From: Ilya Vazhev <vil@...>
Date: 2003-01-26T22:20:24+09:00
Subject: Windows ports: performance of cygwin vs mswin32 ruby

Hi,

I found that recently released ruby 1.6.8 from the
distribution from The Pragmatic Programmers (not to blame them)
is _MUCH_ slower in my IO-processing scripts than their previous
ruby 1.6.5. I figured out that 1.6.5 was based on cygwin
while 1.6.8 is "native" mswin32.

Here is the simple test and results: 

$ cat io_test.rb 
f=open(ARGV[0],"r")
f.binmode
slice=1024*1024
while true
        s=f.read(slice)
        if s==nil
                break
        end
end
puts f.tell
f.close

$ ruby -v
ruby 1.6.5 (2001-09-19) [i386-cygwin]

$ time ruby io_test.rb mpich.tar.gz
12313304

real    0m0.441s
user    0m0.020s
sys     0m0.000s

$ /cygdrive/d/Programs/ruby/bin/ruby -v
ruby 1.6.8 (2002-12-24) [i586-mswin32]

$ time /cygdrive/d/Programs/ruby/bin/ruby io_test.rb mpich.tar.gz
12313304

real    0m34.129s
user    0m0.010s
sys     0m0.010s

So "proccessing" of file ~12Mb takes 0.5 and 30 seconds!

What could be a reason of such a slowness of mswin32-ruby?