[svn-r8303] Purpose:

    Code optimization

Description:
    Compute the size of a chunk once, when the layout information is set,
instead of each time I/O is performed on the chunk.

Platforms tested:
    h5committest
    Solaris 2.7 (arabica)

5 files changed, 55 insertions, 79 deletions

diff --git a/src/H5D.c b/src/H5D.c
index 18f4c58..fa20fd4 100644
--- a/src/H5D.c
+++ b/src/H5D.c
@@ -1845,7 +1845,6 @@ H5D_create(H5G_entry_t *loc, const char *name, hid_t type_id, const H5S_t *space
     const H5T_t         *type;                  /* Datatype for dataset */
     H5D_t		*new_dset = NULL;
     int		        i, ndims;
-    hsize_t 		comp_data_size;
     unsigned		u;
     hsize_t		max_dim[H5O_LAYOUT_NDIMS]={0};
     H5F_t		*file=NULL;
@@ -2041,11 +2040,16 @@ H5D_create(H5G_entry_t *loc, const char *name, hid_t type_id, const H5S_t *space
             /* Set the dataset's chunk sizes from the property list's chunk sizes */
             for (u=0; u<new_dset->layout.ndims-1; u++)
                 new_dset->layout.dim[u] = chunk_size[u];
+
+            /* Compute the total size of a chunk */
+            for (u=0, new_dset->layout.chunk_size=1; u<new_dset->layout.ndims; u++)
+                new_dset->layout.chunk_size *= new_dset->layout.dim[u];
             break;
 
         case H5D_COMPACT:
             {
                 hssize_t tmp_size;      /* Temporary holder for raw data size */
+                hsize_t	comp_data_size;
 
                 /*
                  * Compact dataset is stored in dataset object header message of 
@@ -2060,10 +2064,8 @@ H5D_create(H5G_entry_t *loc, const char *name, hid_t type_id, const H5S_t *space
                 comp_data_size=H5O_MAX_SIZE-H5O_layout_meta_size(file, &(new_dset->layout));
                 if(new_dset->layout.size > comp_data_size)
                     HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "compact dataset size is bigger than header message maximum size")
-                if ((ndims=H5S_get_simple_extent_dims(space, new_dset->layout.dim, max_dim))<0) 
-                    HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to initialize dimension size of compact dataset storage")
-                /* remember to check if size is small enough to fit header message */
-
+                if (H5S_get_simple_extent_dims(space, new_dset->layout.dim, NULL)<0) 
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to initialize dimension size of compact dataset storage");
             }
 
             break;
diff --git a/src/H5Distore.c b/src/H5Distore.c
index 95876e9..3efc914 100644
--- a/src/H5Distore.c
+++ b/src/H5Distore.c
@@ -212,8 +212,8 @@ H5B_class_t H5B_ISTORE[1] = {{
 /* Declare a free list to manage H5F_rdcc_ent_t objects */
 H5FL_DEFINE_STATIC(H5F_rdcc_ent_t);
 
-/* Declare a PQ free list to manage the H5F_rdcc_ent_ptr_t array information */
-H5FL_ARR_DEFINE_STATIC(H5F_rdcc_ent_ptr_t,-1);
+/* Declare a free list to manage the H5F_rdcc_ent_ptr_t sequence information */
+H5FL_SEQ_DEFINE_STATIC(H5F_rdcc_ent_ptr_t);
 
 
 /*-------------------------------------------------------------------------
@@ -882,7 +882,7 @@ H5F_istore_init (H5F_t *f)
     HDmemset (rdcc, 0, sizeof(H5F_rdcc_t));
     if (f->shared->rdcc_nbytes>0 && f->shared->rdcc_nelmts>0) {
 	rdcc->nslots = f->shared->rdcc_nelmts;
-	rdcc->slot = H5FL_ARR_CALLOC (H5F_rdcc_ent_ptr_t,rdcc->nslots);
+	rdcc->slot = H5FL_SEQ_CALLOC (H5F_rdcc_ent_ptr_t,rdcc->nslots);
 	if (NULL==rdcc->slot)
 	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");
     }
@@ -1183,7 +1183,7 @@ H5F_istore_dest (H5F_t *f, hid_t dxpl_id)
     if (nerrors)
 	HGOTO_ERROR (H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush one or more raw data chunks");
 
-    H5FL_ARR_FREE (H5F_rdcc_ent_ptr_t,rdcc->slot);
+    H5FL_SEQ_FREE (H5F_rdcc_ent_ptr_t,rdcc->slot);
     HDmemset (rdcc, 0, sizeof(H5F_rdcc_t));
 
 done:
@@ -1357,7 +1357,6 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
     unsigned		u;			/*counters		*/
     H5F_istore_ud1_t	udata;			/*B-tree pass-through	*/
     size_t		chunk_size=0;		/*size of a chunk	*/
-    hsize_t             tempchunk_size;
     herr_t		status;			/*func return status	*/
     void		*chunk=NULL;		/*the file chunk	*/
     void		*ret_value;	        /*return value		*/
@@ -1405,9 +1404,8 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
         HDfflush(stderr);
 #endif
         rdcc->nhits++;
-        for (u=0, tempchunk_size=1; u<layout->ndims; u++)
-            tempchunk_size *= layout->dim[u];
-        H5_ASSIGN_OVERFLOW(chunk_size,tempchunk_size,hsize_t,size_t);
+        assert(layout->chunk_size>0);
+        H5_ASSIGN_OVERFLOW(chunk_size,layout->chunk_size,hsize_t,size_t);
         if (NULL==(chunk=H5MM_malloc (chunk_size)))
             HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for raw data chunk");
         
@@ -1417,11 +1415,10 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
          * Not in the cache.  Read it from the file and count this as a miss
          * if it's in the file or an init if it isn't.
          */
-        for (u=0, tempchunk_size=1; u<layout->ndims; u++) {
+        for (u=0; u<layout->ndims; u++)
             udata.key.offset[u] = offset[u];
-            tempchunk_size *= layout->dim[u];
-        }
-        H5_ASSIGN_OVERFLOW(chunk_size,tempchunk_size,hsize_t,size_t);
+        assert(layout->chunk_size>0);
+        H5_ASSIGN_OVERFLOW(chunk_size,layout->chunk_size,hsize_t,size_t);
         udata.mesg = *layout;
         udata.addr = HADDR_UNDEF;
         status = H5B_find (f, dxpl_id, H5B_ISTORE, layout->addr, &udata);
@@ -1637,17 +1634,15 @@ H5F_istore_unlock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
          */
         if (dirty) {
             H5F_rdcc_ent_t x;
-            hsize_t tempchunk_size;
 
             HDmemset (&x, 0, sizeof x);
             x.dirty = TRUE;
             x.layout = H5O_copy (H5O_LAYOUT_ID, layout, NULL);
             x.pline = H5O_copy (H5O_PLINE_ID, pline, NULL);
-            for (u=0, tempchunk_size=1; u<layout->ndims; u++) {
+            for (u=0; u<layout->ndims; u++)
                 x.offset[u] = offset[u];
-                tempchunk_size *= layout->dim[u];
-            }
-            H5_ASSIGN_OVERFLOW(x.chunk_size,tempchunk_size,hsize_t,size_t);
+            assert(layout->chunk_size>0);
+            H5_ASSIGN_OVERFLOW(x.chunk_size,layout->chunk_size,hsize_t,size_t);
             x.alloc_size = x.chunk_size;
             x.chunk = chunk;
 
@@ -1699,7 +1694,6 @@ H5F_istore_readvv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache, hid_t dxp
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
     void *buf)
 {
-    hsize_t		chunk_size;     /* Chunk size, in bytes */
     haddr_t	        chunk_addr;     /* Chunk address on disk */
     hssize_t	        chunk_coords_in_elmts[H5O_LAYOUT_NDIMS];
     size_t		u;              /* Local index variables */
@@ -1719,10 +1713,6 @@ H5F_istore_readvv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache, hid_t dxp
     assert(mem_offset_arr);
     assert(buf);
 
-    /* Compute chunk size */
-    for (u=0, chunk_size=1; u<layout->ndims; u++)
-        chunk_size *= layout->dim[u];
-
 #ifndef NDEBUG
     for (u=0; u<layout->ndims; u++)
         assert(chunk_coords[u]>=0); /*negative coordinates not supported (yet) */
@@ -1739,7 +1729,7 @@ for(u=0; u<layout->ndims; u++)
 #endif /* QAK */
     chunk_addr=H5F_istore_get_addr(f, dxpl_id, layout, chunk_coords_in_elmts);
 #ifdef QAK
-HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,chunk_size);
+HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,layout->chunk_size);
 HDfprintf(stderr,"%s: chunk_len_arr[%Zu]=%Zu\n",FUNC,*chunk_curr_seq,chunk_len_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: chunk_offset_arr[%Zu]=%Hu\n",FUNC,*chunk_curr_seq,chunk_offset_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: mem_len_arr[%Zu]=%Zu\n",FUNC,*mem_curr_seq,mem_len_arr[*mem_curr_seq]);
@@ -1752,9 +1742,9 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
      * for the chunk has been defined, then don't load the chunk into the
      * cache, just write the data to it directly.
      */
-    if (chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 &&
+    if (layout->chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 &&
             chunk_addr!=HADDR_UNDEF) {
-        if ((ret_value=H5F_contig_readvv(f, chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
+        if ((ret_value=H5F_contig_readvv(f, layout->chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
             HGOTO_ERROR (H5E_IO, H5E_READERROR, FAIL, "unable to read raw data to file");
     } /* end if */
     else {
@@ -1811,7 +1801,6 @@ H5F_istore_writevv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache,
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
     const void *buf)
 {
-    hsize_t		chunk_size;     /* Chunk size, in bytes */
     haddr_t	        chunk_addr;     /* Chunk address on disk */
     hssize_t	        chunk_coords_in_elmts[H5O_LAYOUT_NDIMS];
     size_t		u;              /* Local index variables */
@@ -1831,10 +1820,6 @@ H5F_istore_writevv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache,
     assert(mem_offset_arr);
     assert(buf);
 
-    /* Compute chunk size */
-    for (u=0, chunk_size=1; u<layout->ndims; u++)
-        chunk_size *= layout->dim[u];
-
 #ifndef NDEBUG
     for (u=0; u<layout->ndims; u++)
         assert(chunk_coords[u]>=0); /*negative coordinates not supported (yet) */
@@ -1851,7 +1836,7 @@ for(u=0; u<layout->ndims; u++)
 #endif /* QAK */
     chunk_addr=H5F_istore_get_addr(f, dxpl_id, layout, chunk_coords_in_elmts);
 #ifdef QAK
-HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,chunk_size);
+HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,layout->chunk_size);
 HDfprintf(stderr,"%s: chunk_len_arr[%Zu]=%Zu\n",FUNC,*chunk_curr_seq,chunk_len_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: chunk_offset_arr[%Zu]=%Hu\n",FUNC,*chunk_curr_seq,chunk_offset_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: mem_len_arr[%Zu]=%Zu\n",FUNC,*mem_curr_seq,mem_len_arr[*mem_curr_seq]);
@@ -1869,14 +1854,14 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
      * writing to other elements in the same chunk.  Do a direct
      * write-through of only the elements requested.
      */
-    if ((chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 && chunk_addr!=HADDR_UNDEF)
+    if ((layout->chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 && chunk_addr!=HADDR_UNDEF)
         || (IS_H5FD_MPI(f) && (H5F_ACC_RDWR & f->shared->flags))) {
 #ifdef H5_HAVE_PARALLEL
         /* Additional sanity check when operating in parallel */
         if (chunk_addr==HADDR_UNDEF || dcpl_cache->pline.nused>0)
             HGOTO_ERROR (H5E_IO, H5E_WRITEERROR, FAIL, "unable to locate raw data chunk");
 #endif /* H5_HAVE_PARALLEL */
-        if ((ret_value=H5F_contig_writevv(f, chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
+        if ((ret_value=H5F_contig_writevv(f, layout->chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
             HGOTO_ERROR (H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file");
     } /* end if */
     else {
@@ -1889,7 +1874,7 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
          * Lock the chunk, copy from application to chunk, then unlock the
          * chunk.
          */
-        if(chunk_max_nseq==1 && chunk_len_arr[0] == chunk_size)
+        if(chunk_max_nseq==1 && chunk_len_arr[0] == layout->chunk_size)
             relax = TRUE;
         else
             relax = FALSE;
@@ -2177,10 +2162,9 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
      * Setup indice to go through all chunks. (Future improvement
      * should allocate only chunks that have no file space assigned yet.
      */
-    for (u=0, chunk_size=1; u<layout->ndims; u++) {
+    for (u=0; u<layout->ndims; u++)
         chunk_offset[u] = 0;
-        chunk_size *= layout->dim[u];
-    } /* end for */
+    chunk_size = layout->chunk_size;
 
     /* Check the dataset's fill-value status */
     if (H5P_is_fill_value_defined(&fill, &fill_status) < 0)
diff --git a/src/H5Fistore.c b/src/H5Fistore.c
index 95876e9..3efc914 100644
--- a/src/H5Fistore.c
+++ b/src/H5Fistore.c
@@ -212,8 +212,8 @@ H5B_class_t H5B_ISTORE[1] = {{
 /* Declare a free list to manage H5F_rdcc_ent_t objects */
 H5FL_DEFINE_STATIC(H5F_rdcc_ent_t);
 
-/* Declare a PQ free list to manage the H5F_rdcc_ent_ptr_t array information */
-H5FL_ARR_DEFINE_STATIC(H5F_rdcc_ent_ptr_t,-1);
+/* Declare a free list to manage the H5F_rdcc_ent_ptr_t sequence information */
+H5FL_SEQ_DEFINE_STATIC(H5F_rdcc_ent_ptr_t);
 
 
 /*-------------------------------------------------------------------------
@@ -882,7 +882,7 @@ H5F_istore_init (H5F_t *f)
     HDmemset (rdcc, 0, sizeof(H5F_rdcc_t));
     if (f->shared->rdcc_nbytes>0 && f->shared->rdcc_nelmts>0) {
 	rdcc->nslots = f->shared->rdcc_nelmts;
-	rdcc->slot = H5FL_ARR_CALLOC (H5F_rdcc_ent_ptr_t,rdcc->nslots);
+	rdcc->slot = H5FL_SEQ_CALLOC (H5F_rdcc_ent_ptr_t,rdcc->nslots);
 	if (NULL==rdcc->slot)
 	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");
     }
@@ -1183,7 +1183,7 @@ H5F_istore_dest (H5F_t *f, hid_t dxpl_id)
     if (nerrors)
 	HGOTO_ERROR (H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush one or more raw data chunks");
 
-    H5FL_ARR_FREE (H5F_rdcc_ent_ptr_t,rdcc->slot);
+    H5FL_SEQ_FREE (H5F_rdcc_ent_ptr_t,rdcc->slot);
     HDmemset (rdcc, 0, sizeof(H5F_rdcc_t));
 
 done:
@@ -1357,7 +1357,6 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
     unsigned		u;			/*counters		*/
     H5F_istore_ud1_t	udata;			/*B-tree pass-through	*/
     size_t		chunk_size=0;		/*size of a chunk	*/
-    hsize_t             tempchunk_size;
     herr_t		status;			/*func return status	*/
     void		*chunk=NULL;		/*the file chunk	*/
     void		*ret_value;	        /*return value		*/
@@ -1405,9 +1404,8 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
         HDfflush(stderr);
 #endif
         rdcc->nhits++;
-        for (u=0, tempchunk_size=1; u<layout->ndims; u++)
-            tempchunk_size *= layout->dim[u];
-        H5_ASSIGN_OVERFLOW(chunk_size,tempchunk_size,hsize_t,size_t);
+        assert(layout->chunk_size>0);
+        H5_ASSIGN_OVERFLOW(chunk_size,layout->chunk_size,hsize_t,size_t);
         if (NULL==(chunk=H5MM_malloc (chunk_size)))
             HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for raw data chunk");
         
@@ -1417,11 +1415,10 @@ H5F_istore_lock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id, con
          * Not in the cache.  Read it from the file and count this as a miss
          * if it's in the file or an init if it isn't.
          */
-        for (u=0, tempchunk_size=1; u<layout->ndims; u++) {
+        for (u=0; u<layout->ndims; u++)
             udata.key.offset[u] = offset[u];
-            tempchunk_size *= layout->dim[u];
-        }
-        H5_ASSIGN_OVERFLOW(chunk_size,tempchunk_size,hsize_t,size_t);
+        assert(layout->chunk_size>0);
+        H5_ASSIGN_OVERFLOW(chunk_size,layout->chunk_size,hsize_t,size_t);
         udata.mesg = *layout;
         udata.addr = HADDR_UNDEF;
         status = H5B_find (f, dxpl_id, H5B_ISTORE, layout->addr, &udata);
@@ -1637,17 +1634,15 @@ H5F_istore_unlock(H5F_t *f, const H5D_dxpl_cache_t *dxpl_cache, hid_t dxpl_id,
          */
         if (dirty) {
             H5F_rdcc_ent_t x;
-            hsize_t tempchunk_size;
 
             HDmemset (&x, 0, sizeof x);
             x.dirty = TRUE;
             x.layout = H5O_copy (H5O_LAYOUT_ID, layout, NULL);
             x.pline = H5O_copy (H5O_PLINE_ID, pline, NULL);
-            for (u=0, tempchunk_size=1; u<layout->ndims; u++) {
+            for (u=0; u<layout->ndims; u++)
                 x.offset[u] = offset[u];
-                tempchunk_size *= layout->dim[u];
-            }
-            H5_ASSIGN_OVERFLOW(x.chunk_size,tempchunk_size,hsize_t,size_t);
+            assert(layout->chunk_size>0);
+            H5_ASSIGN_OVERFLOW(x.chunk_size,layout->chunk_size,hsize_t,size_t);
             x.alloc_size = x.chunk_size;
             x.chunk = chunk;
 
@@ -1699,7 +1694,6 @@ H5F_istore_readvv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache, hid_t dxp
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
     void *buf)
 {
-    hsize_t		chunk_size;     /* Chunk size, in bytes */
     haddr_t	        chunk_addr;     /* Chunk address on disk */
     hssize_t	        chunk_coords_in_elmts[H5O_LAYOUT_NDIMS];
     size_t		u;              /* Local index variables */
@@ -1719,10 +1713,6 @@ H5F_istore_readvv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache, hid_t dxp
     assert(mem_offset_arr);
     assert(buf);
 
-    /* Compute chunk size */
-    for (u=0, chunk_size=1; u<layout->ndims; u++)
-        chunk_size *= layout->dim[u];
-
 #ifndef NDEBUG
     for (u=0; u<layout->ndims; u++)
         assert(chunk_coords[u]>=0); /*negative coordinates not supported (yet) */
@@ -1739,7 +1729,7 @@ for(u=0; u<layout->ndims; u++)
 #endif /* QAK */
     chunk_addr=H5F_istore_get_addr(f, dxpl_id, layout, chunk_coords_in_elmts);
 #ifdef QAK
-HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,chunk_size);
+HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,layout->chunk_size);
 HDfprintf(stderr,"%s: chunk_len_arr[%Zu]=%Zu\n",FUNC,*chunk_curr_seq,chunk_len_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: chunk_offset_arr[%Zu]=%Hu\n",FUNC,*chunk_curr_seq,chunk_offset_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: mem_len_arr[%Zu]=%Zu\n",FUNC,*mem_curr_seq,mem_len_arr[*mem_curr_seq]);
@@ -1752,9 +1742,9 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
      * for the chunk has been defined, then don't load the chunk into the
      * cache, just write the data to it directly.
      */
-    if (chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 &&
+    if (layout->chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 &&
             chunk_addr!=HADDR_UNDEF) {
-        if ((ret_value=H5F_contig_readvv(f, chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
+        if ((ret_value=H5F_contig_readvv(f, layout->chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
             HGOTO_ERROR (H5E_IO, H5E_READERROR, FAIL, "unable to read raw data to file");
     } /* end if */
     else {
@@ -1811,7 +1801,6 @@ H5F_istore_writevv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache,
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[],
     const void *buf)
 {
-    hsize_t		chunk_size;     /* Chunk size, in bytes */
     haddr_t	        chunk_addr;     /* Chunk address on disk */
     hssize_t	        chunk_coords_in_elmts[H5O_LAYOUT_NDIMS];
     size_t		u;              /* Local index variables */
@@ -1831,10 +1820,6 @@ H5F_istore_writevv(H5F_t *f, const struct H5D_dxpl_cache_t *dxpl_cache,
     assert(mem_offset_arr);
     assert(buf);
 
-    /* Compute chunk size */
-    for (u=0, chunk_size=1; u<layout->ndims; u++)
-        chunk_size *= layout->dim[u];
-
 #ifndef NDEBUG
     for (u=0; u<layout->ndims; u++)
         assert(chunk_coords[u]>=0); /*negative coordinates not supported (yet) */
@@ -1851,7 +1836,7 @@ for(u=0; u<layout->ndims; u++)
 #endif /* QAK */
     chunk_addr=H5F_istore_get_addr(f, dxpl_id, layout, chunk_coords_in_elmts);
 #ifdef QAK
-HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,chunk_size);
+HDfprintf(stderr,"%s: chunk_addr=%a, chunk_size=%Hu\n",FUNC,chunk_addr,layout->chunk_size);
 HDfprintf(stderr,"%s: chunk_len_arr[%Zu]=%Zu\n",FUNC,*chunk_curr_seq,chunk_len_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: chunk_offset_arr[%Zu]=%Hu\n",FUNC,*chunk_curr_seq,chunk_offset_arr[*chunk_curr_seq]);
 HDfprintf(stderr,"%s: mem_len_arr[%Zu]=%Zu\n",FUNC,*mem_curr_seq,mem_len_arr[*mem_curr_seq]);
@@ -1869,14 +1854,14 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
      * writing to other elements in the same chunk.  Do a direct
      * write-through of only the elements requested.
      */
-    if ((chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 && chunk_addr!=HADDR_UNDEF)
+    if ((layout->chunk_size>f->shared->rdcc_nbytes && dcpl_cache->pline.nused==0 && chunk_addr!=HADDR_UNDEF)
         || (IS_H5FD_MPI(f) && (H5F_ACC_RDWR & f->shared->flags))) {
 #ifdef H5_HAVE_PARALLEL
         /* Additional sanity check when operating in parallel */
         if (chunk_addr==HADDR_UNDEF || dcpl_cache->pline.nused>0)
             HGOTO_ERROR (H5E_IO, H5E_WRITEERROR, FAIL, "unable to locate raw data chunk");
 #endif /* H5_HAVE_PARALLEL */
-        if ((ret_value=H5F_contig_writevv(f, chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
+        if ((ret_value=H5F_contig_writevv(f, layout->chunk_size, chunk_addr, chunk_max_nseq, chunk_curr_seq, chunk_len_arr, chunk_offset_arr, mem_max_nseq, mem_curr_seq, mem_len_arr, mem_offset_arr, dxpl_id, buf))<0)
             HGOTO_ERROR (H5E_IO, H5E_WRITEERROR, FAIL, "unable to write raw data to file");
     } /* end if */
     else {
@@ -1889,7 +1874,7 @@ HDfprintf(stderr,"%s: mem_offset_arr[%Zu]=%Hu\n",FUNC,*mem_curr_seq,mem_offset_a
          * Lock the chunk, copy from application to chunk, then unlock the
          * chunk.
          */
-        if(chunk_max_nseq==1 && chunk_len_arr[0] == chunk_size)
+        if(chunk_max_nseq==1 && chunk_len_arr[0] == layout->chunk_size)
             relax = TRUE;
         else
             relax = FALSE;
@@ -2177,10 +2162,9 @@ H5F_istore_allocate(H5F_t *f, hid_t dxpl_id, const H5O_layout_t *layout,
      * Setup indice to go through all chunks. (Future improvement
      * should allocate only chunks that have no file space assigned yet.
      */
-    for (u=0, chunk_size=1; u<layout->ndims; u++) {
+    for (u=0; u<layout->ndims; u++)
         chunk_offset[u] = 0;
-        chunk_size *= layout->dim[u];
-    } /* end for */
+    chunk_size = layout->chunk_size;
 
     /* Check the dataset's fill-value status */
     if (H5P_is_fill_value_defined(&fill, &fill_status) < 0)
diff --git a/src/H5Olayout.c b/src/H5Olayout.c
index b9a41ec..9e92c3f 100644
--- a/src/H5Olayout.c
+++ b/src/H5Olayout.c
@@ -147,6 +147,11 @@ H5O_layout_decode(H5F_t *f, hid_t UNUSED dxpl_id, const uint8_t *p, H5O_shared_t
             p += mesg->size;
         }
     }
+    else if(mesg->type == H5D_CHUNKED) {
+        /* Compute chunk size */
+        for (u=0, mesg->chunk_size=1; u<mesg->ndims; u++)
+            mesg->chunk_size *= mesg->dim[u];
+    } /* end if */
 
     /* Set return value */
     ret_value=mesg;
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 70362ad..49cb08e 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -129,6 +129,7 @@ typedef struct H5O_layout_t {
     haddr_t	addr;			/*file address of data or B-tree     */ 
     unsigned	ndims;			/*num dimensions in stored data	     */
     hsize_t	dim[H5O_LAYOUT_NDIMS];	/*size of data or chunk in bytes     */
+    hsize_t     chunk_size;             /*size of chunk in bytes   */
     hbool_t     dirty;                  /*dirty flag for compact dataset     */ 
     size_t      size;                   /*size of compact dataset in bytes   */
     void        *buf;                   /*buffer for compact dataset         */