ad_xfs_iwrite.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_xfs_iwrite.c,v 1.6 2002/10/24 17:01:09 gropp Exp $    
 *
 *   Copyright (C) 1997 University of Chicago. 
 *   See COPYRIGHT notice in top-level directory.
 */

#include "ad_xfs.h"

void ADIOI_XFS_IwriteContig(ADIO_File fd, void *buf, int count, 
                MPI_Datatype datatype, int file_ptr_type,
                ADIO_Offset offset, ADIO_Request *request, int *error_code)  
{
    int len, typesize, err=-1;
#ifndef PRINT_ERR_MSG
    static char myname[] = "ADIOI_XFS_IWRITECONTIG";
#endif

    *request = ADIOI_Malloc_request();
    (*request)->optype = ADIOI_WRITE;
    (*request)->fd = fd;
    (*request)->datatype = datatype;

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

    if (file_ptr_type == ADIO_INDIVIDUAL) offset = fd->fp_ind;
    err = ADIOI_XFS_aio(fd, buf, len, offset, 1, &((*request)->handle));
    if (file_ptr_type == ADIO_INDIVIDUAL) fd->fp_ind += len;

    (*request)->queued = 1;
    ADIOI_Add_req_to_list(request);

#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

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



void ADIOI_XFS_IwriteStrided(ADIO_File fd, void *buf, int count, 
		       MPI_Datatype datatype, int file_ptr_type,
                       ADIO_Offset offset, ADIO_Request *request, int
                       *error_code)
{
    ADIO_Status status;
#ifdef HAVE_STATUS_SET_BYTES
    int typesize;
#endif

    *request = ADIOI_Malloc_request();
    (*request)->optype = ADIOI_WRITE;
    (*request)->fd = fd;
    (*request)->datatype = datatype;
    (*request)->queued = 0;
    (*request)->handle = 0;

/* call the blocking version. It is faster because it does data sieving. */
    ADIOI_XFS_WriteStrided(fd, buf, count, datatype, file_ptr_type, 
                            offset, &status, error_code);  

    fd->async_count++;

#ifdef HAVE_STATUS_SET_BYTES
    if (*error_code == MPI_SUCCESS) {
	MPI_Type_size(datatype, &typesize);
	(*request)->nbytes = count * typesize;
    }
#endif
}


/* This function is for implementation convenience. It is not user-visible.
   It takes care of the differences in the interface for nonblocking I/O
   on various Unix machines! If wr==1 write, wr==0 read. */

int ADIOI_XFS_aio(ADIO_File fd, void *buf, int len, ADIO_Offset offset,
		  int wr, void *handle)
{
    int err, error_code;
    aiocb64_t *aiocbp;

    aiocbp = (aiocb64_t *) ADIOI_Calloc(sizeof(aiocb64_t), 1);

    if (((wr && fd->direct_write) || (!wr && fd->direct_read))
	&& !(((long) buf) % fd->d_mem) && !(offset % fd->d_miniosz) && 
	!(len % fd->d_miniosz) && (len >= fd->d_miniosz) && 
	(len <= fd->d_maxiosz))
	aiocbp->aio_fildes = fd->fd_direct;
    else aiocbp->aio_fildes = fd->fd_sys;

    aiocbp->aio_offset = offset;
    aiocbp->aio_buf = buf;
    aiocbp->aio_nbytes = len;
    aiocbp->aio_reqprio = 0;

#ifdef AIO_SIGNOTIFY_NONE
/* SGI IRIX 6 */
    aiocbp->aio_sigevent.sigev_notify = SIGEV_NONE;
#else
    aiocbp->aio_sigevent.sigev_signo = 0;
#endif

    if (wr) err = aio_write64(aiocbp);
    else err = aio_read64(aiocbp);

    if (err == -1) {
	if (errno == EAGAIN) {
        /* exceeded the max. no. of outstanding requests.
	   complete all previous async. requests and try again. */

	    ADIOI_Complete_async(&error_code);
	    if (wr) err = aio_write64(aiocbp);
	    else err = aio_read64(aiocbp);

	    while (err == -1) {
		if (errno == EAGAIN) {
		    /* sleep and try again */
		    sleep(1);
		    if (wr) err = aio_write64(aiocbp);
		    else err = aio_read64(aiocbp);
		}
		else {
		    FPRINTF(stderr, "Unknown errno %d in ADIOI_XFS_aio\n", errno);
		    MPI_Abort(MPI_COMM_WORLD, 1);
		}
	    }
        }
        else {
            FPRINTF(stderr, "Unknown errno %d in ADIOI_XFS_aio\n", errno);
            MPI_Abort(MPI_COMM_WORLD, 1);
        }
    }

    *((aiocb64_t **) handle) = aiocbp;
    return err;
}