUFFERED_READ
		}
		i += frd_size;

                if (off + frd_size < disp + flat_file->indices[j] +
                   flat_file->blocklens[j] + (ADIO_Offset) n_filetypes*filetype_extent)
                       off += frd_size;
                /* did not reach end of contiguous block in filetype.
                   no more I/O needed. off is incremented by frd_size. */
                else {
		    if (j < (flat_file->count - 1)) j++;
		    else {
			j = 0;
			n_filetypes++;
		    }
		    off = disp + flat_file->indices[j] + 
                                        (ADIO_Offset) n_filetypes*filetype_extent;
		    frd_size = ADIOI_MIN(flat_file->blocklens[j], bufsize-i);
		}
	    }
	}
	else {
/* noncontiguous in memory as well as in file */

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

	    k = num = buf_count = 0;
	    i = (int) (flat_buf->indices[0]);
	    j = st_index;
	    off = offset;
	    n_filetypes = st_n_filetypes;
	    frd_size = st_frd_size;
	    brd_size = flat_buf->blocklens[0];

	    while (num < bufsize) {
		size = ADIOI_MIN(frd_size, brd_size);
		if (size) {
		    /* lseek(fd->fd_sys, off, SEEK_SET);
		    err = read(fd->fd_sys, ((char *) buf) + i, size); */

		    req_off = off;
		    req_len = size;
		    userbuf_off = i;
		    ADIOI_BUFFERED_READ
		}

		new_frd_size = frd_size;
		new_brd_size = brd_size;

		if (size == frd_size) {
/* reached end of contiguous block in file */
		    if (j < (flat_file->count - 1)) j++;
		    else {
			j = 0;
			n_filetypes++;
		    }

		    off = disp + flat_file->indices[j] + 
                                              (ADIO_Offset) n_filetypes*filetype_extent;

		    new_frd_size = flat_file->blocklens[j];
		    if (size != brd_size) {
			i += size;
			new_brd_size -= size;
		    }
		}

		if (size == brd_size) {
/* reached end of contiguous block in memory */

		    k = (k + 1)%flat_buf->count;
		    buf_count++;
		    i = (int) (buftype_extent*(buf_count/flat_buf->count) +
			flat_buf->indices[k]); 
		    new_brd_size = flat_buf->blocklens[k];
		    if (size != frd_size) {
			off += size;
			new_frd_size -= size;
		    }
		}
		num += size;
		frd_size = new_frd_size;
                brd_size = new_brd_size;
	    }
	}
	
        if (fd->atomicity)
            ADIOI_UNLOCK(fd, start_off, SEEK_SET, end_offset-start_off+1);

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

	ADIOI_Free(readbuf); /* malloced in the buffered_read macro */

	if (err_flag) {
	    *error_code = MPIO_Err_create_code(MPI_SUCCESS,
					       MPIR_ERR_RECOVERABLE, myname,
					       __LINE__, MPI_ERR_IO, "**io",
					       "**io %s", strerror(errno));
	}
	else *error_code = MPI_SUCCESS;
    }

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

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

    if (!buftype_is_contig) ADIOI_Delete_flattened(datatype);
}