diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | benchmark/bm_hash_shift_u16.rb | 10 | ||||
| -rw-r--r-- | benchmark/bm_hash_shift_u24.rb | 10 | ||||
| -rw-r--r-- | benchmark/bm_hash_shift_u32.rb | 10 | ||||
| -rw-r--r-- | hash.c | 4 |
5 files changed, 37 insertions, 2 deletions
@@ -1,3 +1,8 @@ +Fri Dec 11 16:48:57 2015 Eric Wong <e@80x24.org> + + * hash.c (rb_num_hash_start): avoid pathological behavior + [ruby-core:72028] [Feature #11405] + Fri Dec 11 11:58:46 2015 SHIBATA Hiroshi <hsbt@ruby-lang.org> * NEWS: Mentioned rubygems-2.5.1 diff --git a/benchmark/bm_hash_shift_u16.rb b/benchmark/bm_hash_shift_u16.rb new file mode 100644 index 0000000000..ec800d0342 --- /dev/null +++ b/benchmark/bm_hash_shift_u16.rb @@ -0,0 +1,10 @@ +h = {} + +(16384..65536).each do |i| + h[i] = nil +end + +300000.times do + k, v = h.shift + h[k] = v +end diff --git a/benchmark/bm_hash_shift_u24.rb b/benchmark/bm_hash_shift_u24.rb new file mode 100644 index 0000000000..de4e0fa696 --- /dev/null +++ b/benchmark/bm_hash_shift_u24.rb @@ -0,0 +1,10 @@ +h = {} + +(0xff4000..0xffffff).each do |i| + h[i] = nil +end + +300000.times do + k, v = h.shift + h[k] = v +end diff --git a/benchmark/bm_hash_shift_u32.rb b/benchmark/bm_hash_shift_u32.rb new file mode 100644 index 0000000000..656aa55583 --- /dev/null +++ b/benchmark/bm_hash_shift_u32.rb @@ -0,0 +1,10 @@ +h = {} + +(0xffff4000..0xffffffff).each do |i| + h[i] = nil +end + +300000.times do + k, v = h.shift + h[k] = v +end @@ -191,11 +191,11 @@ rb_num_hash_start(st_index_t n) * - (n >> (RUBY_SPECIAL_SHIFT+3)) was added to make symbols hash well, * n.b.: +3 to remove most ID scope, +1 worked well initially, too * n.b.: +1 (instead of 3) worked well initially, too - * - (n << 3) was finally added to avoid losing bits for fixnums + * - (n << 16) was finally added to avoid losing bits for fixnums * - avoid expensive modulo instructions, it is currently only * shifts and bitmask operations. */ - return (n >> (RUBY_SPECIAL_SHIFT + 3) | (n << 3)) ^ (n >> 3); + return (n >> (RUBY_SPECIAL_SHIFT + 3) ^ (n << 16)) ^ (n >> 3); } long |