From: "Jarosław Skrzypek" Date: 2011-06-20T18:01:52+09:00 Subject: [ruby-core:37239] [Ruby 1.9 - Bug #3924] Performance bug (in require?) Issue #3924 has been updated by Jaros��aw Skrzypek. You might be also interested in my very short patch: https://gist.github.com/1035322 Basically it reorders conditions to start with fastest ones and execute slower ones only if needed. Here is also some description: http://www.lunarlogicpolska.com/blog/2011/06/14/tracing-processes-for-fun-and-profit.html ---------------------------------------- Bug #3924: Performance bug (in require?) http://redmine.ruby-lang.org/issues/3924 Author: Carsten Bormann Status: Assigned Priority: Normal Assignee: Yuki Sonoda Category: core Target version: 1.9.3 ruby -v: - =begin Running irb < /dev/null in 1.9.2 causes 3016 calls to lstat64. For instance, there is a sequence of 28 repetitions each of lstat calls to all 6 non-empty path prefixes of /opt/local/lib/ruby1.9/1.9.1/irb.rb -- a total of 170 lstats apparently just to load this file; another set of lstats then occurs later for another 18 (times 6) times. Clearly, something is running amok in the calling sequence rb_require_safe -> realpath_rec -> lstat. Another example: Running a simple test with the baretest gem causes 17008 calls to lstat. According to perftools.rb, 80 % of the 1.2 seconds of CPU is used in Kernel#gem_original_require (and another 12 in GC, some of which may be caused by this). =end -- http://redmine.ruby-lang.org