use Benchmark;
use CGI qw/:cgi /;
use CGI::Simple;
$ENV{'QUERY_STRING'} = 'foo=bar&baz=boo';
$q = new CGI;
$s = new CGI::Simple;
timethese(250000, {'CGI' =>'$q->param("baz")', 'Simple' => '$s->param(
+"baz")'});
[download]

And even then, with this test, while it's fair in how fast it accesses, the real concern would be the speed in breaking down the query string. I propose a better test would be :

use Benchmark;
use CGI qw/:cgi /;
use CGI::Simple;
$ENV{'QUERY_STRING'} = 'foo=bar&baz=boo';
timethese(250000, {'CGI' =>
                      '$q = new CGI; $q->param("baz")', 
                   'Simple' => 
                      '$s = new CGI::Simple; $s->param(
+"baz")'});
[download]

-----------------------------------------------------
Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
"I can see my house from here!"
It's not what you know, but knowing how to find it if you don't know that's important

The qw/:cgi/ part is wrong as noted above but as you note there are a number of factors to CGI speed. Have a look at CGI::Simple vs CGI.pm - Is twice as fast good enough? for a much more thorough analysis.

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

Actually you completely fail to understand how CGI.pm works. When you use CGI; you import 0 methods. The methods are available via the OO interface and compiled on demand. When you use CGI qw/:cgi/; you import and compile the basic cgi methods (which you would otherwise not do with a straight use CGI;). As we are making OO calls this is a complete waste of time. Running your example you can see that the time remains essentially the same as expected (loading the extra methods once (with the use CGI qw/:cgi/;) adds about a second to the load time but this is a once off price and we are then looping.

use Benchmark;
use CGI qw/:cgi /;
use CGI::Simple;
$ENV{'QUERY_STRING'} = 'foo=bar&baz=boo';
$q = new CGI;
$s = new CGI::Simple;
timethese(250000, {'CGI' =>'$q->param("baz")', 'Simple' => '$s->param(
+"baz")'});

__DATA__
Benchmark: timing 250000 iterations of CGI, Simple...
       CGI: 29 wallclock secs (27.53 usr +  0.00 sys = 27.53 CPU) @ 90
+81.00/s (n=250000)
       Simple: 10 wallclock secs ( 9.99 usr +  0.00 sys =  9.99 CPU) @
+ 25025.03/s (n=250000)
[download]

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print