[svn-r7122] Purpose:

    Code cleanup/Feature removal

Description:
    Remove "round robin" writing of metadata in MPI VFDs (and a couple of other
places).  This never really worked the way I hoped it would and it causes
problems on certain machines.

Platforms tested:
    FreeBSD 4.8 (sleipnir) w/parallel
    Too small for triple check.

8 files changed, 15 insertions, 28 deletions

diff --git a/src/H5Dcontig.c b/src/H5Dcontig.c
index 82ee74a..6445d19 100644
--- a/src/H5Dcontig.c
+++ b/src/H5Dcontig.c
@@ -139,7 +139,6 @@ H5F_contig_fill(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout,
     MPI_Comm	mpi_comm=MPI_COMM_NULL;	/* MPI communicator for file */
     int         mpi_rank=(-1);  /* This process's rank  */
     int         mpi_size=(-1);  /* Total # of processes */
-    int         mpi_round=0;    /* Current process responsible for I/O */
     int         mpi_code;       /* MPI return code */
     unsigned    blocks_written=0; /* Flag to indicate that chunk was actually written */
     unsigned    using_mpi=0;    /* Flag to indicate that the file is being accessed with an MPI-capable file driver */
@@ -266,12 +265,10 @@ H5F_contig_fill(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout,
             /* Check if this file is accessed with an MPI-capable file driver */
             if(using_mpi) {
                 /* Round-robin write the chunks out from only one process */
-                if(mpi_round==mpi_rank) {
+                if(H5_PAR_META_WRITE==mpi_rank) {
                     if (H5F_contig_write(f, (hsize_t)size, addr, size, dxpl_id, buf)<0)
                         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to write fill value to dataset");
                 } /* end if */
-                ++mpi_round;
-                mpi_round %= mpi_size;
 
                 /* Indicate that blocks are being written */
                 blocks_written=1;
diff --git a/src/H5Distore.c b/src/H5Distore.c
index 4847948..acb871d 100644
--- a/src/H5Distore.c
+++ b/src/H5Distore.c
@@ -2159,7 +2159,6 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
     MPI_Comm	mpi_comm=MPI_COMM_NULL;	/* MPI communicator for file */
     int         mpi_rank=(-1);  /* This process's rank  */
     int         mpi_size=(-1);  /* Total # of processes */
-    int         mpi_round=0;    /* Current process responsible for I/O */
     int         mpi_code;       /* MPI return code */
     unsigned    blocks_written=0; /* Flag to indicate that chunk was actually written */
     unsigned    using_mpi=0;    /* Flag to indicate that the file is being accessed with an MPI-capable file driver */
@@ -2355,11 +2354,10 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
                 /* Check if this file is accessed with an MPI-capable file driver */
                 if(using_mpi) {
                     /* Round-robin write the chunks out from only one process */
-                    if(mpi_round==mpi_rank) {
+                    if(H5_PAR_META_WRITE==mpi_rank) {
                         if (H5F_block_write(f, H5FD_MEM_DRAW, udata.addr, udata.key.nbytes, dxpl_id, chunk)<0)
                             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file");
                     } /* end if */
-                    mpi_round = (mpi_round+1)%mpi_size;
 
                     /* Indicate that blocks are being written */
                     blocks_written=1;
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 59e2c83..7a32a2b 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -60,7 +60,6 @@ typedef struct H5FD_mpio_t {
     MPI_Info	info;		/*file information			*/
     int         mpi_rank;       /* This process's rank                  */
     int         mpi_size;       /* Total number of processes            */
-    int         mpi_round;      /* Current round robin process (for metadata I/O) */
     haddr_t	eof;		/*end-of-file marker			*/
     haddr_t	eoa;		/*end-of-address marker			*/
     haddr_t	last_eoa;	/* Last known end-of-address marker	*/
@@ -1883,7 +1882,7 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
 
         /* Only p<round> will do the actual write if all procs in comm write same metadata */
         if (H5_mpi_1_metawrite_g) {
-            if (file->mpi_rank != file->mpi_round) {
+            if (file->mpi_rank != H5_PAR_META_WRITE) {
 #ifdef H5FDmpio_DEBUG
                 if (H5FD_mpio_Debug[(int)'w']) {
                     fprintf(stdout,
@@ -1975,11 +1974,8 @@ done:
     if(ret_value!=FAIL) {
         /* if only p<round> writes, need to broadcast the ret_value to other processes */
         if ((type!=H5FD_MEM_DRAW) && H5_mpi_1_metawrite_g) {
-            if (MPI_SUCCESS != (mpi_code=MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, file->mpi_round, file->comm)))
+            if (MPI_SUCCESS != (mpi_code=MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, H5_PAR_META_WRITE, file->comm)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code);
-
-            /* Round-robin rotate to the next process */
-            file->mpi_round = (file->mpi_round+1)%file->mpi_size;
         } /* end if */
     } /* end if */
 
diff --git a/src/H5FDmpiposix.c b/src/H5FDmpiposix.c
index 65f4ec1..a56a18d 100644
--- a/src/H5FDmpiposix.c
+++ b/src/H5FDmpiposix.c
@@ -83,7 +83,6 @@ typedef struct H5FD_mpiposix_t {
     MPI_Comm	comm;		/*communicator				*/
     int         mpi_rank;       /* This process's rank                  */
     int         mpi_size;       /* Total number of processes            */
-    int         mpi_round;      /* Current round robin process (for metadata I/O) */
     haddr_t	eof;		/*end-of-file marker			*/
     haddr_t	eoa;		/*end-of-address marker			*/
     haddr_t	last_eoa;	/* Last known end-of-address marker	*/
@@ -936,7 +935,6 @@ H5FD_mpiposix_open(const char *name, unsigned flags, hid_t fapl_id,
     file->comm = comm_dup;
     file->mpi_rank = mpi_rank;
     file->mpi_size = mpi_size;
-    file->mpi_round = 0;        /* Start metadata writes with process 0 */
 
     /* Reset the last file I/O operation */
     file->pos = HADDR_UNDEF;
@@ -1422,7 +1420,7 @@ H5FD_mpiposix_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
 
         /* Only p<round> will do the actual write if all procs in comm write same metadata */
         if (H5_mpiposix_1_metawrite_g)
-            if (file->mpi_rank != file->mpi_round)
+            if (file->mpi_rank != H5_PAR_META_WRITE)
                 HGOTO_DONE(SUCCEED) /* skip the actual write */
     } /* end if */
 
@@ -1497,11 +1495,8 @@ done:
     else {
         /* if only p<round> writes, need to broadcast the ret_value to other processes */
         if ((type!=H5FD_MEM_DRAW) && H5_mpiposix_1_metawrite_g) {
-            if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, file->mpi_round, file->comm)))
+            if (MPI_SUCCESS != (mpi_code= MPI_Bcast(&ret_value, sizeof(ret_value), MPI_BYTE, H5_PAR_META_WRITE, file->comm)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code);
-
-            /* Round-robin rotate to the next process */
-            file->mpi_round = (file->mpi_round+1)%file->mpi_size;
         } /* end if */
     } /* end else */
 
@@ -1543,7 +1538,7 @@ H5FD_mpiposix_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing
     /* Extend the file to make sure it's large enough */
     if(file->eoa>file->last_eoa) {
         /* Use the round-robin process to truncate (extend) the file */
-        if(file->mpi_rank == file->mpi_round) {
+        if(file->mpi_rank == H5_PAR_META_WRITE) {
 #ifdef WIN32
             /* Map the posix file handle to a Windows file handle */
             filehandle = _get_osfhandle(fd);
diff --git a/src/H5Fcontig.c b/src/H5Fcontig.c
index 82ee74a..6445d19 100644
--- a/src/H5Fcontig.c
+++ b/src/H5Fcontig.c
@@ -139,7 +139,6 @@ H5F_contig_fill(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout,
     MPI_Comm	mpi_comm=MPI_COMM_NULL;	/* MPI communicator for file */
     int         mpi_rank=(-1);  /* This process's rank  */
     int         mpi_size=(-1);  /* Total # of processes */
-    int         mpi_round=0;    /* Current process responsible for I/O */
     int         mpi_code;       /* MPI return code */
     unsigned    blocks_written=0; /* Flag to indicate that chunk was actually written */
     unsigned    using_mpi=0;    /* Flag to indicate that the file is being accessed with an MPI-capable file driver */
@@ -266,12 +265,10 @@ H5F_contig_fill(H5F_t *f, hid_t dxpl_id, struct H5O_layout_t *layout,
             /* Check if this file is accessed with an MPI-capable file driver */
             if(using_mpi) {
                 /* Round-robin write the chunks out from only one process */
-                if(mpi_round==mpi_rank) {
+                if(H5_PAR_META_WRITE==mpi_rank) {
                     if (H5F_contig_write(f, (hsize_t)size, addr, size, dxpl_id, buf)<0)
                         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to write fill value to dataset");
                 } /* end if */
-                ++mpi_round;
-                mpi_round %= mpi_size;
 
                 /* Indicate that blocks are being written */
                 blocks_written=1;
diff --git a/src/H5Fistore.c b/src/H5Fistore.c
index 4847948..acb871d 100644
--- a/src/H5Fistore.c
+++ b/src/H5Fistore.c
@@ -2159,7 +2159,6 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
     MPI_Comm	mpi_comm=MPI_COMM_NULL;	/* MPI communicator for file */
     int         mpi_rank=(-1);  /* This process's rank  */
     int         mpi_size=(-1);  /* Total # of processes */
-    int         mpi_round=0;    /* Current process responsible for I/O */
     int         mpi_code;       /* MPI return code */
     unsigned    blocks_written=0; /* Flag to indicate that chunk was actually written */
     unsigned    using_mpi=0;    /* Flag to indicate that the file is being accessed with an MPI-capable file driver */
@@ -2355,11 +2354,10 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
                 /* Check if this file is accessed with an MPI-capable file driver */
                 if(using_mpi) {
                     /* Round-robin write the chunks out from only one process */
-                    if(mpi_round==mpi_rank) {
+                    if(H5_PAR_META_WRITE==mpi_rank) {
                         if (H5F_block_write(f, H5FD_MEM_DRAW, udata.addr, udata.key.nbytes, dxpl_id, chunk)<0)
                             HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file");
                     } /* end if */
-                    mpi_round = (mpi_round+1)%mpi_size;
 
                     /* Indicate that blocks are being written */
                     blocks_written=1;
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 78dcf14..5bd2ec3 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -185,6 +185,7 @@ struct H5F_t {
 };
 
 #ifdef H5_HAVE_PARALLEL
+/* Whether a single process writes metadata */
 H5_DLLVAR  hbool_t H5_mpi_1_metawrite_g;
 H5_DLLVAR  hbool_t H5_mpiposix_1_metawrite_g;
 #endif /* H5_HAVE_PARALLEL */
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 53dc8ad..6c81e21 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -368,6 +368,11 @@ typedef struct H5F_t H5F_t;
 #define H5F_MNT_SYM_LOCAL_SIZE		sizeof(hbool_t) 	
 #define H5F_MNT_SYM_LOCAL_DEF	 	FALSE	
 
+#ifdef H5_HAVE_PARALLEL
+/* Which process writes metadata */
+#define H5_PAR_META_WRITE 0
+#endif /* H5_HAVE_PARALLEL */
+
 /* Forward declarations for prototype arguments */
 struct H5B_class_t;
 union H5D_storage_t;