[MacRuby] #1048: Performance of Hash with an Array as a key

MacRuby ruby-noreply at macosforge.org
Thu Dec 16 20:03:24 PST 2010


#1048: Performance of Hash with an Array as a key
----------------------------------+-----------------------------------------
 Reporter:  yasuimao@…            |       Owner:  lsansonetti@…        
     Type:  defect                |      Status:  new                  
 Priority:  blocker               |   Milestone:  MacRuby 1.0          
Component:  MacRuby               |    Keywords:                       
----------------------------------+-----------------------------------------
Changes (by lsansonetti@…):

  * milestone:  => MacRuby 1.0


Comment:

 After looking at this example, I notice 2 problems:

  * First, because Array#hash in MacRuby returns the same hash code for
 same-sized arrays, in this very specific case, it means the hash lookup
 will always hit the same slot range, then perform comparison operations on
 the various keys to find the right slot. This problem is already reported
 in #791 and I moved its milestone to 1.0.

  * Second, doing comparison operations on array keys is poorly optimized,
 resulting in many calls to the dispatcher and other costly operations.

 Moving this bug to 1.0.

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/1048#comment:1>
MacRuby <http://macruby.org/>



More information about the macruby-tickets mailing list