[ruby-core:61576] Re: [ruby-trunk - Feature #9425] [PATCH] st: use power-of-two sizes to avoid slow modulo ops

Can you test this
 + if (SYMBOL_P(a)) a = (a >> RUBY_SPECIAL_SHIFT) ^ (a >>
(RUBY_SPECIAL_SHIFT + 3)); /* 3=ID_SCOPE_SHIFT */


2014-03-18 13:02 GMT+04:00 Eric Wong <[e-mail]>:

> [e-mail] wrote:
> >       hash_aref_sym   1.000
>
> Lack of improvement here was disappointing since symbol keys are common,
> and this showed a regression on my x86 (32-bit) VMs.
>
> I tweaked rb_any_hash to be symbol-aware:
>
>         http://bogomips.org/ruby.git/patch?id=497ed6355
>
> 12-30% improvement on this test from trunk depending on CPU so far \o/
> (Phenom II X4 got 30%, newer/faster x86-64 CPUs show less speedup).
>
> I'm comfortable with improvements of this series on x86 VMs running on
> x86-64 (and of course native x86-64).
>
> Can anybody with real 32-bit hardware verify this series?  Not sure I
> can trust VM results; my remaining x86 hardware is on its last legs
> and showing occasional HW errors.
>
> git://80x24.org/ruby.git st-noprime-v4
>
>       st: use power-of-two sizes to avoid slow modulo ops
>       add hash benchmarks
>       st.c: tweak numhash to match common Ruby use cases
>       hash.c: improve symbol hash distribution
>