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!

Having a -debug option doesn't mean you need to do anything at execution time. You can check options in a BEGIN block and set a constant that controls whether debug statements will be optimized away or not:

$ 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";
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Without the -debug option, the print and if are optimized away to be just an empty statement:

$ 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
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With -debug, the if is optimized away leaving just the debug call:

$ 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
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