Actually, if you agree that the following code would be valid for a benchmark, then you might be surprised.
Code:
#!/usr/bin/perl -w
use strict;
use Benchmark qw(:all);
timethese(
1_000_000,
{ 'unpack' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my ( $name1, $name3, $name2 ) = unpack( q{a10 a14 X16 a3),
+ $str );
},
'map_browseruk' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my @fields = (
[ name1 => { start => 0, len => 10 } ],
[ name2 => { start => 8, len => 3 } ],
[ name3 => { start => 11, len => 14 } ],
);
my ( $name1, $name2, $name3 ) = map { substr $str, $_->[1]
+{start}, $_->[1]{len} } @fields;
},
'unpack_setup' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my ( $name1, $name3, $name2 );
},
'map_browseruk_setup' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my @fields = (
[ name1 => { start => 0, len => 10 } ],
[ name2 => { start => 8, len => 3 } ],
[ name3 => { start => 11, len => 14 } ],
);
my ( $name1, $name2, $name3 );
},
'map_jwkrahn' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my @fields = (
[ name1 => { start => 0, len => 10 } ],
[ name2 => { start => 8, len => 3 } ],
[ name3 => { start => 11, len => 14 } ],
);
my $format = join q[ ],
map sprintf( q[x%d a%d X%d], @{ $_-[1] }{qw[start len]
+}, $_->[1]{start} + $_->[1]{len} ), @fields;
my ( $name1, $name2, $name3 ) = unpack( $format, $str );
},
'map_jwkrahn_setup' => sub {
my $str = q{0123456789abcdefghijklmnopqrstuvwxyz};
my @fields = (
[ name1 => { start => 0, len => 10 } ],
[ name2 => { start => 8, len => 3 } ],
[ name3 => { start => 11, len => 14 } ],
);
my $format = join q[ ],
map sprintf( q[x%d a%d X%d], @{ $_-[1] }{qw[start len]
+}, $_->[1]{start} + $_->[1]{len} ), @fields;
my ( $name1, $name2, $name3 );
},
}
);
Results (1_000_000 iterations):
Benchmark: timing 1000000 iterations of map_browseruk,
map_browseruk_setup, map_jwkrahn, map_jwkrahn_setup, unpack,
unpack_setup...
map_browseruk: 16 wallclock secs (14.77 usr + 0.04 sys = 14.81 CPU)
@ 67521.94/s (n=1000000)
map_browseruk_setup: 9 wallclock secs ( 9.27 usr + 0.03 sys = 9.30
CPU) @ 107526.88/s (n=1000000)
map_jwkrahn: 29 wallclock secs (23.17 usr + 0.04 sys = 23.21 CPU) @
43084.88/s (n=1000000)
map_jwkrahn_setup: 23 wallclock secs (20.23 usr + 0.03 sys = 20.26
CPU) @ 49358.34/s (n=1000000)
unpack: 4 wallclock secs ( 2.43 usr + 0.00 sys = 2.43 CPU) @
411522.63/s n=1000000)
unpack_setup: 1 wallclock secs ( 0.44 usr + 0.00 sys = 0.44 CPU)
@ 2272727.27/s (n=1000000)
I must say I was surprised. I included the times for "setup"-that is, everything but the operation itself, on the idea that perhaps the setup might have taken longer for the one method than another. Thoughts....?
Update (26-Sept-2006): Updated formatting of results.
Update (26-Sept-2006): Fixed typo. (Thanks to BrowserUk for pointing it out.)
Update (26-Sept-2006): Fixed 2nd typo. (Thanks to chargrill for pointing it out.) | [reply]
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If you hardcode the template to unpack, of course it will be quicker--but when the input data changes, the template won't without programmer intervention--which kinda negates the value of the benchmark.
Actually, your entire benchmark is pretty suspect and you are comparing a bunch of entirely different things:
- A hardcoded unpack.
- Two different implementations of the original challenge: parsing the data according to the contents of the input structure.
- Three other bit of random code that do nothing in particlar to do with the problem--your "setup" stuff.
So, no. I wouldn't agree that this is a valid benchmark :) Sorry.
Also, please use cmpthese for benchmarking, the output from timethese is all but unintelligable.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
| [reply]
[d/l] |
map sprintf( q[x%d a%d X%d], Q{ $_-[1] }{qw[start len]
+}, $_->[1]
.............................................^
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
| [reply]
[d/l]
[select] |