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authorMuQun Yang <ymuqun@hdfgroup.org>2006-03-20 17:13:36 (GMT)
committerMuQun Yang <ymuqun@hdfgroup.org>2006-03-20 17:13:36 (GMT)
commitebc9e3981b73686ef95ac7cf3660c89a4d5d8faa (patch)
tree32b16eaa71bf29134c376e2dd715a68ea91bc623 /src
parenta53790e16a5e7109a52e8b4a611954f52890a804 (diff)
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[svn-r12123] Purpose:
Add more comments Description: Add more comments to H5Dmpio.c, which describes a little bit more about collective IO management. Solution: Platforms tested: Only test at heping since only comments were added. Misc. update:
Diffstat (limited to 'src')
-rw-r--r--src/H5Dmpio.c26
1 files changed, 14 insertions, 12 deletions
diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index d6c135f..4d0111b 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -279,6 +279,12 @@ done:
/*-------------------------------------------------------------------------
* Function: H5D_mpio_chunk_adjust_iomode
*
+ * Decription: If H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS is not defined,
+ collective IO with no contribution from one or more
+ processes are not assured. We will check the minimum
+ number of chunks the process is used. If the number is
+ zero, we will use independent IO mode instead.
+ This is necessary with Linked chunk IO.
* Purpose: Checks if it is possible to do collective IO
*
* Return: Success: Non-negative: TRUE or FALSE
@@ -557,10 +563,8 @@ done:
/*-------------------------------------------------------------------------
* Function: H5D_contig_collective_io
*
- * Purpose: Routine for
- * 1) building up MPI derived datatype
- * 2) setting up collective IO property list
- * 3) Do IO
+ * Purpose: Wrapper Routine for H5D_inter_collective_io
+ The starting address of contiguous storage is passed
*
*
* Return: Non-negative on success/Negative on failure
@@ -653,9 +657,12 @@ H5D_chunk_collective_io(H5D_io_info_t *io_info,fm_map *fm,const void *buf, hbool
/* Obtain the data transfer properties */
if(NULL == (plist = H5I_object(io_info->dxpl_id)))
HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")
+
+ /* Check the optional property list on what to do with collective chunk IO. */
chunk_opt_mode=(H5FD_mpio_chunk_opt_t)H5P_peek_unsigned(plist,H5D_XFER_MPIO_CHUNK_OPT_HARD_NAME);
- if(chunk_opt_mode == H5FD_MPIO_OPT_ONE_IO) io_option = H5D_ONE_LINK_CHUNK_IO;
- else if(chunk_opt_mode == H5FD_MPIO_OPT_MULTI_IO) io_option = H5D_MULTI_CHUNK_IO;
+
+ if(chunk_opt_mode == H5FD_MPIO_OPT_ONE_IO) io_option = H5D_ONE_LINK_CHUNK_IO;/*no opt*/
+ else if(chunk_opt_mode == H5FD_MPIO_OPT_MULTI_IO) io_option = H5D_MULTI_CHUNK_IO;/*no opt */
else {
if(H5D_mpio_get_sum_chunk(io_info,fm,&sum_chunk)<0)
HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSWAP, FAIL, "unable to obtain the total chunk number of all processes");
@@ -879,7 +886,7 @@ printf("before inter_collective_io for total chunk = 1 \n");
/* Sort the chunk address
when chunk optimization selection is either H5D_OBTAIN_*/
- if(num_chunk == 0){
+ if(num_chunk == 0){ /* special case: this process doesn't select anything */
if(H5D_istore_chunkmap(io_info,total_chunks,total_chunk_addr_array,fm->down_chunks)<0)
HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get chunk address");
chunk_base_addr = total_chunk_addr_array[0];
@@ -906,7 +913,6 @@ printf("before inter_collective_io for total chunk = 1 \n");
/* Chunk address relative to the first chunk */
chunk_addr_info_array[i].chunk_addr -= chunk_base_addr;
H5_ASSIGN_OVERFLOW(chunk_disp_array[i],chunk_addr_info_array[i].chunk_addr,haddr_t,MPI_Aint);
- /*chunk_disp_array[i] = (MPI_Aint)chunk_addr_array[i];*/
}
blocklen_value = 1;
@@ -1034,8 +1040,6 @@ H5D_multi_chunk_collective_io(H5D_io_info_t *io_info,fm_map *fm,const void *buf,
printf("total_chunk %d\n",total_chunk);
#endif
-
-
/* obtain IO option for each chunk */
if(H5D_obtain_mpio_mode(io_info,fm,chunk_io_option,chunk_addr)<0)
HGOTO_ERROR (H5E_DATASET, H5E_CANTRECV, FAIL, "unable to obtain MPIO mode");
@@ -1105,8 +1109,6 @@ printf("inside collective chunk IO mpi_rank = %d, chunk index = %d\n",mpi_rank,i
HGOTO_ERROR(H5E_IO, H5E_CANTGET, FAIL,"couldn't finish shared collective MPI-IO");
}
-
-
last_io_mode_coll = TRUE;
}