[ruby-core:72450] Re: Ruby 2.3.0-preview2 Released

[Eric Wong <normalperson@yhbt.net>]

OK.  I will try (maybe Zachary and others can help edit)...

Case dispatch is now optimized for all special constant literals
including nil, true, and false.  Previously, only literal strings,
symbols, integers and floats compiled to optimized case dispatch.
https://bugs.ruby-lang.org/issues/11769
(ed. I'm really not noticing this)

Instance variables on non-pure Ruby classes (T_DATA, T_FILE,
etc..) is less expensive to store than before.
https://bugs.ruby-lang.org/issues/11170

All accesses to members of big Struct objects are performed in
constant-time.  Previously, Struct elements beyond the first 10
10 elements used a linear scan.
https://bugs.ruby-lang.org/issues/10585

Fiddle::Function#call releases the GVL, allowing parallel execution
when calling 3rd-party libraries.  This may expose threading bugs
in existing code using Fiddle, but Fiddle usage is currently uncommon.
https://bugs.ruby-lang.org/issues/11607

The Set class got several speedps: r52591 and
https://bugs.ruby-lang.org/issues/10754


== Socket and I/O related changes:

All non-blocking I/O (including socket) methods allow
`exception: false' to suppress expensive and noisy exceptions
in common usage:
https://bugs.ruby-lang.org/issues/10532
https://bugs.ruby-lang.org/issues/11229

Furthermore, calling overhead of most of these keyword-using I/O
methods is reduced by avoiding the inefficient C API to parse keywords:
https://bugs.ruby-lang.org/issues/11339

Finally, the standard library is updated to use the improved
exception-free non-blocking I/O.  This has the additional
benefit of quieter $DEBUG output in addition to reducing expensive
exceptions.
https://bugs.ruby-lang.org/issues/11044

Additionally, the Socket#recv* methods allow an optional
destination buffer to reduce GC pressure, based on the
existing behavior of IO#read* methods.
https://bugs.ruby-lang.org/issues/11242



(Linux-only) waiting on a single FD anywhere in the stdlib no longer
uses select(2), making it immune to slowdowns with high-numbered FDs
https://bugs.ruby-lang.org/issues/11081
https://bugs.ruby-lang.org/issues/11377
(probably not worth mentioning since it's Linux-only)