[svn-r21101] HDFFV-7639

Purpose:

    Remove H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS and
    H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS #defines from source.

Description:

    Two advanced parallel functionalities, special collective IO and
    complex derived datatypes, are not supported by older
    implementations of mpi, and thus our code limits the use of these
    features with #ifdefs and has checks in configure to set them (or
    not). Unfortunately, configure can't actually run a parallel check
    to see if these features are working (nor not) so it resorts to
    looking in the config files where they are explicity enabled or
    disabled based on versions of mpi, sytems being built on, or for
    no documented reason at all (i.e. just set to on or off as some
    'default'). Overriding these settings is easy if need be, provided
    it is known that it needs to be done to get improved performance,
    and oftentimes it is not.

    Most new MPI implementations successfully handle the functionality
    requested when these #defines are set, and many of the "turn these
    features off" cases in the config files are for old (> 5 years)
    versions of MPI and retired systems (such as NCSA's tungsten).

    Therefore, the decision has been made to remove the support for
    these old versions of MPI and systems that cannot handle these
    behaviors. The #ifdefs and supporting setup in the config/ files
    and configure script has been removed, and the code executed when
    these options were not set removed from the source.

    In passing, this commit also cleans up some whitespace issues in
    both t_mpi.c and H5Dmpio.c. Furthermore, in t_mpi.c, the special
    collective IO test was not getting regularly run due to it being
    written to work only with four processes (we regularly test with
    six, previously with three), and thus it failed when actually run
    due to an out of bounds data buffer assignment. It has been
    modified to run at any number of processes greater than four, and
    the memory problem has been fixed so the test passes.

Tested:

    jam, h5committest, ember

1 files changed, 135 insertions, 342 deletions

diff --git a/src/H5Dmpio.c b/src/H5Dmpio.c
index e646a7b..1c69305 100644
--- a/src/H5Dmpio.c
+++ b/src/H5Dmpio.c
@@ -17,33 +17,33 @@
  * Programmer:  rky 980813
  * KY 2005 revised the code and made the change to support and optimize
  * collective IO support.
- * Purpose:	Functions to read/write directly between app buffer and file.
+ * Purpose:    Functions to read/write directly between app buffer and file.
  *
- * 		Beware of the ifdef'ed print statements.
- *		I didn't make them portable.
+ *         Beware of the ifdef'ed print statements.
+ *         I didn't make them portable.
  */
 
 /****************/
 /* Module Setup */
 /****************/
 
-#define H5D_PACKAGE		/*suppress error about including H5Dpkg	  */
+#define H5D_PACKAGE /* suppress error about including H5Dpkg */
 
 
 /***********/
 /* Headers */
 /***********/
-#include "H5private.h"		/* Generic Functions			*/
-#include "H5Dpkg.h"		/* Datasets				*/
-#include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5Fprivate.h"		/* File access				*/
-#include "H5FDprivate.h"	/* File drivers				*/
-#include "H5Iprivate.h"		/* IDs			  		*/
-#include "H5MMprivate.h"	/* Memory management			*/
-#include "H5Oprivate.h"		/* Object headers		  	*/
-#include "H5Pprivate.h"         /* Property lists                       */
-#include "H5Sprivate.h"		/* Dataspaces 				*/
-#include "H5Vprivate.h"         /* Vector                               */
+#include "H5private.h"        /* Generic Functions */
+#include "H5Dpkg.h"           /* Datasets          */
+#include "H5Eprivate.h"       /* Error handling    */
+#include "H5Fprivate.h"       /* File access       */
+#include "H5FDprivate.h"      /* File drivers      */
+#include "H5Iprivate.h"       /* IDs               */
+#include "H5MMprivate.h"      /* Memory management */
+#include "H5Oprivate.h"       /* Object headers    */
+#include "H5Pprivate.h"       /* Property lists    */
+#include "H5Sprivate.h"       /* Dataspaces        */
+#include "H5Vprivate.h"       /* Vector            */
 
 #ifdef H5_HAVE_PARALLEL
 
@@ -107,20 +107,16 @@ static herr_t H5D_multi_chunk_collective_io(H5D_io_info_t *io_info,
     H5P_genplist_t *dx_plist);
 static herr_t H5D_multi_chunk_collective_io_no_opt(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, H5D_chunk_map_t *fm, H5P_genplist_t *dx_plist);
-#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
 static herr_t H5D_link_chunk_collective_io(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, H5D_chunk_map_t *fm, int sum_chunk);
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
 static herr_t H5D_inter_collective_io(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, const H5S_t *file_space,
     const H5S_t *mem_space);
 static herr_t H5D_final_collective_io(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, hsize_t nelmts, MPI_Datatype *mpi_file_type,
     MPI_Datatype *mpi_buf_type);
-#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
 static herr_t H5D_sort_chunk(H5D_io_info_t *io_info, const H5D_chunk_map_t *fm,
     H5D_chunk_addr_info_t chunk_addr_info_array[], int many_chunk_opt);
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
 static herr_t H5D_obtain_mpio_mode(H5D_io_info_t *io_info, H5D_chunk_map_t *fm,
     H5P_genplist_t *dx_plist, uint8_t assign_io_mode[], haddr_t chunk_addr[]);
 static herr_t H5D_ioinfo_xfer_mode(H5D_io_info_t *io_info, H5P_genplist_t *dx_plist,
@@ -145,15 +141,15 @@ static herr_t H5D_mpio_get_sum_chunk(const H5D_io_info_t *io_info,
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_mpio_opt_possible
+ * Function:    H5D_mpio_opt_possible
  *
- * Purpose:	Checks if an direct I/O transfer is possible between memory and
+ * Purpose:     Checks if an direct I/O transfer is possible between memory and
  *                  the file.
  *
- * Return:	Success:        Non-negative: TRUE or FALSE
- *		Failure:	Negative
+ * Return:      Sauccess:   Non-negative: TRUE or FALSE
+ *              Failure:    Negative
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Wednesday, April 3, 2002
  *
  *-------------------------------------------------------------------------
@@ -225,19 +221,8 @@ H5D_mpio_opt_possible(const H5D_io_info_t *io_info, const H5S_t *file_space,
      *  storage.  For contiguous storage, mem_space and file_space won't change
      *  when it it is doing disk IO.  For chunking storage, mem_space will
      *  change for different chunks. So for chunking storage, whether we can
-     *  use collective IO will defer until each chunk IO is reached.  For
-     *  contiguous storage, if we find MPI-IO cannot support complicated MPI
-     *  derived data type and the shape of data space is not regular, we will
-     *  set use_par_opt_io = FALSE.
+     *  use collective IO will defer until each chunk IO is reached.
      */
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-    if(io_info->dset->shared->layout.type == H5D_CONTIGUOUS)
-        if((H5S_SELECT_IS_REGULAR(file_space) != TRUE) ||
-                (H5S_SELECT_IS_REGULAR(mem_space) != TRUE)) {
-            local_opinion = FALSE;
-            goto broadcast;
-        } /* end if */
-#endif
 
     /* Don't allow collective operations if filters need to be applied */
     if(io_info->dset->shared->layout.type == H5D_CHUNKED) {
@@ -245,24 +230,6 @@ H5D_mpio_opt_possible(const H5D_io_info_t *io_info, const H5S_t *file_space,
             local_opinion = FALSE;
             goto broadcast;
         } /* end if */
-
-/* If H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS and H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
- *      are defined, the HDF5 library will do collective IO if the application
- *      asks for it.
- *
- * If H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS is not defined and one or more
- *      processes are not participating in the IO, then collective IO is not
- *      assured. The library will check each process for the number of chunks
- *      it involves. If any process involves zero chunks, the library will use
- *      independent IO mode instead.
- */
-#ifndef H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS
-        /* Check the number of chunks to perform I/O on */
-        if(0 == H5SL_count(fm->sel_chunks)) {
-            local_opinion = FALSE;
-            goto broadcast;
-         } /* end if */
-#endif /* H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS */
     } /* end if */
 
 broadcast:
@@ -280,11 +247,11 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_mpio_select_read
+ * Function:    H5D_mpio_select_read
  *
- * Purpose:	MPI-IO function to read directly from app buffer to file.
+ * Purpose:     MPI-IO function to read directly from app buffer to file.
  *
- * Return:	non-negative on success, negative on failure.
+ * Return:      non-negative on success, negative on failure.
  *
  * Programmer:
  *
@@ -301,7 +268,7 @@ H5D_mpio_select_read(const H5D_io_info_t *io_info, const H5D_type_info_t UNUSED
 
     H5_CHECK_OVERFLOW(mpi_buf_count, hsize_t, size_t);
     if(H5F_block_read(io_info->dset->oloc.file, H5FD_MEM_DRAW, store_contig->dset_addr, (size_t)mpi_buf_count, io_info->dxpl_id, io_info->u.rbuf) < 0)
-	HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "can't finish collective parallel read")
+        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "can't finish collective parallel read")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -309,11 +276,11 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_mpio_select_write
+ * Function:    H5D_mpio_select_write
  *
- * Purpose:	MPI-IO function to write directly from app buffer to file.
+ * Purpose:     MPI-IO function to write directly from app buffer to file.
  *
- * Return:	non-negative on success, negative on failure.
+ * Return:      non-negative on success, negative on failure.
  *
  * Programmer:
  *
@@ -339,14 +306,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_ioinfo_xfer_mode
+ * Function:    H5D_ioinfo_xfer_mode
  *
- * Purpose:	Switch to between collective & independent MPI I/O
+ * Purpose:     Switch to between collective & independent MPI I/O
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		Friday, August 12, 2005
+ * Programmer:  Quincey Koziol
+ *              Friday, August 12, 2005
  *
  *-------------------------------------------------------------------------
  */
@@ -354,7 +321,7 @@ static herr_t
 H5D_ioinfo_xfer_mode(H5D_io_info_t *io_info, H5P_genplist_t *dx_plist,
     H5FD_mpio_xfer_t xfer_mode)
 {
-    herr_t	ret_value = SUCCEED;	/*return value		*/
+    herr_t  ret_value = SUCCEED;    /* return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_ioinfo_xfer_mode)
 
@@ -383,15 +350,15 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_ioinfo_coll_opt_mode
+ * Function:    H5D_ioinfo_coll_opt_mode
  *
- * Purpose:	Switch between using collective & independent MPI I/O w/file
+ * Purpose:     Switch between using collective & independent MPI I/O w/file
  *              set view
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	MuQun Yang
- *		Oct. 5th, 2006
+ * Programmer:  MuQun Yang
+ *              Oct. 5th, 2006
  *
  *-------------------------------------------------------------------------
  */
@@ -399,7 +366,7 @@ static herr_t
 H5D_ioinfo_coll_opt_mode(H5D_io_info_t *io_info, H5P_genplist_t *dx_plist,
     H5FD_mpio_collective_opt_t coll_opt_mode)
 {
-    herr_t	ret_value = SUCCEED;	/*return value		*/
+    herr_t  ret_value = SUCCEED;    /* return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_ioinfo_coll_opt_mode)
 
@@ -414,14 +381,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_mpio_get_min_chunk
+ * Function:    H5D_mpio_get_min_chunk
  *
- * Purpose:	Routine for obtaining minimum number of chunks to cover
+ * Purpose:     Routine for obtaining minimum number of chunks to cover
  *              hyperslab selection selected by all processors.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -449,14 +416,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_mpio_get_sum_chunk
+ * Function:    H5D_mpio_get_sum_chunk
  *
- * Purpose:	Routine for obtaining total number of chunks to cover
+ * Purpose:     Routine for obtaining total number of chunks to cover
  *              hyperslab selection selected by all processors.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -487,14 +454,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_contig_collective_read
+ * Function:    H5D_contig_collective_read
  *
- * Purpose:	Reads directly from contiguous data in file into application
+ * Purpose:     Reads directly from contiguous data in file into application
  *              memory using collective I/O.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Tuesday, March  4, 2008
  *
  *-------------------------------------------------------------------------
@@ -514,7 +481,7 @@ H5D_contig_collective_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_i
 
     /* Call generic internal collective I/O routine */
     if(H5D_inter_collective_io(io_info, type_info, file_space, mem_space) < 0)
-	HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "couldn't finish shared collective MPI-IO")
+        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "couldn't finish shared collective MPI-IO")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -522,14 +489,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_contig_collective_write
+ * Function:    H5D_contig_collective_write
  *
- * Purpose:	Write directly to contiguous data in file from application
+ * Purpose:     Write directly to contiguous data in file from application
  *              memory using collective I/O.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Tuesday, March  4, 2008
  *
  *-------------------------------------------------------------------------
@@ -549,7 +516,7 @@ H5D_contig_collective_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_
 
     /* Call generic internal collective I/O routine */
     if(H5D_inter_collective_io(io_info, type_info, file_space, mem_space) < 0)
-	HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "couldn't finish shared collective MPI-IO")
+        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "couldn't finish shared collective MPI-IO")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -557,9 +524,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_chunk_collective_io
+ * Function:    H5D_chunk_collective_io
  *
- * Purpose:	Routine for
+ * Purpose:     Routine for
  *              1) choose an IO option:
  *                    a) One collective IO defined by one MPI derived datatype to link through all chunks
  *              or    b) multiple chunk IOs,to do MPI-IO for each chunk, the IO mode may be adjusted
@@ -570,7 +537,7 @@ done:
  *                      3. Build up the final MPI derived datatype
  *                      4. Set up collective IO property list
  *                      5. Do IO
- *             For option b)
+ *              For option b)
  *                      1. Use MPI_gather and MPI_Bcast to obtain information of *collective/independent/none*
  *                         IO mode for each chunk of the selection
  *                      2. Depending on whether the IO mode is collective or independent or none,
@@ -579,9 +546,9 @@ done:
  *                      3. Set up collective IO property list for collective mode
  *                      4. DO IO
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -636,43 +603,9 @@ H5D_chunk_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type_info
         else
             temp_not_link_io = TRUE;
 #endif
-   } /* end else */
-
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-    if(io_option == H5D_ONE_LINK_CHUNK_IO) {
-        io_option = H5D_MULTI_CHUNK_IO; /* We can not do this with one chunk IO. */
-#ifdef  H5_HAVE_INSTRUMENTED_LIBRARY
-    {  int new_value;
-       htri_t check_prop;
-       check_prop = H5Pexist(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_LINK_TO_MULTI);
-       if(check_prop > 0) {
-           new_value = 1;
-           if(H5Pset(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_LINK_TO_MULTI, &new_value) < 0)
-                HGOTO_ERROR(H5E_IO, H5E_CANTSET, FAIL, "unable to set property value")
-
-       }
-     }/* add this property because the library changes the option from one link to multiple chunks.*/
-#endif
-    }
-    if(io_option == H5D_ONE_LINK_CHUNK_IO_MORE_OPT){
-        io_option = H5D_MULTI_CHUNK_IO_MORE_OPT;
-#ifdef  H5_HAVE_INSTRUMENTED_LIBRARY
-      { int        new_value;
-       htri_t check_prop;
-       check_prop = H5Pexist(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_LINK_TO_MULTI_OPT);
-       if(check_prop > 0) {
-           new_value = 1;
-           if(H5Pset(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_LINK_TO_MULTI_OPT, &new_value) < 0)
-                HGOTO_ERROR(H5E_IO, H5E_CANTSET, FAIL, "unable to set property value")
-
-       }
-      }/* add this property because the library changes the option from one link to multiple chunks.*/
-#endif
-    }
-#endif
+    } /* end else */
 
 #ifdef H5_HAVE_INSTRUMENTED_LIBRARY
-{
     htri_t            check_prop;
     int               new_value;
 
@@ -709,17 +642,14 @@ H5D_chunk_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type_info
                 HGOTO_ERROR(H5E_IO, H5E_CANTSET, FAIL, "unable to set property value")
         } /* end if */
     } /* end if */
-}
 #endif
 
     /* step 2:  Go ahead to do IO.*/
-#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
     if(io_option == H5D_ONE_LINK_CHUNK_IO || io_option == H5D_ONE_LINK_CHUNK_IO_MORE_OPT) {
         if(H5D_link_chunk_collective_io(io_info, type_info, fm, sum_chunk) < 0)
             HGOTO_ERROR(H5E_IO, H5E_CANTGET, FAIL, "couldn't finish linked chunk MPI-IO")
     } /* end if */
     else
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
     if(io_option == H5D_MULTI_CHUNK_IO) {
         if(H5D_multi_chunk_collective_io_no_opt(io_info, type_info, fm, dx_plist) < 0)
             HGOTO_ERROR(H5E_IO, H5E_CANTGET, FAIL, "couldn't finish multiple chunk MPI-IO")
@@ -735,14 +665,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_chunk_collective_read
+ * Function:    H5D_chunk_collective_read
  *
- * Purpose:	Reads directly from chunks in file into application memory
+ * Purpose:     Reads directly from chunks in file into application memory
  *              using collective I/O.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Tuesday, March  4, 2008
  *
  *-------------------------------------------------------------------------
@@ -766,14 +696,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_chunk_collective_write
+ * Function:    H5D_chunk_collective_write
  *
- * Purpose:	Write directly to chunks in file from application memory
+ * Purpose:     Write directly to chunks in file from application memory
  *              using collective I/O.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
+ * Programmer:  Quincey Koziol
  *              Tuesday, March  4, 2008
  *
  *-------------------------------------------------------------------------
@@ -795,21 +725,20 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_chunk_collective_write() */
 
-#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_link_chunk_collective_io
+ * Function:    H5D_link_chunk_collective_io
  *
- * Purpose:	Routine for one collective IO with one MPI derived datatype to link with all chunks
+ * Purpose:     Routine for one collective IO with one MPI derived datatype to link with all chunks
  *
  *                      1. Sort the chunk address and chunk info
  *                      2. Build up MPI derived datatype for each chunk
  *                      3. Build up the final MPI derived datatype
  *                      4. Use common collective IO routine to do MPI-IO
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -833,7 +762,7 @@ H5D_link_chunk_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type
     hbool_t            *chunk_mft_is_derived_array = NULL;      /* Flags to indicate each chunk's MPI file datatype is derived */
     hbool_t            *chunk_mbt_is_derived_array = NULL;      /* Flags to indicate each chunk's MPI memory datatype is derived */
     int                *chunk_mpi_file_counts = NULL;   /* Count of MPI file datatype for each chunk */
-    int		       *chunk_mpi_mem_counts = NULL;    /* Count of MPI memory datatype for each chunk */
+    int                *chunk_mpi_mem_counts = NULL;    /* Count of MPI memory datatype for each chunk */
     int                 mpi_code;           /* MPI return code */
     herr_t              ret_value = SUCCEED;
 
@@ -871,21 +800,22 @@ H5D_link_chunk_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type
 
         /* Check for this process having selection in this chunk */
         chunk_node = H5SL_first(fm->sel_chunks);
-	if(chunk_node == NULL) {
-            /* Set the dataspace info for I/O to NULL, this process doesn't have any I/O to perform */
-            fspace = mspace = NULL;
-	} /* end if */
-	else {
-            H5D_chunk_info_t *chunk_info;
-
-            /* Get the chunk info, for the selection in the chunk */
-            if(NULL == (chunk_info = H5SL_item(chunk_node)))
-                HGOTO_ERROR(H5E_STORAGE, H5E_CANTGET, FAIL, "couldn't get chunk info from skipped list")
 
-            /* Set the dataspace info for I/O */
-            fspace = chunk_info->fspace;
-            mspace = chunk_info->mspace;
-	} /* end else */
+        if(chunk_node == NULL) {
+                /* Set the dataspace info for I/O to NULL, this process doesn't have any I/O to perform */
+                fspace = mspace = NULL;
+        } /* end if */
+        else {
+                H5D_chunk_info_t *chunk_info;
+
+                /* Get the chunk info, for the selection in the chunk */
+                if(NULL == (chunk_info = H5SL_item(chunk_node)))
+                    HGOTO_ERROR(H5E_STORAGE, H5E_CANTGET, FAIL, "couldn't get chunk info from skipped list")
+
+                /* Set the dataspace info for I/O */
+                fspace = chunk_info->fspace;
+                mspace = chunk_info->mspace;
+        } /* end else */
 
         /* Set up the base storage address for this chunk */
         io_info->store = &ctg_store;
@@ -943,6 +873,7 @@ if(H5DEBUG(D))
             if(H5D_sort_chunk(io_info, fm, chunk_addr_info_array, sum_chunk) < 0)
                 HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSWAP, FAIL, "unable to sort chunk address")
             ctg_store.contig.dset_addr = chunk_addr_info_array[0].chunk_addr;
+
 #ifdef H5D_DEBUG
 if(H5DEBUG(D))
     HDfprintf(H5DEBUG(D),"after sorting the chunk address \n");
@@ -1055,7 +986,7 @@ if(H5DEBUG(D))
     if(chunk_mpi_file_counts)
         H5MM_xfree(chunk_mpi_file_counts);
     if(chunk_mbt_is_derived_array)
-	H5MM_xfree(chunk_mbt_is_derived_array);
+        H5MM_xfree(chunk_mbt_is_derived_array);
     if(chunk_mft_is_derived_array)
         H5MM_xfree(chunk_mft_is_derived_array);
 
@@ -1067,22 +998,21 @@ if(H5DEBUG(D))
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_link_chunk_collective_io */
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_multi_chunk_collective_io
+ * Function:    H5D_multi_chunk_collective_io
  *
- * Purpose:	To do IO per chunk according to IO mode(collective/independent/none)
+ * Purpose:     To do IO per chunk according to IO mode(collective/independent/none)
  *
  *              1. Use MPI_gather and MPI_Bcast to obtain IO mode in each chunk(collective/independent/none)
  *              2. Depending on whether the IO mode is collective or independent or none,
  *                 Create either MPI derived datatype for each chunk or just do independent IO
  *              3. Use common collective IO routine to do MPI-IO
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1169,7 +1099,7 @@ if(H5DEBUG(D))
             /* Pass in chunk's coordinates in a union. */
             store.chunk.offset  = chunk_info->coords;
             store.chunk.index   = chunk_info->index;
-	} /* end if */
+        } /* end if */
 
         /* Collective IO for this chunk,
          * Note: even there is no selection for this process, the process still
@@ -1185,10 +1115,10 @@ if(H5DEBUG(D))
             if(chunk_info) {
                 fspace = chunk_info->fspace;
                 mspace = chunk_info->mspace;
-	    } /* end if */
-	    else {
+            } /* end if */
+            else {
                 fspace = mspace = NULL;
-	    } /* end else */
+            } /* end else */
 
             /* Switch back to collective I/O */
             if(last_xfer_mode != H5FD_MPIO_COLLECTIVE) {
@@ -1208,8 +1138,8 @@ if(H5DEBUG(D))
             /* Perform the I/O */
             if(H5D_inter_collective_io(&ctg_io_info, type_info, fspace, mspace) < 0)
                 HGOTO_ERROR(H5E_IO, H5E_CANTGET, FAIL, "couldn't finish shared collective MPI-IO")
-	} /* end if */
-	else {  /* possible independent IO for this chunk */
+        } /* end if */
+        else {  /* possible independent IO for this chunk */
 #ifdef H5D_DEBUG
 if(H5DEBUG(D))
     HDfprintf(H5DEBUG(D),"inside independent IO mpi_rank = %d, chunk index = %Zu\n", mpi_rank, u);
@@ -1217,81 +1147,6 @@ if(H5DEBUG(D))
 
             HDassert(chunk_io_option[u] == 0);
 
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-            /* Check if this process has something to do with this chunk */
-            if(chunk_info) {
-                H5D_io_info_t *chk_io_info;     /* Pointer to I/O info object for this chunk */
-                H5D_chunk_ud_t udata;         /* B-tree pass-through	*/
-                void *chunk;                    /* Pointer to the data chunk in cache */
-                uint32_t accessed_bytes;          /* Total accessed size in a chunk */
-                htri_t cacheable;               /* Whether the chunk is cacheable */
-
-                /* Switch to independent I/O */
-                if(last_xfer_mode != H5FD_MPIO_INDEPENDENT) {
-                    if(H5D_ioinfo_xfer_mode(io_info, dx_plist, H5FD_MPIO_INDEPENDENT) < 0)
-                        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't switch to independent I/O")
-                    last_xfer_mode = H5FD_MPIO_INDEPENDENT;
-                } /* end if */
-
-                /* Load the chunk into cache.  But if the whole chunk is written,
-                 * simply allocate space instead of load the chunk.
-                 */
-                if(H5D_chunk_lookup(io_info->dset, io_info->dxpl_id,
-                        chunk_info->coords, chunk_info->index, &udata) < 0)
-                    HGOTO_ERROR(H5E_STORAGE, H5E_CANTGET, FAIL, "couldn't get chunk info from skipped list")
-
-                /* Load the chunk into cache and lock it. */
-                if((cacheable = H5D_chunk_cacheable(io_info, udata.addr,
-                        io_info->op_type == H5D_IO_OP_WRITE)) < 0)
-                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't tell if chunk is cacheable")
-                if(cacheable) {
-                    hbool_t entire_chunk = TRUE;         /* Whether whole chunk is selected */
-
-                    /* Compute # of bytes accessed in chunk */
-                    accessed_bytes = chunk_info->chunk_points * type_info->src_type_size;
-
-                    /* Determine if we will access all the data in the chunk */
-                    if(((io_info->op_type == H5D_IO_OP_WRITE) && (accessed_bytes != ctg_store.contig.dset_size))
-                            || (io_info->op_type != H5D_IO_OP_WRITE))
-                        entire_chunk = FALSE;
-
-                    /* Lock the chunk into the cache */
-                    if(NULL == (chunk = H5D_chunk_lock(io_info, &udata, entire_chunk)))
-                        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "unable to read raw data chunk")
-
-                    /* Set up the storage buffer information for this chunk */
-                    cpt_store.compact.buf = chunk;
-
-                    /* Point I/O info at contiguous I/O info for this chunk */
-                    chk_io_info = &cpt_io_info;
-                } /* end if */
-                else {
-                    /* Set up the storage address information for this chunk */
-                    ctg_store.contig.dset_addr = udata.addr;
-
-                    /* No chunk cached */
-                    chunk = NULL;
-
-                    /* Point I/O info at temporary I/O info for this chunk */
-                    chk_io_info = &ctg_io_info;
-                } /* end else */
-
-                if(io_info->op_type == H5D_IO_OP_WRITE) {
-                    if((io_info->io_ops.single_write)(chk_io_info, type_info,
-                            (hsize_t)chunk_info->chunk_points, chunk_info->fspace, chunk_info->mspace) < 0)
-                        HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "optimized write failed")
-                } /* end if */
-                else {
-                    if((io_info->io_ops.single_read)(chk_io_info, type_info,
-                            (hsize_t)chunk_info->chunk_points, chunk_info->fspace, chunk_info->mspace) < 0)
-                        HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "optimized read failed")
-                } /* end else */
-
-                /* Release the cache lock on the chunk. */
-                if(chunk && H5D_chunk_unlock(io_info, &udata, (io_info->op_type == H5D_IO_OP_WRITE), chunk, accessed_bytes) < 0)
-                    HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "unable to unlock raw data chunk")
-            } /* end if */
-#else /* !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS) */
             /* Set the file & memory dataspaces */
             if(chunk_info) {
                 fspace = chunk_info->fspace;
@@ -1318,7 +1173,6 @@ if(H5DEBUG(D))
   if(H5DEBUG(D))
     HDfprintf(H5DEBUG(D),"after inter collective IO\n");
 #endif
-#endif /* !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS) */
         } /* end else */
     } /* end for */
 
@@ -1333,9 +1187,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_multi_chunk_collective_io_no_opt
+ * Function:    H5D_multi_chunk_collective_io_no_opt
  *
- * Purpose:	To do collective IO without any optimization per chunk base
+ * Purpose:     To do collective IO without any optimization per chunk base
  *              The internal independent IO inside HDF5 cannot handle
  *              non-contiguous(or with holes) storage efficiently.
  *              Under this case, the one independent IO call may consist of
@@ -1352,9 +1206,9 @@ done:
  *              The HDF5 library won't do any IO management but leave it to MPI-IO to figure
  *              out.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1416,7 +1270,7 @@ if(H5DEBUG(D)) {
      /* Iterate through chunks to be operated on */
     while(chunk_node) {
         H5D_chunk_info_t *chunk_info;   /* chunk information */
-        H5D_chunk_ud_t udata;		/* B-tree pass-through	*/
+        H5D_chunk_ud_t udata;           /* B-tree pass-through */
         hbool_t make_ind, make_coll;    /* Flags to indicate that the MPI mode should change */
 
         /* Get the actual chunk information from the skip list node */
@@ -1437,20 +1291,6 @@ if(H5DEBUG(D)) {
         if(count_chunk > min_chunk)
             /* Switch to independent I/O (permanently) */
             make_ind = TRUE;
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-/* This case needs to be improved to check if the selected space
-   is regular. If all selections are regular, collective IO can still be done.
-   However, since we find an MPI-IO bug at a DOE machine(mcr) that cannot
-   handle collective I/O selection for this case correctly,
-   we turn off this optimization but leave the following code
-   for future optimization. Otherwise, the following else {} doesn't make sense.
-   KY 2006/8/4/ */
-        else {
-            /* Switch to independent I/O (temporarily) */
-            make_ind = TRUE;
-            make_coll = TRUE;
-        } /* end else */
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
 
         /* Retrieve the chunk's address */
         if(H5D_chunk_lookup(io_info->dset, io_info->dxpl_id, chunk_info->coords,
@@ -1542,14 +1382,14 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_inter_collective_io
+ * Function:    H5D_inter_collective_io
  *
- * Purpose:	Routine for the shared part of collective IO between multiple chunk
+ * Purpose:     Routine for the shared part of collective IO between multiple chunk
  *              collective IO and contiguous collective IO
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1611,13 +1451,13 @@ if(H5DEBUG(D))
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_final_collective_io
+ * Function:    H5D_final_collective_io
  *
- * Purpose:	Routine for the common part of collective IO with different storages.
+ * Purpose:     Routine for the common part of collective IO with different storages.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1626,7 +1466,7 @@ static herr_t
 H5D_final_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     hsize_t mpi_buf_count, MPI_Datatype *mpi_file_type, MPI_Datatype *mpi_buf_type)
 {
-    hbool_t	plist_is_setup = FALSE; /* Whether the dxpl has been customized */
+    hbool_t     plist_is_setup = FALSE; /* Whether the dxpl has been customized */
     herr_t      ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_final_collective_io)
@@ -1638,7 +1478,7 @@ H5D_final_collective_io(H5D_io_info_t *io_info, const H5D_type_info_t *type_info
 
     if(io_info->op_type == H5D_IO_OP_WRITE) {
         if((io_info->io_ops.single_write)(io_info, type_info, mpi_buf_count, NULL, NULL) < 0)
-	    HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "optimized write failed")
+            HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "optimized write failed")
     } /* end if */
     else {
         if((io_info->io_ops.single_read)(io_info, type_info, mpi_buf_count, NULL, NULL) < 0)
@@ -1658,12 +1498,11 @@ if(H5DEBUG(D))
       FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_final_collective_io */
 
-#ifdef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_sort_chunk
+ * Function:    H5D_sort_chunk
  *
- * Purpose:	Routine to sort chunks in increasing order of chunk address
+ * Purpose:     Routine to sort chunks in increasing order of chunk address
  *              Each chunk address is also obtained.
  *
  * Description:
@@ -1678,9 +1517,9 @@ if(H5DEBUG(D))
  *                     many_chunk_opt                         : flag to optimize the way to obtain chunk addresses
  *                                                              for many chunks
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1699,7 +1538,7 @@ H5D_sort_chunk(H5D_io_info_t *io_info, const H5D_chunk_map_t *fm,
     int             mpi_size;                   /* Number of MPI processes */
     int             mpi_code;                   /* MPI return code */
     int             i;                          /* Local index variable */
-    herr_t	    ret_value = SUCCEED;        /* Return value		*/
+    herr_t          ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5D_sort_chunk)
 
@@ -1740,14 +1579,15 @@ if(H5DEBUG(D))
         /* Retrieve all the chunk addresses with process 0 */
         if((mpi_rank = H5F_mpi_get_rank(io_info->dset->oloc.file)) < 0)
             HGOTO_ERROR(H5E_IO, H5E_MPI, FAIL, "unable to obtain mpi rank")
-	if(mpi_rank == 0) {
+
+        if(mpi_rank == 0) {
             if(H5D_chunk_addrmap(io_info, total_chunk_addr_array) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get chunk address")
-	} /* end if */
+        } /* end if */
 
-	/* Broadcasting the MPI_IO option info. and chunk address info. */
-	if(MPI_SUCCESS != (mpi_code = MPI_Bcast(total_chunk_addr_array, (int)(sizeof(haddr_t) * fm->layout->u.chunk.nchunks), MPI_BYTE, (int)0, io_info->comm)))
-	   HMPI_GOTO_ERROR(FAIL, "MPI_BCast failed", mpi_code)
+        /* Broadcasting the MPI_IO option info. and chunk address info. */
+        if(MPI_SUCCESS != (mpi_code = MPI_Bcast(total_chunk_addr_array, (int)(sizeof(haddr_t) * fm->layout->u.chunk.nchunks), MPI_BYTE, (int)0, io_info->comm)))
+           HMPI_GOTO_ERROR(FAIL, "MPI_BCast failed", mpi_code)
     } /* end if */
 
     /* Start at first node in chunk skip list */
@@ -1801,13 +1641,12 @@ done:
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D_sort_chunk() */
-#endif /* H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_obtain_mpio_mode
+ * Function:    H5D_obtain_mpio_mode
  *
- * Purpose:	Routine to obtain each io mode(collective,independent or none) for each chunk;
+ * Purpose:     Routine to obtain each io mode(collective,independent or none) for each chunk;
  *              Each chunk address is also obtained.
  *
  * Description:
@@ -1833,9 +1672,9 @@ done:
  *              Output: uint8_t assign_io_mode[], : IO mode, collective, independent or none
  *                      haddr_t chunk_addr[],     : chunk address array for each chunk
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Muqun Yang
+ * Programmer:  Muqun Yang
  *              Monday, Feb. 13th, 2006
  *
  *-------------------------------------------------------------------------
@@ -1846,9 +1685,7 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
 {
     int               total_chunks;
     unsigned          percent_nproc_per_chunk, threshold_nproc_per_chunk;
-#if defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) && defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
     H5FD_mpio_chunk_opt_t chunk_opt_mode;
-#endif
     uint8_t*          io_mode_info = NULL;
     uint8_t*          recv_io_mode_info = NULL;
     uint8_t*          mergebuf = NULL;
@@ -1881,7 +1718,6 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
     /* Setup parameters */
     H5_ASSIGN_OVERFLOW(total_chunks, fm->layout->u.chunk.nchunks, hsize_t, int);
     percent_nproc_per_chunk = H5P_peek_unsigned(dx_plist, H5D_XFER_MPIO_CHUNK_OPT_RATIO_NAME);
-#if defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) && defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
     chunk_opt_mode = (H5FD_mpio_chunk_opt_t)H5P_peek_unsigned(dx_plist, H5D_XFER_MPIO_CHUNK_OPT_HARD_NAME);
     if((chunk_opt_mode == H5FD_MPIO_CHUNK_MULTI_IO) || (percent_nproc_per_chunk == 0)) {
         if(H5D_chunk_addrmap(io_info, chunk_addr) < 0)
@@ -1891,7 +1727,6 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
 
         HGOTO_DONE(SUCCEED)
     } /* end if */
-#endif
     threshold_nproc_per_chunk = mpi_size * percent_nproc_per_chunk/100;
 
     /* Allocate memory */
@@ -1907,16 +1742,7 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
     while(chunk_node) {
         chunk_info    = H5SL_item(chunk_node);
 
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-        /* regularity information: 1, selection information: 2 */
-        if(H5S_SELECT_IS_REGULAR(chunk_info->fspace) == TRUE &&
-                H5S_SELECT_IS_REGULAR(chunk_info->mspace) == TRUE)
-#endif
-            io_mode_info[chunk_info->index] = H5D_CHUNK_SELECT_REG; /* this chunk is selected and is "regular" without defining H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS. */
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-        else
-            io_mode_info[chunk_info->index] = H5D_CHUNK_SELECT_IRREG; /* this chunk is selected and is irregular*/
-#endif
+            io_mode_info[chunk_info->index] = H5D_CHUNK_SELECT_REG; /* this chunk is selected and is "regular" */
         chunk_node = H5SL_next(chunk_node);
     } /* end while */
 
@@ -1928,23 +1754,14 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
     if(mpi_rank == root) {
         int               nproc;
         int*              nproc_per_chunk;
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-        int*              ind_this_chunk;
-#endif
 
         /* pre-computing: calculate number of processes and
             regularity of the selection occupied in each chunk */
         nproc_per_chunk = (int*)H5MM_calloc(total_chunks * sizeof(int));
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-        ind_this_chunk   = (int*)H5MM_calloc(total_chunks * sizeof(int));
-#endif
 
         /* calculating the chunk address */
         if(H5D_chunk_addrmap(io_info, chunk_addr) < 0) {
             HDfree(nproc_per_chunk);
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-            HDfree(ind_this_chunk);
-#endif
             HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get chunk address")
         } /* end if */
 
@@ -1956,29 +1773,14 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
             for(ic = 0; ic < total_chunks; ic++, tmp_recv_io_mode_info++) {
                 if(*tmp_recv_io_mode_info != 0) {
                     nproc_per_chunk[ic]++;
-#ifndef H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS
-                    if(*tmp_recv_io_mode_info == H5D_CHUNK_SELECT_IRREG)
-                        ind_this_chunk[ic] = 1;
-#endif
                 } /* end if */
-#ifndef H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS
-                else {
-                    /*checking whether we have a selection in this chunk */
-                    ind_this_chunk[ic] = 1;
-                } /* end else */
-#endif
             } /* end for */
         } /* end for */
 
         /* Calculating MPIO mode for each chunk (collective, independent, none) */
         for(ic = 0; ic < total_chunks; ic++) {
             if(nproc_per_chunk[ic] > MAX(1, threshold_nproc_per_chunk)) {
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-                if(!ind_this_chunk[ic])
-                    assign_io_mode[ic] = H5D_CHUNK_IO_MODE_COL;
-#else
                 assign_io_mode[ic] = H5D_CHUNK_IO_MODE_COL;
-#endif
             } /* end if */
         } /* end for */
 
@@ -1988,9 +1790,6 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
         HDmemcpy(tempbuf, chunk_addr, sizeof(haddr_t) * total_chunks);
 
         HDfree(nproc_per_chunk);
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-        HDfree(ind_this_chunk);
-#endif
     } /* end if */
 
     /* Broadcasting the MPI_IO option info. and chunk address info. */
@@ -2003,11 +1802,6 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
 #ifdef H5_HAVE_INSTRUMENTED_LIBRARY
     check_prop = H5Pexist(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_MULTI_RATIO_COLL_NAME);
     if(check_prop > 0) {
-#if !defined(H5_MPI_COMPLEX_DERIVED_DATATYPE_WORKS) || !defined(H5_MPI_SPECIAL_COLLECTIVE_IO_WORKS)
-        new_value = 0;
-        if(H5Pset(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_MULTI_RATIO_COLL_NAME, &new_value) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_UNSUPPORTED, FAIL, "unable to set property value")
-#else
         for(ic = 0; ic < total_chunks; ic++) {
             if(assign_io_mode[ic] == H5D_CHUNK_IO_MODE_COL) {
                 new_value = 0;
@@ -2016,7 +1810,6 @@ H5D_obtain_mpio_mode(H5D_io_info_t* io_info, H5D_chunk_map_t *fm,
                 break;
             } /* end if */
         } /* end for */
-#endif
     } /* end if */
 
     check_prop = H5Pexist(io_info->dxpl_id, H5D_XFER_COLL_CHUNK_MULTI_RATIO_IND_NAME);