From: Dave Thomas <Dave@...>
Date: 2002-06-20T15:01:53+09:00
Subject: Re: Why is I/O slow?

Clifford Heath <cjh_nospam@managesoft.com> writes:

> Ok, folk, time to try again. It's nothing to do with SHA-1.
> I deleted the SHA-1 update from the code so it's the same
> as "cat file >/dev/null", and it takes *ages*:
> 
> $ time cat /tmp/ten_megabytes >/dev/null
> real    0m0.040s
> user    0m0.000s
> sys     0m0.040s
> $  time ruby cat.rb /tmp/ten_megabytes
> real    0m1.262s
> user    0m1.230s
> sys     0m0.030s
> $ time ruby sha1.rb /tmp/ten_megabytes
> 8c206a1a87599f532ce68675536f0b1546900d7a        /tmp/ten_megabytes
> real    0m1.693s
> user    0m1.600s
> sys     0m0.090s
> $ time perl cat.pl < /tmp/ten_megabytes >/dev/null
> real    0m0.044s
> user    0m0.010s
> sys     0m0.030s
> 
> I gotta say folk, this is going to make it *very* hard to convince others
> here to use ruby, and that's a shame... *30* times slower than Perl?!!
> Code available on request.

   dave[/tmp 0:58:39] cat >cat.rb
   print $stdin.read

   dave[/tmp 0:59:42] time cat <12meg >/dev/null 
   cat < 12meg > /dev/null  0.00s user 0.05s system 102% cpu 0.049 total

   dave[/tmp 0:59:52] time ruby cat.rb <12meg >/dev/null 
   ruby cat.rb < 12meg > /dev/null  1.78s user 0.14s system 100% cpu 1.917 total


Slower than 'cat', but still a lot less that 86s.



Dave