Issue #7984 has been updated by jcole1989 (James Coleman).


I have the latest command line tools and Xcode 4.6 installed. The gcc error is known, see: https://bugs.ruby-lang.org/issues/7956 -- the solution was that rvm switched to Clang as the default CC for now.

But all of that still leaves the issue of why the Clang build of 2.0.0 runs so much more slowly than the Clang build of 1.9.3.
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Bug #7984: Severe speed issues in 2.0.0 compiled with Clang
https://bugs.ruby-lang.org/issues/7984#change-37192

Author: jcole1989 (James Coleman)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: 


I've been comparing Ruby 2.0.0 with 1.9.3-head, both compiled with the same basic set of CFLAGs with Clang on Mac OS 10.8 (Mountain Lion). A decent sized rails app was showing performance degradations, so I looked into the most basic of (micro)benchmarks. Running the following:

t = Benchmark.measure do
  50000000.times { Object.new }
end

Gives me the following output:

1.9.3-head: 11.240000 0.000000 11.240000 ( 11.247285)
2.0.0p0: 23.610000 0.010000 23.620000 ( 23.629643)

Ruby 2.0.0 takes over twice as long as 1.9.3. In contrast, running the same test under rubies compiled with GCC on linux (unfortunately I can't do a direct test on OSX because 2.0.0 currently won't compile under the current apple gcc 4.2) Ruby 2.0.0 shows a 15-20% speed improvement over 1.9.3.

So it seems there's a severe speed regression interaction with the ruby 2.0.0 code and Clang.


-- 
http://bugs.ruby-lang.org/