Rate substr_it unpack_it
substr_it 2341/s        --      -47%
unpack_it 4384/s       87%        --
Results tally

##</code><code>##

#! perl -slw
use strict;
use vars qw[$line @s @s2 @u1 @u2];
use Benchmark qw[cmpthese];

$line = (join'','a' .. 'y') x 40;

sub substr_it{
	my @bits;
	push @bits, substr $_[0], 413,  30;
	push @bits, substr $_[0], 373,  30;
	push @bits, substr $_[0], 343,  30;
	push @bits, substr $_[0], 245,  15;
	push @bits, substr $_[0], 679,  30;
	push @bits, substr $_[0],  10,  10;
	push @bits, substr $_[0], 900, 100;
	push @bits, substr $_[0], 500,   2;
	push @bits, substr $_[0], 313,  30;
	push @bits, substr $_[0], 844,  44;
	push @bits, substr $_[0], 111,   1;
	push @bits, substr $_[0], 100, 100;
	push @bits, substr $_[0], 454,  30;
	push @bits, substr $_[0], 240,   3;
	push @bits, substr $_[0], 236,   4;

	@bits;
}


sub unpack_it{
	my $fmt = '@413A30 @373A30 @343A30 @245A15 @679A30 @10A10 @900A100'
		    . '@500A2 @313A30 @844A44 @111A1 @100A100 @454A30 @240A3 @236A4';

	unpack( $fmt, $_[0]);
}

cmpthese( -3, {
	substr_it	=> '@s  = substr_it  $line;',
	unpack_it	=> '@u1 = unpack_it  $line;',
});

print 'Results tally';

__END__
C:\test>226666
Benchmark:
running
 substr_it, unpack_it
, each for at least 3 CPU seconds
...

 substr_it:  4 wallclock secs ( 3.01 usr +  0.00 sys =  3.01 CPU) @ 2340.74/s (n=7055)

 unpack_it:  3 wallclock secs ( 3.11 usr +  0.00 sys =  3.11 CPU) @ 4383.55/s (n=13646)

            Rate substr_it unpack_it
substr_it 2341/s        --      -47%
unpack_it 4384/s       87%        --
Results tally

C:\test>

##</code><code>##

sub substr_it{
	( substr( $_[0], 413,  30),
	, substr( $_[0], 373,  30),
	, substr( $_[0], 343,  30),
	, substr( $_[0], 245,  15),
	, substr( $_[0], 679,  30),
	, substr( $_[0],  10,  10),
	, substr( $_[0], 900, 100),
	, substr( $_[0], 500,   2),
	, substr( $_[0], 313,  30),
	, substr( $_[0], 844,  44),
	, substr( $_[0], 111,   1),
	, substr( $_[0], 100, 100),
	, substr( $_[0], 454,  30),
	, substr( $_[0], 240,   3),
	, substr( $_[0], 236,   4),
	);
}

##</code><code>##


            Rate substr_it unpack_it
substr_it 3836/s        --      -14%
unpack_it 4460/s       16%        --
Results tally

##</code><code>##

use constant FORMAT =>
'@413A30 @373A30 @343A30 @245A15 @679A30 @10A10 @900A100 @500A2 
. @313A30 @844A44 @111A1 @100A100 @454A30 @240A3 @236A4';

sub unpack_it{
	unpack( FORMAT, $_[0]);
}
# gives
            Rate substr_it unpack_it
substr_it 3821/s        --      -16%
unpack_it 4575/s       20%        --
Results tally