[MacRuby] #1157: String#slice is an order of magnitude slower on MacRuby compared to 1.9.2-p136

[MacRuby]

#1157: String#slice is an order of magnitude slower on MacRuby compared to
1.9.2-p136
------------------------------------+---------------------------------------
 Reporter:  mrada@…                 |       Owner:  lsansonetti@…        
     Type:  defect                  |      Status:  new                  
 Priority:  blocker                 |   Milestone:                       
Component:  MacRuby                 |    Keywords:                       
------------------------------------+---------------------------------------

Comment(by watson1978@…):

 When duplicates String or slices String with full range, there is no
 memory allocation in CRuby19.

 - Duplicated String shared pointer to source string's bytes.
 - If changes duplicated string, memory allocates and copies source string,
 and then, changes string.

 I wrote a patch. https://gist.github.com/1686573

 {{{
 $ ruby19 -v bm_string.rb
 ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin11.2.0]
                 user     system      total        real
 dup         0.060000   0.010000   0.070000 (  0.078929)
 [0..-1]     0.000000   0.000000   0.000000 (  0.001177)
 [0..-2]     0.060000   0.060000   0.120000 (  0.110514)


 ** Before

 $ macruby bm_string.rb
                 user     system      total        real
 dup         0.370000   0.020000   0.390000 (  0.389034)
 [0..-1]     0.100000   0.020000   0.120000 (  0.116802)
 [0..-2]     0.100000   0.020000   0.120000 (  0.120162)


 ** After

 $ macruby bm_string.rb
                 user     system      total        real
 dup         0.020000   0.010000   0.030000 (  0.015249)
 [0..-1]     0.010000   0.000000   0.010000 (  0.005772)
 [0..-2]     0.110000   0.030000   0.140000 (  0.136033)
 }}}

 However, When I run RubySpec, displays error message about GC X(

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/1157#comment:2>
MacRuby <http://macruby.org/>