Issue #5562 has been updated by Hiroshi Shirosaki.

File win_io_for_r33656.patch added

Thank you for your help.

Previous patch have a bug of IO.copy_stream. So, many errors have occurred in rubygems and http tests.
I assume "This program cannot be run in DOS mode." is related to above issue. I had same error.
Does Ruby install process use IO.copy_stream?

I was able to fix that bugs. make test-all failures and errors have reduced, although this still have some failures and errors.
Now I can run ruby on rails with patched ruby.
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Feature #5562: Improvement of Windows IO performance
http://redmine.ruby-lang.org/issues/5562

Author: Hiroshi Shirosaki
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


=begin
I suggest a patch to improve Windows IO performance.

Ruby's text mode IO is much slower than binary mode.
On Windows text mode is default, so Windows IO is slow.
I assume that's mainly because of CRLF linefeed code conversion.

My idea to improve IO performance is as below.
- Change default linefeed conversion from Universal newline to CRLF newline on Windows
- Use binary mode process with OS's text mode if only CRLF conversion is needed
- Use Ruby's text mode with universal newline conversion if encoding conversion is needed

Although that causes io.c code to be more complicated, IO with CRLF conversion performance seems to be improved much.
I confirmed "make test-all TEST=ruby" have been passed. There was 3 errors, but ruby without this patch had same errors.
I think this patch doesn't affect other OS.

Line endings of "p" or "puts" writing is LF on trunk, but CRLF on 1.8.7 or 1.9.2.
This patch reverts to CRLF.


Here is #1332 benchmark test and results.

time = [Time.new]
c = ''
'aaaa'.upto('zzzz') {|e| c << e}
4.times { c << c }
time << Time.new
File.open('out.file','w') { |f| f.write(c) }
time << Time.new
c = File.open('out.file','r') { |f| f.read }
time << Time.new
0.upto(time.size - 2) {|i| p "#{i} #{time[i+1]-time[i]}" }


- Result

ruby 1.8.7 (2011-06-30 patchlevel 352) [i386-mingw32]
"0 0.78125"
"1 0.6875"
"2 0.5625"

ruby 2.0.0dev (2011-11-03) [i386-mingw32]
"0 0.59375"
"1 1.09375"
"2 1.296875"

ruby 2.0.0dev (2011-11-03 trunk 33615) [i386-mingw32] with this patch
"0 0.625"
"1 0.65625"
"2 0.34375"
=end



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