This speeds up the hash function for dynamic symbols. [ruby-core:70129] [Bug #11396], nearly up to Ruby 2.1 levels
Power-of-two hash sizing [Feature #9425] speeds up cases where we
have a good hash, but this means we can no longer hide behind weak
hashes. Unfortunately, object IDs do not hash well, but we may
use the extra space in the RSymbol struct to memoize the hash value.
Further optimizations should be possible. For now, the st.c APIs
force us to calculate rb_str_hash redundantly at dsym registration.
symbol.h (struct RSymbol): add hashval field
symbol.c (dsymbol_alloc): setup hashval field once
symbol.h: memoize hashval for RSymbol
This speeds up the hash function for dynamic symbols.
[ruby-core:70129] [Bug #11396], nearly up to Ruby 2.1 levels
Power-of-two hash sizing [Feature #9425] speeds up cases where we
have a good hash, but this means we can no longer hide behind weak
hashes. Unfortunately, object IDs do not hash well, but we may
use the extra space in the RSymbol struct to memoize the hash value.
Further optimizations should be possible. For now, the st.c APIs
force us to calculate rb_str_hash redundantly at dsym registration.
Thanks to Bruno Escherl bruno@escherl.net for the bug report
[ruby-core:70129] [Bug #11396]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e