I am always qualifying the calls with an "if" to avoid the cost of a call/return pair. Is there anything else I can do to eliminate more of the performance overhead? A better method? BTW, I want the debug calls to be an execution time option. The program has a usage with a "-debug" option. Thanks!

$ cat deb.pl
#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

my $FOO_DEBUG_MODE;
BEGIN { GetOptions("debug", \$FOO_DEBUG_MODE) }
use constant FOO_DEBUG_MODE => $FOO_DEBUG_MODE;

print "debug statment\n" if FOO_DEBUG_MODE;
print "done!\n";
[download]

$ perl -MO=Deparse deb.pl
use Getopt::Long;
BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
use strict 'refs';
my $FOO_DEBUG_MODE;
sub BEGIN {
    GetOptions 'debug', \$FOO_DEBUG_MODE;
}
use constant ('FOO_DEBUG_MODE', $FOO_DEBUG_MODE);
'???';
print "done!\n";
deb.pl syntax OK
[download]

$ perl -MO=Deparse deb.pl -debug
use Getopt::Long;
BEGIN {${^WARNING_BITS} = "UUUUUUUUUUUU"}
use strict 'refs';
my $FOO_DEBUG_MODE;
sub BEGIN {
    GetOptions 'debug', \$FOO_DEBUG_MODE;
}
use constant ('FOO_DEBUG_MODE', $FOO_DEBUG_MODE);
print "debug statment\n";
print "done!\n";
deb.pl syntax OK
[download]

Thank you! This is exactly what I was looking for!

Have you profiled or benchmarked your code to see if those "if" statements are really causing any performance issues? Usually you'll find those bottlenecks elsewhere, such as in file I/O or database calls.

Here's an article on Log4Perl you might find useful: Retire your debugger....

Thanks for the pointer. I will look into using that within my debug function.

Have you measured the overhead the debugging calls add? In other words, are you sure that moving the if into foo_debug will make a noticeable difference?

I have not measured. Yet, I have tons of these debug calls with many inside critical hefty loops so I assume that every fraction of a second will help.

Don't assume. Measure.