From: Paul Brannan <redmine@...>
Date: 2008-10-08T00:08:12+09:00
Subject: [ruby-core:19171] [Feature #619] improved performance of BASIC_OP_UNREDEFINED_P

Feature #619: improved performance of BASIC_OP_UNREDEFINED_P
http://redmine.ruby-lang.org/issues/show/619

Author: Paul Brannan
Status: Open, Priority: Normal
Category: core

ruby_vm_redefined_flag uses bit arithmetic to manage which flags have been redefined.  Performance can be improved by using a separate word for each redefined operation.  In 100 runs user time was improved 1.4% at the 95th percentile:

require 'benchmark'

Percentile     Before    After
50             7.60      7.52
90             7.73      7.63
95             7.76      7.65
98             7.92      7.69
99             8.06      7.73

Performance numbers at the 98th percentile and above likely includes outliers.

Test was run on a dual Xeon 3.06GHz.

Test script:

N = 10_000_000

Benchmark.bm { |x|
  x.report do
    for i in 1..N do
      1+1
    end
  end
}


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