st.c: use power-of-two sizes to avoid slow modulo ops

* st.c (hash_pos): use bitwise AND to avoid slow modulo op
  (new_size): power-of-two sizes for hash_pos change
  (st_numhash): adjust for common keys due to lack of prime modulo
  [Feature #9425]
* hash.c (rb_any_hash): right shift for symbols
* benchmark/bm_hash_aref_miss.rb: added to show improvement
* benchmark/bm_hash_aref_sym_long.rb: ditto
* benchmark/bm_hash_aref_str.rb: ditto
* benchmark/bm_hash_aref_sym.rb: ditto
* benchmark/bm_hash_ident_num.rb: added to prevent regression
* benchmark/bm_hash_ident_obj.rb: ditto
* benchmark/bm_hash_ident_str.rb: ditto
* benchmark/bm_hash_ident_sym.rb: ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45384 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/hash.c b/hash.c
index 0023e84b1a..56917ed056 100644
--- a/hash.c
+++ b/hash.c
@@ -132,6 +132,7 @@ rb_any_hash(VALUE a)
 
     if (SPECIAL_CONST_P(a)) {
 	if (a == Qundef) return 0;
+	if (SYMBOL_P(a)) a >>= (RUBY_SPECIAL_SHIFT + 3); /* 3=ID_SCOPE_SHIFT */
 	hnum = rb_objid_hash((st_index_t)a);
     }
     else if (BUILTIN_TYPE(a) == T_STRING) {