[svn-r5536] Purpose:

    New feature.

Description:
    Added a "small data" block allocation mechanism to the library, similar to
    the mechanism used for allocating metadata currently.

    See the RFC for more details:
        http://hdf.ncsa.uiuc.edu/RFC/SmallData/SmallData.html

    This reduces the number of I/O operations which hit the disk for my test
    program from 19 to 15 (i.e. from 393 to 15, overall).

Platforms tested:
    Solaris 2.7 (arabica) w/FORTRAN and FreeBSD 4.5 (sleipnir) w/C++

16 files changed, 306 insertions, 208 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index ffa3ccf..1c3c174 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -171,6 +171,8 @@ Documentation
 New Features
 ============
 
+    * Added internal "small data" aggregation, which can reduce the number of
+      actual I/O calls made, improving performance.  QAK - 2002/06/05
     * Improved internal metadata aggregation, which can reduce the number of
       actual I/O calls made, improving performance.  Additionally, this can
       reduce the size of files produced.  QAK - 2002/06/04
diff --git a/src/H5F.c b/src/H5F.c
index 9e0860e..463f46e 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -193,8 +193,9 @@ H5F_init_interface(void)
     double          rdcc_w0             = H5F_ACS_PREEMPT_READ_CHUNKS_DEF;
     hsize_t         threshold           = H5F_ACS_ALIGN_THRHD_DEF;
     hsize_t         alignment           = H5F_ACS_ALIGN_DEF;
-    size_t          meta_block_size     = H5F_ACS_META_BLOCK_SIZE_DEF;
+    hsize_t         meta_block_size     = H5F_ACS_META_BLOCK_SIZE_DEF;
     size_t          sieve_buf_size      = H5F_ACS_SIEVE_BUF_SIZE_DEF;
+    hsize_t         sdata_block_size    = H5F_ACS_SDATA_BLOCK_SIZE_DEF;
     unsigned        gc_ref              = H5F_ACS_GARBG_COLCT_REF_DEF;
     hid_t           driver_id           = H5F_ACS_FILE_DRV_ID_DEF;
     void            *driver_info        = H5F_ACS_FILE_DRV_INFO_DEF;
@@ -358,6 +359,10 @@ H5F_init_interface(void)
         if(H5P_register(acs_pclass,H5F_ACS_SIEVE_BUF_SIZE_NAME,H5F_ACS_SIEVE_BUF_SIZE_SIZE, &sieve_buf_size,NULL,NULL,NULL,NULL,NULL,NULL)<0) 
              HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class"); 
 
+        /* Register the minimum "small data" allocation block size */
+        if(H5P_register(acs_pclass,H5F_ACS_SDATA_BLOCK_SIZE_NAME,H5F_ACS_SDATA_BLOCK_SIZE_SIZE, &sdata_block_size,NULL,NULL,NULL,NULL,NULL,NULL)<0) 
+             HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class"); 
+
         /* Register the garbage collection reference */
         if(H5P_register(acs_pclass,H5F_ACS_GARBG_COLCT_REF_NAME,H5F_ACS_GARBG_COLCT_REF_SIZE, &gc_ref,NULL,NULL,NULL,NULL,NULL,NULL)<0) 
              HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class"); 
@@ -850,6 +855,8 @@ H5Fget_access_plist(hid_t file_id)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set meta data cache size");
     if(H5P_set(new_plist, H5F_ACS_SIEVE_BUF_SIZE_NAME, &(f->shared->sieve_buf_size)) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't sieve buffer size");
+    if(H5P_set(new_plist, H5F_ACS_SDATA_BLOCK_SIZE_NAME, &(f->shared->lf->def_sdata_block_size)) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'small data' cache size");
 
     if(H5P_set(new_plist, H5F_ACS_FILE_DRV_ID_NAME, &(f->shared->lf->driver_id)) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file driver ID");
diff --git a/src/H5FD.c b/src/H5FD.c
index 55c8847..fe43159 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -775,6 +775,7 @@ H5FD_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     H5FD_t		*file=NULL;
     hid_t               driver_id = -1;
     size_t              meta_block_size=0;    
+    size_t              sdata_block_size=0;    
     H5P_genplist_t *plist;      /* Property list pointer */
     
     FUNC_ENTER_NOAPI(H5FD_open, NULL);
@@ -815,6 +816,9 @@ H5FD_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     if(H5P_get(plist, H5F_ACS_META_BLOCK_SIZE_NAME, &(meta_block_size)) < 0)
         HRETURN_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get meta data block size");
     file->def_meta_block_size = meta_block_size;
+    if(H5P_get(plist, H5F_ACS_SDATA_BLOCK_SIZE_NAME, &(sdata_block_size)) < 0)
+        HRETURN_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get 'small data' block size");
+    file->def_sdata_block_size = sdata_block_size;
     file->accum_loc = HADDR_UNDEF;
     if(H5P_get(plist, H5F_ACS_ALIGN_THRHD_NAME, &(file->threshold)) < 0)
         HRETURN_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get alignment threshold");
@@ -1420,72 +1424,144 @@ H5FD_alloc(H5FD_t *file, H5FD_mem_t type, hsize_t size)
     }
 #endif
 
-    /*
-     * If the metadata aggregation feature is enabled for this VFL driver,
-     * allocate "generic" metadata space and sub-allocate out of that, if
-     * possible.  Otherwise just allocate through H5FD_real_alloc()
-     */
-    /* Allocate all types of metadata out of the metadata block */
-    if((file->feature_flags&H5FD_FEAT_AGGREGATE_METADATA) && type!=H5FD_MEM_DRAW) {
-        /* Check if the space requested is larger than the space left in the block */
-        if(size>file->cur_meta_block_size) {
-            haddr_t new_meta;       /* Address for new metadata */
-
-            /* Check if the block asked for is too large for a metadata block */
-            if(size>=file->def_meta_block_size) {
-                /* Allocate more room for this new block the regular way */
-                new_meta=H5FD_real_alloc(file,type,size);
-
-                /* Check if the new metadata is at the end of the current metadata block */
-                if(file->eoma+file->cur_meta_block_size==new_meta) {
-                    /* Treat the allocation request as if the current metadata block
-                     * grew by the amount allocated and just update the eoma
-                     * address.  Don't bother updating the cur_meta_block_size
-                     * since it will just grow and shrink by the same amount.
-                     */
-                    ret_value=file->eoma;
-                    file->eoma+=size;
+    /* Handle metadata differently from "raw" data */
+    if(type!=H5FD_MEM_DRAW) {
+        /*
+         * If the metadata aggregation feature is enabled for this VFL driver,
+         * allocate "generic" metadata space and sub-allocate out of that, if
+         * possible.  Otherwise just allocate through H5FD_real_alloc()
+         */
+        /* Allocate all types of metadata out of the metadata block */
+        if(file->feature_flags&H5FD_FEAT_AGGREGATE_METADATA) {
+            /* Check if the space requested is larger than the space left in the block */
+            if(size>file->cur_meta_block_size) {
+                haddr_t new_meta;       /* Address for new metadata */
+
+                /* Check if the block asked for is too large for a metadata block */
+                if(size>=file->def_meta_block_size) {
+                    /* Allocate more room for this new block the regular way */
+                    new_meta=H5FD_real_alloc(file,type,size);
+
+                    /* Check if the new metadata is at the end of the current metadata block */
+                    if(file->eoma+file->cur_meta_block_size==new_meta) {
+                        /* Treat the allocation request as if the current metadata block
+                         * grew by the amount allocated and just update the eoma
+                         * address.  Don't bother updating the cur_meta_block_size
+                         * since it will just grow and shrink by the same amount.
+                         */
+                        ret_value=file->eoma;
+                        file->eoma+=size;
+                    } /* end if */
+                    else {
+                        /* Use the new metadata block for the space allocated */
+                        ret_value=new_meta;
+                    } /* end else */
                 } /* end if */
                 else {
-                    /* Use the new metadata block for the space allocated */
-                    ret_value=new_meta;
-                } /* end else */
-            } /* end if */
-            else {
-                /* Allocate another metadata block */
-                new_meta=H5FD_real_alloc(file,H5FD_MEM_DEFAULT,file->def_meta_block_size);
+                    /* Allocate another metadata block */
+                    new_meta=H5FD_real_alloc(file,H5FD_MEM_DEFAULT,file->def_meta_block_size);
 
-                /* Check if the new metadata is at the end of the current metadata block */
-                if(file->eoma+file->cur_meta_block_size==new_meta) {
-                    file->cur_meta_block_size+=file->def_meta_block_size;
-                } /* end if */
-                else {
-                    /*
-                     * Instead of just dropping the remainder of the block on the
-                     * floor and leaving the space in the file unused, we should
-                     * return this small piece of unused space to the free list
-                     * management. - QAK
-                     */
-                    file->eoma=new_meta;
-                    file->cur_meta_block_size=file->def_meta_block_size;
-                } /* end else */
+                    /* Check if the new metadata is at the end of the current metadata block */
+                    if(file->eoma+file->cur_meta_block_size==new_meta) {
+                        file->cur_meta_block_size+=file->def_meta_block_size;
+                    } /* end if */
+                    else {
+                        /*
+                         * Instead of just dropping the remainder of the block on the
+                         * floor and leaving the space in the file unused, we should
+                         * return this small piece of unused space to the free list
+                         * management. - QAK
+                         */
+                        file->eoma=new_meta;
+                        file->cur_meta_block_size=file->def_meta_block_size;
+                    } /* end else */
 
 
+                    /* Allocate space out of the metadata block */
+                    ret_value=file->eoma;
+                    file->cur_meta_block_size-=size;
+                    file->eoma+=size;
+                } /* end else */
+            } /* end if */
+            else {
                 /* Allocate space out of the metadata block */
                 ret_value=file->eoma;
                 file->cur_meta_block_size-=size;
                 file->eoma+=size;
             } /* end else */
         } /* end if */
-        else {
-            /* Allocate space out of the metadata block */
-            ret_value=file->eoma;
-            file->cur_meta_block_size-=size;
-            file->eoma+=size;
+        else { /* Allocate data the regular way */
+            ret_value=H5FD_real_alloc(file,type,size);
         } /* end else */
     } /* end if */
-    else { /* Allocate data the regular way */
-        ret_value=H5FD_real_alloc(file,type,size);
+    else { /* Allocate "raw" data */
+        /*
+         * If the "small data" aggregation feature is enabled for this VFL driver,
+         * allocate "small data" space and sub-allocate out of that, if
+         * possible.  Otherwise just allocate through H5FD_real_alloc()
+         */
+        if(file->feature_flags&H5FD_FEAT_AGGREGATE_SMALLDATA) {
+            /* Check if the space requested is larger than the space left in the block */
+            if(size>file->cur_sdata_block_size) {
+                haddr_t new_data;       /* Address for new raw data block */
+
+                /* Check if the block asked for is too large for the "small data" block */
+                if(size>=file->def_sdata_block_size) {
+                    /* Allocate more room for this new block the regular way */
+                    new_data=H5FD_real_alloc(file,type,size);
+
+                    /* Check if the new raw data is at the end of the current "small data" block */
+                    if(file->eosda+file->cur_sdata_block_size==new_data) {
+                        /* Treat the allocation request as if the current "small data"
+                         * block grew by the amount allocated and just update the
+                         * eosda address.  Don't bother updating the
+                         * cur_sdata_block_size since it will just grow and shrink by
+                         * the same amount.
+                         */
+                        ret_value=file->eosda;
+                        file->eosda+=size;
+                    } /* end if */
+                    else {
+                        /* Use the new "small data" block for the space allocated */
+                        ret_value=new_data;
+                    } /* end else */
+                } /* end if */
+                else {
+                    /* Allocate another "small data" block */
+                    new_data=H5FD_real_alloc(file,type,file->def_sdata_block_size);
+
+                    /* Check if the new raw data is at the end of the current "small data" block */
+                    if(file->eosda+file->cur_sdata_block_size==new_data) {
+                        file->cur_sdata_block_size+=file->def_sdata_block_size;
+                    } /* end if */
+                    else {
+                        /*
+                         * Instead of just dropping the remainder of the block on the
+                         * floor and leaving the space in the file unused, we should
+                         * return this small piece of unused space to the free list
+                         * management. - QAK
+                         */
+                        file->eosda=new_data;
+                        file->cur_sdata_block_size=file->def_sdata_block_size;
+                    } /* end else */
+
+
+                    /* Allocate space out of the "small data" block */
+                    ret_value=file->eosda;
+                    file->cur_sdata_block_size-=size;
+                    file->eosda+=size;
+                } /* end else */
+            } /* end if */
+            else {
+                /* Allocate space out of the "small data" block */
+                ret_value=file->eosda;
+                file->cur_sdata_block_size-=size;
+                file->eosda+=size;
+            } /* end else */
+        } /* end if */
+        else { /* Allocate data the regular way */
+            ret_value=H5FD_real_alloc(file,type,size);
+        } /* end else */
     } /* end else */
 
 done:
diff --git a/src/H5FDfamily.c b/src/H5FDfamily.c
index 4828d47..24a244d 100644
--- a/src/H5FDfamily.c
+++ b/src/H5FDfamily.c
@@ -682,6 +682,7 @@ H5FD_family_query(const H5FD_t UNUSED * _f, unsigned long *flags /* out */)
         *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
         *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDgass.c b/src/H5FDgass.c
index f5c3f2d..42b46b2 100644
--- a/src/H5FDgass.c
+++ b/src/H5FDgass.c
@@ -489,6 +489,7 @@ H5FD_gass_query(const UNUSED H5FD_t *_f, unsigned long *flags /* out */)
     if(flags) {
         *flags = 0;
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDlog.c b/src/H5FDlog.c
index 563f4f0..4036f9b 100644
--- a/src/H5FDlog.c
+++ b/src/H5FDlog.c
@@ -766,6 +766,7 @@ H5FD_log_query(const H5FD_t UNUSED * _f, unsigned long *flags /* out */)
         *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
         *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 69e2b49..0ec8db3 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -944,6 +944,7 @@ H5FD_mpio_query(const H5FD_t *_file, unsigned long *flags /* out */)
     if(flags) {
         *flags=0;
         *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     } /* end if */
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDmulti.c b/src/H5FDmulti.c
index 2e7045b..3d56cc9 100644
--- a/src/H5FDmulti.c
+++ b/src/H5FDmulti.c
@@ -1364,6 +1364,7 @@ H5FD_multi_query(const H5FD_t *_f, unsigned long *flags /* out */)
     if(flags) {
         *flags=0;
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     return(0);
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index 67256b5..49c89bc 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -100,6 +100,12 @@ typedef enum H5FD_mem_t {
      *  http://www.mcs.anl.gov/~thakur/papers/mpio-high-perf.ps.gz
      */
 #define H5FD_FEAT_DATA_SIEVE            0x00000004
+    /*
+     * Defining the H5FD_FEAT_AGGREGATE_SMALLDATA for a VFL driver means that
+     * the library will attempt to allocate a larger block for "small" raw data
+     * and then sub-allocate "small" raw data requests from that larger block.
+     */
+#define H5FD_FEAT_AGGREGATE_SMALLDATA   0x00000008
 	
 
 /* Forward declaration */
@@ -164,6 +170,11 @@ struct H5FD_t {
     hsize_t 			cur_meta_block_size;  /* Current size of metadata allocation region left */
     haddr_t 			eoma;       /*End of metadata allocated region*/
 
+    /* "Small data" aggregation fields */
+    hsize_t def_sdata_block_size;   /* "Small data" allocation block size (if aggregating "small data") */
+    hsize_t cur_sdata_block_size;   /* Current size of "small data" allocation region left */
+    haddr_t eosda;              /* End of "small data" allocated region */
+
     /* Metadata accumulator fields */
     unsigned char 		*meta_accum; /*Buffer to hold the accumulated metadata */
     haddr_t 			accum_loc;      /* File location (offset) of the accumulated metadata */
diff --git a/src/H5FDsec2.c b/src/H5FDsec2.c
index 03c4e29..25e5938 100644
--- a/src/H5FDsec2.c
+++ b/src/H5FDsec2.c
@@ -442,6 +442,7 @@ H5FD_sec2_query(const H5FD_t UNUSED * _f, unsigned long *flags /* out */)
         *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
         *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDsrb.c b/src/H5FDsrb.c
index f2a97de..1579af0 100644
--- a/src/H5FDsrb.c
+++ b/src/H5FDsrb.c
@@ -436,6 +436,7 @@ H5FD_srb_query(const UNUSED H5FD_t *_f, unsigned long *flags /* out */)
     if(flags) {
         *flags = 0;
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE(ret_value);
diff --git a/src/H5FDstdio.c b/src/H5FDstdio.c
index 387d736..2ae8398 100644
--- a/src/H5FDstdio.c
+++ b/src/H5FDstdio.c
@@ -471,6 +471,7 @@ H5FD_stdio_query(const H5FD_t *_f, unsigned long *flags /* out */)
         *flags|=H5FD_FEAT_AGGREGATE_METADATA; /* OK to aggregate metadata allocations */
         *flags|=H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags|=H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     return(0);
diff --git a/src/H5FDstream.c b/src/H5FDstream.c
index ac6e8dc..72cb7b8 100644
--- a/src/H5FDstream.c
+++ b/src/H5FDstream.c
@@ -907,6 +907,7 @@ H5FD_stream_query(const H5FD_t * UNUSED _f,
         *flags = 0;
         /* OK to perform data sieving for faster raw data reads & writes */
         *flags |= H5FD_FEAT_DATA_SIEVE;
+        *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
     FUNC_LEAVE (SUCCEED);
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 42af604..c18c331 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -253,66 +253,72 @@ __DLL__ size_t H5F_sizeof_size(const H5F_t *f);
 
 /* ========= File Access properties ============ */
 /* Definitions for size of meta data cache(elements) */
-#define H5F_ACS_META_CACHE_SIZE_NAME           "mdc_nelmts"
-#define H5F_ACS_META_CACHE_SIZE_SIZE           sizeof(int)
-#define H5F_ACS_META_CACHE_SIZE_DEF            H5AC_NSLOTS
+#define H5F_ACS_META_CACHE_SIZE_NAME            "mdc_nelmts"
+#define H5F_ACS_META_CACHE_SIZE_SIZE            sizeof(int)
+#define H5F_ACS_META_CACHE_SIZE_DEF             H5AC_NSLOTS
 
 /* Definitions for size of raw data chunk cache(elements) */
-#define H5F_ACS_DATA_CACHE_ELMT_SIZE_NAME      "rdcc_nelmts"
-#define H5F_ACS_DATA_CACHE_ELMT_SIZE_SIZE      sizeof(size_t)
-#define H5F_ACS_DATA_CACHE_ELMT_SIZE_DEF       521
+#define H5F_ACS_DATA_CACHE_ELMT_SIZE_NAME       "rdcc_nelmts"
+#define H5F_ACS_DATA_CACHE_ELMT_SIZE_SIZE       sizeof(size_t)
+#define H5F_ACS_DATA_CACHE_ELMT_SIZE_DEF        521
 
 /* Definition for size of raw data chunk cache(bytes) */
-#define H5F_ACS_DATA_CACHE_BYTE_SIZE_NAME      "rdcc_nbytes"
-#define H5F_ACS_DATA_CACHE_BYTE_SIZE_SIZE      sizeof(size_t)
-#define H5F_ACS_DATA_CACHE_BYTE_SIZE_DEF       1024*1024
+#define H5F_ACS_DATA_CACHE_BYTE_SIZE_NAME       "rdcc_nbytes"
+#define H5F_ACS_DATA_CACHE_BYTE_SIZE_SIZE       sizeof(size_t)
+#define H5F_ACS_DATA_CACHE_BYTE_SIZE_DEF        1024*1024
 
 /* Definition for preemption read chunks first */
-#define H5F_ACS_PREEMPT_READ_CHUNKS_NAME       "rdcc_w0"
-#define H5F_ACS_PREEMPT_READ_CHUNKS_SIZE       sizeof(double)
-#define H5F_ACS_PREEMPT_READ_CHUNKS_DEF        0.75  
+#define H5F_ACS_PREEMPT_READ_CHUNKS_NAME        "rdcc_w0"
+#define H5F_ACS_PREEMPT_READ_CHUNKS_SIZE        sizeof(double)
+#define H5F_ACS_PREEMPT_READ_CHUNKS_DEF         0.75  
 
 /* Definition for threshold for alignment */
-#define H5F_ACS_ALIGN_THRHD_NAME               "threshold"
-#define H5F_ACS_ALIGN_THRHD_SIZE               sizeof(hsize_t)
-#define H5F_ACS_ALIGN_THRHD_DEF                1
+#define H5F_ACS_ALIGN_THRHD_NAME                "threshold"
+#define H5F_ACS_ALIGN_THRHD_SIZE                sizeof(hsize_t)
+#define H5F_ACS_ALIGN_THRHD_DEF                 1
 
 /* Definition for alignment */
-#define H5F_ACS_ALIGN_NAME                     "align"
-#define H5F_ACS_ALIGN_SIZE                     sizeof(hsize_t)
-#define H5F_ACS_ALIGN_DEF                      1
+#define H5F_ACS_ALIGN_NAME                      "align"
+#define H5F_ACS_ALIGN_SIZE                      sizeof(hsize_t)
+#define H5F_ACS_ALIGN_DEF                       1
 
-/* Definition for minimum metadata allocation block size(when
+/* Definition for minimum metadata allocation block size (when
    aggregating metadata allocations. */
-#define H5F_ACS_META_BLOCK_SIZE_NAME           "meta_block_size"
-#define H5F_ACS_META_BLOCK_SIZE_SIZE           sizeof(size_t)
-#define H5F_ACS_META_BLOCK_SIZE_DEF            2048
+#define H5F_ACS_META_BLOCK_SIZE_NAME            "meta_block_size"
+#define H5F_ACS_META_BLOCK_SIZE_SIZE            sizeof(hsize_t)
+#define H5F_ACS_META_BLOCK_SIZE_DEF             2048
 
 /* Definition for maximum sieve buffer size (when data sieving 
    is allowed by file driver */
-#define H5F_ACS_SIEVE_BUF_SIZE_NAME         "sieve_buf_size"
-#define H5F_ACS_SIEVE_BUF_SIZE_SIZE         sizeof(size_t)
-#define H5F_ACS_SIEVE_BUF_SIZE_DEF          64*1024
+#define H5F_ACS_SIEVE_BUF_SIZE_NAME             "sieve_buf_size"
+#define H5F_ACS_SIEVE_BUF_SIZE_SIZE             sizeof(size_t)
+#define H5F_ACS_SIEVE_BUF_SIZE_DEF              64*1024
+
+/* Definition for minimum "small data" allocation block size (when
+   aggregating "small" raw data allocations. */
+#define H5F_ACS_SDATA_BLOCK_SIZE_NAME           "sdata_block_size"
+#define H5F_ACS_SDATA_BLOCK_SIZE_SIZE           sizeof(hsize_t)
+#define H5F_ACS_SDATA_BLOCK_SIZE_DEF            2048
 
 /* Definition for garbage-collect references */
-#define H5F_ACS_GARBG_COLCT_REF_NAME           "gc_ref"
-#define H5F_ACS_GARBG_COLCT_REF_SIZE           sizeof(unsigned)
-#define H5F_ACS_GARBG_COLCT_REF_DEF            0
+#define H5F_ACS_GARBG_COLCT_REF_NAME            "gc_ref"
+#define H5F_ACS_GARBG_COLCT_REF_SIZE            sizeof(unsigned)
+#define H5F_ACS_GARBG_COLCT_REF_DEF             0
 
 /* Definition for file driver ID */
-#define H5F_ACS_FILE_DRV_ID_NAME               "driver_id"
-#define H5F_ACS_FILE_DRV_ID_SIZE               sizeof(hid_t)
-#define H5F_ACS_FILE_DRV_ID_DEF                H5FD_SEC2
+#define H5F_ACS_FILE_DRV_ID_NAME                "driver_id"
+#define H5F_ACS_FILE_DRV_ID_SIZE                sizeof(hid_t)
+#define H5F_ACS_FILE_DRV_ID_DEF                 H5FD_SEC2
 
 /* Definition for file driver info */
-#define H5F_ACS_FILE_DRV_INFO_NAME             "driver_info"
-#define H5F_ACS_FILE_DRV_INFO_SIZE             sizeof(void*)
-#define H5F_ACS_FILE_DRV_INFO_DEF              NULL
+#define H5F_ACS_FILE_DRV_INFO_NAME              "driver_info"
+#define H5F_ACS_FILE_DRV_INFO_SIZE              sizeof(void*)
+#define H5F_ACS_FILE_DRV_INFO_DEF               NULL
 
 /* Definition for file close degree */
-#define H5F_CLOSE_DEGREE_NAME		       "close_degree"
-#define H5F_CLOSE_DEGREE_SIZE		       sizeof(H5F_close_degree_t)
-#define H5F_CLOSE_DEGREE_DEF		       H5F_CLOSE_DEFAULT
+#define H5F_CLOSE_DEGREE_NAME		        "close_degree"
+#define H5F_CLOSE_DEGREE_SIZE		        sizeof(H5F_close_degree_t)
+#define H5F_CLOSE_DEGREE_DEF		        H5F_CLOSE_DEFAULT
 
 /* ======================== File Mount properties ====================*/
 /* Definition for whether absolute symlinks local to file. */
diff --git a/src/H5P.c b/src/H5P.c
index 8f88801..5efdabc 100644
--- a/src/H5P.c
+++ b/src/H5P.c
@@ -3987,113 +3987,6 @@ done:
     FUNC_LEAVE(ret_value);
 }
 
-#ifdef H5_WANT_H5_V1_4_COMPAT
-
-/*-------------------------------------------------------------------------
- * Function:	H5Pset_meta_block_size
- *
- * Purpose:	Sets the minimum size of metadata block allocations when
- *      the H5FD_FEAT_AGGREGATE_METADATA is set by a VFL driver.
- *      Each "raw" metadata block is allocated to be this size and then
- *      specific pieces of metadata (object headers, local heaps, B-trees, etc)
- *      are sub-allocated from this block.
- *      
- *		The default value is set to 2048 (bytes), indicating that metadata
- *      will be attempted to be bunched together in (at least) 2K blocks in
- *      the file.  Setting the value to 0 with this API function will
- *      turn off the metadata aggregation, even if the VFL driver attempts to
- *      use that strategy.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *              Friday, August 25, 2000
- *
- * Modifications:
- *
- *		Raymond Lu
- *		Tuesday, Oct 23, 2001
- *		Changed the file access list to the new generic property 
- *		list. 
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5Pset_meta_block_size(hid_t plist_id, hsize_t _size)
-{
-    H5P_genplist_t *plist;      /* Property list pointer */
-    size_t size=(size_t)_size;  /* Work around parameter size difference */
-    herr_t ret_value=SUCCEED;   /* return value */
-
-    FUNC_ENTER_API(H5Pset_meta_block_size, FAIL);
-    H5TRACE2("e","ih",plist_id,_size);
-
-    /* Check args */
-    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list");  
-
-    /* Get the plist structure */
-    if(NULL == (plist = H5I_object(plist_id)))
-        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
-
-    /* Set values */
-    if(H5P_set(plist, H5F_ACS_META_BLOCK_SIZE_NAME, &size) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set meta data block size");
-
-done:
-    FUNC_LEAVE(ret_value);
-}
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5Pget_meta_block_size
- *
- * Purpose:	Returns the current settings for the metadata block allocation
- *      property from a file access property list.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *              Friday, August 29, 2000
- *
- * Modifications:
- *
- *		Raymond Lu 
- * 		Tuesday, Oct 23, 2001
- *		Changed the file access list to the new generic property 
- *		list.
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5Pget_meta_block_size(hid_t plist_id, hsize_t *_size/*out*/)
-{
-    H5P_genplist_t *plist;      /* Property list pointer */
-    size_t size;  /* Work around parameter size difference */
-    herr_t ret_value=SUCCEED;   /* return value */
-
-    FUNC_ENTER_API(H5Pget_meta_block_size, FAIL);
-    H5TRACE2("e","ix",plist_id,_size);
-
-    /* Check args */
-    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list");  
-
-    /* Get the plist structure */
-    if(NULL == (plist = H5I_object(plist_id)))
-        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
-
-    /* Get values */
-    if (_size) {
-        if(H5P_get(plist, H5F_ACS_META_BLOCK_SIZE_NAME, &size) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get meta data block size");
-        *_size=size;
-    } /* end if */
-
-done:
-    FUNC_LEAVE(ret_value);
-}
-#else /* H5_WANT_H5_V1_4_COMPAT */
 
 /*-------------------------------------------------------------------------
  * Function:	H5Pset_meta_block_size
@@ -4125,13 +4018,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_meta_block_size(hid_t plist_id, size_t size)
+H5Pset_meta_block_size(hid_t plist_id, hsize_t size)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t ret_value=SUCCEED;   /* return value */
 
     FUNC_ENTER_API(H5Pset_meta_block_size, FAIL);
-    H5TRACE2("e","iz",plist_id,size);
+    H5TRACE2("e","ih",plist_id,size);
 
     /* Check args */
     if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
@@ -4171,7 +4064,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_meta_block_size(hid_t plist_id, size_t *size/*out*/)
+H5Pget_meta_block_size(hid_t plist_id, hsize_t *size/*out*/)
 {
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t ret_value=SUCCEED;   /* return value */
@@ -4188,14 +4081,14 @@ H5Pget_meta_block_size(hid_t plist_id, size_t *size/*out*/)
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
     /* Get values */
-    if (size)
+    if (size) {
         if(H5P_get(plist, H5F_ACS_META_BLOCK_SIZE_NAME, size) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get meta data block size");
+    } /* end if */
 
 done:
     FUNC_LEAVE(ret_value);
 }
-#endif /* H5_WANT_H5_V1_4_COMPAT */
 
 #ifdef H5_WANT_H5_V1_4_COMPAT
 
@@ -4499,6 +4392,101 @@ done:
     FUNC_LEAVE(ret_value);
 } /* end H5Pget_hyper_vector_size() */
 
+#ifdef LATER
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pset_small_data_block_size
+ *
+ * Purpose:	Sets the minimum size of "small" raw data block allocations
+ *      when the H5FD_FEAT_AGGREGATE_SMALLDATA is set by a VFL driver.
+ *      Each "small" raw data block is allocated to be this size and then
+ *      pieces of raw data which are small enough to fit are sub-allocated from
+ *      this block.
+ *      
+ *	The default value is set to 2048 (bytes), indicating that raw data
+ *      smaller than this value will be attempted to be bunched together in (at
+ *      least) 2K blocks in the file.  Setting the value to 0 with this API
+ *      function will turn off the "small" raw data aggregation, even if the
+ *      VFL driver attempts to use that strategy.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Wednesday, June 5, 2002
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_small_data_block_size(hid_t plist_id, hsize_t size)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value=SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(H5Pset_small_data_block_size, FAIL);
+    H5TRACE2("e","ih",plist_id,size);
+
+    /* Check args */
+    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list");  
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5I_object(plist_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+
+    /* Set values */
+    if(H5P_set(plist, H5F_ACS_SDATA_BLOCK_SIZE_NAME, &size) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set 'small data' block size");
+
+done:
+    FUNC_LEAVE(ret_value);
+} /* end H5Pset_small_data_block_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pget_small_data_block_size
+ *
+ * Purpose:	Returns the current settings for the "small" raw data block
+ *      allocation property from a file access property list.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Wednesday, June 5, 2002
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_small_data_block_size(hid_t plist_id, hsize_t *size/*out*/)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value=SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(H5Pget_small_data_block_size, FAIL);
+    H5TRACE2("e","ix",plist_id,size);
+
+    /* Check args */
+    if(TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list");  
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5I_object(plist_id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
+
+    /* Get values */
+    if (size) {
+        if(H5P_get(plist, H5F_ACS_META_BLOCK_SIZE_NAME, size) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get 'small data' block size");
+    } /* end if */
+
+done:
+    FUNC_LEAVE(ret_value);
+} /* end H5Pget_small_data_block_size() */
+#endif /* LATER */
+
 
 /*--------------------------------------------------------------------------
  NAME
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index d50f268..ab15cbd 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -251,13 +251,8 @@ __DLL__ herr_t H5Pget_vlen_mem_manager(hid_t plist_id,
                                        void **alloc_info,
                                        H5MM_free_t *free_func,
                                        void **free_info);
-#ifdef H5_WANT_H5_V1_4_COMPAT
 __DLL__ herr_t H5Pset_meta_block_size(hid_t fapl_id, hsize_t size);
 __DLL__ herr_t H5Pget_meta_block_size(hid_t fapl_id, hsize_t *size/*out*/);
-#else /* H5_WANT_H5_V1_4_COMPAT */
-__DLL__ herr_t H5Pset_meta_block_size(hid_t fapl_id, size_t size);
-__DLL__ herr_t H5Pget_meta_block_size(hid_t fapl_id, size_t *size/*out*/);
-#endif /* H5_WANT_H5_V1_4_COMPAT */
 #ifdef H5_WANT_H5_V1_4_COMPAT
 __DLL__ herr_t H5Pset_sieve_buf_size(hid_t fapl_id, hsize_t size);
 __DLL__ herr_t H5Pget_sieve_buf_size(hid_t fapl_id, hsize_t *size/*out*/);
@@ -267,6 +262,10 @@ __DLL__ herr_t H5Pget_sieve_buf_size(hid_t fapl_id, size_t *size/*out*/);
 #endif /* H5_WANT_H5_V1_4_COMPAT */
 __DLL__ herr_t H5Pset_hyper_vector_size(hid_t fapl_id, size_t size);
 __DLL__ herr_t H5Pget_hyper_vector_size(hid_t fapl_id, size_t *size/*out*/);
+#ifdef LATER
+__DLL__ herr_t H5Pset_small_data_block_size(hid_t fapl_id, hsize_t size);
+__DLL__ herr_t H5Pget_small_data_block_size(hid_t fapl_id, hsize_t *size/*out*/);
+#endif /* LATER */
 
 #ifdef __cplusplus
 }