[svn-r16480] Purpose: Improve chunk cache

Description:
The meaning of the "nbytes" field in H5D_rdcc_t was not clear, and some places
assumed it was the maximum size of the chunk cache, while some assumed it was
the current size of the chunk cache.  The end result was that only 1 chunk could
be held in cache at a time.  This field has been replaced by "nbytes_max" and
"nbytes_used".  Performance of cached I/O should improve greatly.

Tested: jam, smirom (h5committest)

1 files changed, 14 insertions, 14 deletions

diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index 1c27ede..a64f1ef 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -1396,7 +1396,7 @@ H5D_chunk_cacheable(const H5D_io_info_t *io_info)
              * cache, just write the data to it directly.
              */
             H5_CHECK_OVERFLOW(dataset->shared->layout.u.chunk.size, uint32_t, size_t);
-            if((size_t)dataset->shared->layout.u.chunk.size > dataset->shared->cache.chunk.nbytes)
+            if((size_t)dataset->shared->layout.u.chunk.size > dataset->shared->cache.chunk.nbytes_max)
                 ret_value = FALSE;
             else
                 ret_value = TRUE;
@@ -1848,19 +1848,19 @@ H5D_chunk_init(H5F_t *f, hid_t dapl_id, hid_t dxpl_id, const H5D_t *dset)
     if(rdcc->nslots == H5D_CHUNK_CACHE_NSLOTS_DEFAULT)
         rdcc->nslots = H5F_RDCC_NSLOTS(f);
 
-    if(H5P_get(dapl, H5D_ACS_DATA_CACHE_BYTE_SIZE_NAME, &rdcc->nbytes) < 0)
+    if(H5P_get(dapl, H5D_ACS_DATA_CACHE_BYTE_SIZE_NAME, &rdcc->nbytes_max) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get data cache byte size");
-    if(rdcc->nbytes == H5D_CHUNK_CACHE_NBYTES_DEFAULT)
-        rdcc->nbytes = H5F_RDCC_NBYTES(f);
+    if(rdcc->nbytes_max == H5D_CHUNK_CACHE_NBYTES_DEFAULT)
+        rdcc->nbytes_max = H5F_RDCC_NBYTES(f);
 
     if(H5P_get(dapl, H5D_ACS_PREEMPT_READ_CHUNKS_NAME, &rdcc->w0) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get preempt read chunks");
     if(rdcc->w0 < 0)
         rdcc->w0 = H5F_RDCC_W0(f);
 
-    /* If nbytes or nslots is 0, set them both to 0 and avoid allocating space */
-    if(!rdcc->nbytes || !rdcc->nslots)
-        rdcc->nbytes = rdcc->nslots = 0;
+    /* If nbytes_max or nslots is 0, set them both to 0 and avoid allocating space */
+    if(!rdcc->nbytes_max || !rdcc->nslots)
+        rdcc->nbytes_max = rdcc->nslots = 0;
     else {
         rdcc->slot = H5FL_SEQ_CALLOC(H5D_rdcc_ent_ptr_t, rdcc->nslots);
         if(NULL == rdcc->slot)
@@ -2135,7 +2135,7 @@ H5D_chunk_get_info(const H5D_t *dset, hid_t dxpl_id, const hsize_t *chunk_offset
 
         /* The same condition check as H5D_chunk_cacheable. */
         if(dset->shared->dcpl_cache.pline.nused || 
-            ((size_t)dset->shared->layout.u.chunk.size <= dset->shared->cache.chunk.nbytes))
+            ((size_t)dset->shared->layout.u.chunk.size <= dset->shared->cache.chunk.nbytes_max))
             /* Cache the information retrieved */
             H5D_chunk_cinfo_cache_update(&dset->shared->cache.chunk.last, udata);
     } /* end if */
@@ -2345,7 +2345,7 @@ H5D_chunk_cache_evict(const H5D_t *dset, hid_t dxpl_id, const H5D_dxpl_cache_t *
     /* Remove from cache */
     rdcc->slot[ent->idx] = NULL;
     ent->idx = UINT_MAX;
-    rdcc->nbytes -= ent->chunk_size;
+    rdcc->nbytes_used -= ent->chunk_size;
     --rdcc->nused;
 
     /* Free */
@@ -2375,7 +2375,7 @@ H5D_chunk_cache_prune(const H5D_t *dset, hid_t dxpl_id,
     const H5D_dxpl_cache_t *dxpl_cache, size_t size)
 {
     const H5D_rdcc_t	*rdcc = &(dset->shared->cache.chunk);
-    size_t		total = rdcc->nbytes;
+    size_t		total = rdcc->nbytes_max;
     const int		nmeth = 2;	/*number of methods		*/
     int		        w[1];		/*weighting as an interval	*/
     H5D_rdcc_ent_t	*p[2], *cur;	/*list pointers			*/
@@ -2399,7 +2399,7 @@ H5D_chunk_cache_prune(const H5D_t *dset, hid_t dxpl_id,
     p[0] = rdcc->head;
     p[1] = NULL;
 
-    while((p[0] || p[1]) && (rdcc->nbytes + size) > total) {
+    while((p[0] || p[1]) && (rdcc->nbytes_used + size) > total) {
         int i;          /* Local index variable */
 
 	/* Introduce new pointers */
@@ -2412,7 +2412,7 @@ H5D_chunk_cache_prune(const H5D_t *dset, hid_t dxpl_id,
             n[i] = p[i] ? p[i]->next : NULL;
 
 	/* Give each method a chance */
-	for(i = 0; i < nmeth && (rdcc->nbytes + size) > total; i++) {
+	for(i = 0; i < nmeth && (rdcc->nbytes_used + size) > total; i++) {
 	    if(0 == i && p[0] && !p[0]->locked &&
                     ((0 == p[0]->rd_count && 0 == p[0]->wr_count) ||
                      (0 == p[0]->rd_count && p[0]->chunk_size == p[0]->wr_count) ||
@@ -2632,7 +2632,7 @@ H5D_chunk_lock(const H5D_io_info_t *io_info, H5D_chunk_ud_t *udata,
     } /* end else */
     HDassert(found || chunk_size > 0);
 
-    if(!found && rdcc->nslots > 0 && chunk_size <= rdcc->nbytes &&
+    if(!found && rdcc->nslots > 0 && chunk_size <= rdcc->nbytes_max &&
             (!ent || !ent->locked)) {
         /*
          * Add the chunk to the cache only if the slot is not already locked.
@@ -2662,7 +2662,7 @@ H5D_chunk_lock(const H5D_io_info_t *io_info, H5D_chunk_ud_t *udata,
         HDassert(NULL == rdcc->slot[idx]);
         rdcc->slot[idx] = ent;
         ent->idx = idx;
-        rdcc->nbytes += chunk_size;
+        rdcc->nbytes_used += chunk_size;
         rdcc->nused++;
 
         /* Add it to the linked list */