note
blakem
Interesting.... and its nearly as fast as inlining it in C.
<code>
#!/usr/bin/perl -w
use strict;
use Benchmark 'cmpthese';
my $str = "some string here";
die unless (pop_chord($str) . inlined($str) . _substr($str) .
_unpack($str) . _match($str)
eq substr($str,0,1)x5);
cmpthese( 500000, {
'pop_chord' => sub { pop_chord($str) },
'inlined' => sub { inlined($str) },
'_substr' => sub { _substr($str) },
'_unpack' => sub { _unpack($str) },
'_match' => sub { _match($str) },
}
);
sub pop_chord {
chr ord pop
}
sub _substr {
substr pop,0,1
}
sub _unpack {
unpack"a",pop
}
sub _match {
(pop=~/(.)/s)[0]
}
use Inline C => <<'END_OF_C_CODE';
char inlined(char* str) {
return str[0];
}
END_OF_C_CODE
__END__
Benchmark: timing 500000 iterations of _match, _substr, _unpack, inlined, pop_chord...
_match: 3 wallclock secs ( 3.98 usr + 0.00 sys = 3.98 CPU) @ 125628.14/s (n=500000)
_substr: 2 wallclock secs ( 1.45 usr + 0.00 sys = 1.45 CPU) @ 344827.59/s (n=500000)
_unpack: 4 wallclock secs ( 2.68 usr + 0.00 sys = 2.68 CPU) @ 186567.16/s (n=500000)
inlined: 1 wallclock secs ( 0.58 usr + 0.00 sys = 0.58 CPU) @ 862068.97/s (n=500000)
pop_chord: 1 wallclock secs ( 1.30 usr + 0.00 sys = 1.30 CPU) @ 384615.38/s (n=500000)
Rate _match _unpack _substr pop_chord inlined
_match 125628/s -- -33% -64% -67% -85%
_unpack 186567/s 49% -- -46% -51% -78%
_substr 344828/s 174% 85% -- -10% -60%
pop_chord 384615/s 206% 106% 12% -- -55%
inlined 862069/s 586% 362% 150% 124% --
</code>
<P>
-Blake
235952
235952