[svn-r6825] Purpose:

    New feature/enhancement

Description:
    Chunked datasets are handled poorly in several circumstances involving
certain selections and chunks that are too large for the chunk cache and/or
chunks with filters, causing the chunk to be read from disk multiple times.

Solution:
    Rearrange raw data I/O infrastructure to handle chunked datasets in a much
more friendly way by creating a selection in memory and on disk for each chunk
in a chunked dataset and performing all of the I/O on that chunk at one time.

    There are still some scalability (the current code attempts to
create a selection for all the chunks in the dataset, instead of just the
chunks that are accessed, requiring portions of the istore.c and fillval.c
tests to be commented out) and performance issues, but checking this in will
allow the changes to be tested by a much wider audience while I address the
remaining issues.


Platforms tested:
    h5committested, FreeBSD 4.8 (sleipnir) serial & parallel, Linux 2.4 (eirene)

1 files changed, 10 insertions, 6 deletions

diff --git a/src/H5S.c b/src/H5S.c
index d5eb588..08212c4 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -56,7 +56,7 @@ H5FL_DEFINE(H5S_simple_t);
 H5FL_DEFINE(H5S_t);
 
 /* Declare a free list to manage the array's of hsize_t's */
-H5FL_ARR_DEFINE(hsize_t,H5S_MAX_RANK);
+H5FL_ARR_DEFINE(hsize_t,-1);
 
 /* Declare a free list to manage the array's of hssize_t's */
 H5FL_ARR_DEFINE(hssize_t,H5S_MAX_RANK);
@@ -1548,7 +1548,11 @@ done:
  *-------------------------------------------------------------------------
  */
 H5S_conv_t *
-H5S_find (const H5S_t *mem_space, const H5S_t *file_space, unsigned flags)
+H5S_find (const H5S_t *mem_space, const H5S_t *file_space, unsigned
+#ifndef H5_HAVE_PARALLEL
+UNUSED
+#endif /* H5_HAVE_PARALLEL */
+flags)
 {
     H5S_conv_t	*path=NULL;  /* Space conversion path */
 #ifdef H5_HAVE_PARALLEL
@@ -1780,7 +1784,7 @@ H5Screate_simple(int rank, const hsize_t dims[/*rank*/],
     }
 
     /* Create the space and set the extent */
-    if(NULL==(space=H5S_create_simple(rank,dims,maxdims)))
+    if(NULL==(space=H5S_create_simple((unsigned)rank,dims,maxdims)))
         HGOTO_ERROR (H5E_DATASPACE, H5E_CANTCREATE, FAIL, "can't create simple dataspace");
     
     /* Atomize */
@@ -1817,7 +1821,7 @@ done:
  *-------------------------------------------------------------------------
  */
 H5S_t *
-H5S_create_simple(int rank, const hsize_t dims[/*rank*/],
+H5S_create_simple(unsigned rank, const hsize_t dims[/*rank*/],
 		  const hsize_t maxdims[/*rank*/])
 {
     H5S_t	*ret_value;     /* Return value */
@@ -1825,12 +1829,12 @@ H5S_create_simple(int rank, const hsize_t dims[/*rank*/],
     FUNC_ENTER_NOAPI(H5S_create_simple, NULL);
 
     /* Check arguments */
-    assert(rank>=0 && rank <=H5S_MAX_RANK);
+    assert(rank <=H5S_MAX_RANK);
 
     /* Create the space and set the extent */
     if(NULL==(ret_value=H5S_create(H5S_SIMPLE)))
         HGOTO_ERROR (H5E_DATASPACE, H5E_CANTCREATE, NULL, "can't create simple dataspace");
-    if(H5S_set_extent_simple(ret_value,(unsigned)rank,dims,maxdims)<0)
+    if(H5S_set_extent_simple(ret_value,rank,dims,maxdims)<0)
         HGOTO_ERROR (H5E_DATASPACE, H5E_CANTINIT, NULL, "can't set dimensions");
     
 done: