From: Luis Lavena <luislavena@...>
Date: 2012-02-13T09:29:23+09:00
Subject: [ruby-core:42513] [ruby-trunk - Bug #3924] Performance bug (in require?)


Issue #3924 has been updated by Luis Lavena.


satoshi shiba wrote:
> 
> May I ask current status of this problem?
> "rb_file_expand_path()" is still a bottleneck of "rb_require_safe()".
> So, I'm interested in this problem.
> 
> If memory leak is a problem, how about collecting strings at the time of mark phase.
> I made a patch which is based on Shyouhei's patch to resolve memory leak.
> A patch( https://gist.github.com/1805919 ) collects cached strings at the time of mark phase.

Please see Feature #5767, proposed usage of cached expanded paths:

https://bugs.ruby-lang.org/issues/5767

----------------------------------------
Bug #3924: Performance bug (in require?)
https://bugs.ruby-lang.org/issues/3924

Author: Carsten Bormann
Status: Assigned
Priority: Normal
Assignee: Yuki Sonoda
Category: core
Target version: 2.0.0
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



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