Use prime numbers for hash sizes

runtime/src/kmp.h

@@ -2248,10 +2248,9 @@ struct kmp_dephash_entry {
 typedef struct kmp_dephash {
   kmp_dephash_entry_t **buckets;
   size_t size;
+  size_t generation;
   kmp_uint32 nelements;
-#ifdef KMP_DEBUG
   kmp_uint32 nconflicts;
-#endif
 } kmp_dephash_t;
 
 #if OMP_50_ENABLED

runtime/src/kmp_taskdeps.cpp

@@ -56,6 +56,8 @@ static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) {
 
 enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 };
 
+size_t sizes[] = { 997, 2003, 4001, 8191, 16001, 32003, 64007, 131071, 270029 };
+
 static inline kmp_int32 __kmp_dephash_hash(kmp_intptr_t addr, size_t hsize) {
   // TODO alternate to try: set = (((Addr64)(addrUsefulBits * 9.618)) %
   // m_num_sets );
@@ -66,7 +68,14 @@ static kmp_dephash_t *__kmp_dephash_extend(kmp_info_t *thread,
                                            kmp_dephash_t *current_dephash) {
   kmp_dephash_t *h;
 
+  size_t gen = current_dephash->generation + 1;
+#if 1
+  if (gen >= 9)
+    return current_dephash;
+  size_t new_size = sizes[gen];
+#else
   size_t new_size = current_dephash->size * 2;
+#endif
 
   kmp_int32 size_to_allocate =
       new_size * sizeof(kmp_dephash_entry_t *) + sizeof(kmp_dephash_t);
@@ -80,15 +89,21 @@ static kmp_dephash_t *__kmp_dephash_extend(kmp_info_t *thread,
   h->size = new_size;
   h->nelements = current_dephash->nelements;
   h->buckets = (kmp_dephash_entry **)(h + 1);
+  h->generation = gen;
 
   // insert existing elements in the new table
   for (size_t i = 0; i < current_dephash->size; i++) {
     kmp_dephash_entry_t *next;
+    int nelems = 0;
     for (kmp_dephash_entry_t *entry = current_dephash->buckets[i]; entry; entry = next) {
       next = entry->next_in_bucket;
       // Compute the new hash using the new size, and insert the entry in
       // the new bucket.
       kmp_int32 new_bucket = __kmp_dephash_hash(entry->addr, h->size);
+      nelems++;
+      if (entry->next_in_bucket) {
+        h->nconflicts++;
+      }
       entry->next_in_bucket = h->buckets[new_bucket];
       h->buckets[new_bucket] = entry;
     }
@@ -125,10 +140,9 @@ static kmp_dephash_t *__kmp_dephash_create(kmp_info_t *thread,
 #endif
   h->size = h_size;
 
+  h->generation = 0;
   h->nelements = 0;
-#ifdef KMP_DEBUG
   h->nconflicts = 0;
-#endif
   h->buckets = (kmp_dephash_entry **)(h + 1);
 
   for (size_t i = 0; i < h_size; i++)
@@ -144,7 +158,8 @@ static kmp_dephash_entry *
 __kmp_dephash_find(kmp_info_t *thread, kmp_dephash_t **hash, kmp_intptr_t addr) {
   kmp_dephash_t *h = *hash;
   if (h->nelements != 0
-      && h->nelements >= h->size) {
+      && h->nconflicts/h->size >= 1) {
+      //&& h->nelements >= h->size) {
     //fprintf(stderr, "Resizing hashtable\n");
     *hash = __kmp_dephash_extend(thread, h);
     h = *hash;
@@ -174,10 +189,8 @@ __kmp_dephash_find(kmp_info_t *thread, kmp_dephash_t **hash, kmp_intptr_t addr)
     entry->next_in_bucket = h->buckets[bucket];
     h->buckets[bucket] = entry;
     h->nelements++;
-#ifdef KMP_DEBUG
     if (entry->next_in_bucket)
       h->nconflicts++;
-#endif
   }
   return entry;
 }