Improve spec. reading superblock into cache (a little) by using v2 size

Instead of reading the absolute minimal possible, use the likely value of a v2+ superblock w/8-byte addresses & lengths. Signed-off-by: Quincey Koziol <[email protected]>
HDFGroup · May 15, 2024 · 3dce0d7 · 3dce0d7
1 parent 6203a44
commit 3dce0d7
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Showing 3 changed files with 7 additions and 4 deletions.
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
@@ -131,6 +131,11 @@
     (H5F_SUPERBLOCK_FIXED_SIZE +                                                                             \
      H5F_SUPERBLOCK_VARLEN_SIZE((s)->super_vers, (s)->sizeof_addr, (s)->sizeof_size))
 
+/* Optimistic read size for superblock */
+/* Size of a v2+ superblock, w/8-byte addresses & lengths */
+#define H5F_SUPERBLOCK_SPEC_READ_SIZE \
+    (H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_VARLEN_SIZE(2, 8, 8))
+
 /* For superblock version 0 & 1:
    Offset to the file consistency flags (status_flags) in the superblock (excluding H5F_SUPERBLOCK_FIXED_SIZE)
  */

diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
@@ -416,8 +416,7 @@ H5F__super_read(H5F_t *f, H5P_genplist_t *fa_plist, bool initial_read)
         HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "can't get property list");
 
     /* Make certain we can read the fixed-size portion of the superblock */
-    if (H5F__set_eoa(f, H5FD_MEM_SUPER,
-                     (haddr_t)(H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE)) < 0)
+    if (H5F__set_eoa(f, H5FD_MEM_SUPER, (haddr_t)H5F_SUPERBLOCK_SPEC_READ_SIZE) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "set end of space allocation request failed");
 
     /* Set up the user data for cache callbacks */

diff --git a/src/H5Fsuper_cache.c b/src/H5Fsuper_cache.c
@@ -306,8 +306,7 @@ H5F__cache_superblock_get_initial_load_size(void H5_ATTR_UNUSED *_udata, size_t
     assert(image_len);
 
     /* Set the initial image length size */
-    *image_len = H5F_SUPERBLOCK_FIXED_SIZE + /* Fixed size of superblock */
-                 H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE;
+    *image_len = H5F_SUPERBLOCK_SPEC_READ_SIZE;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5F__cache_superblock_get_initial_load_size() */