Re: Re: Believably slow..

Not that it matters much ...

use Benchmark 'cmpthese';

#16777216

cmpthese(
9000,
#-3,
{
    'c-style' => sub {
            for my $num (0 .. 1000) {}
            return();
     },
    'rangefor' => sub {
            for( my $num = 0; $num < 1000; $num++) {}
            return();
     },
});

__END__

Benchmark: running c-style, rangefor, each for at least 3 CPU seconds.
+..
   c-style:  4 wallclock secs ( 3.20 usr +  0.00 sys =  3.20 CPU) @ 64
+94.54/s (n=20802)
  rangefor:  3 wallclock secs ( 3.27 usr +  0.00 sys =  3.27 CPU) @ 37
+93.02/s (n=12388)
           Rate rangefor  c-style
rangefor 3793/s       --     -42%
c-style  6495/s      71%       --

Benchmark: timing 9000 iterations of c-style, rangefor...
   c-style:  1 wallclock secs ( 1.44 usr +  0.00 sys =  1.44 CPU) @ 62
+58.69/s (n=9000)
  rangefor:  3 wallclock secs ( 2.39 usr +  0.00 sys =  2.39 CPU) @ 37
+65.69/s (n=9000)
           Rate rangefor  c-style
rangefor 3766/s       --     -40%
c-style  6259/s      66%       --
[download]

update: lol

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Comment on Re: Re: Believably slow.. Download Code

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Re: Re: Re: Believably slow..
by demerphq (Chancellor) on Jun 22, 2003 at 15:35 UTC

This benchmark would be far better if you had named the subroutines correctly. :-) Youll notice that you have the names for the two subs reversed.

Also, I personally wouldn't do a benchmark with an empty block. Put something in it just in case Perl gets smart enough to optimize both of those subroutines down to sub{} and then maybe even just tosses any calls to them becuase they dont really do anything....

use Benchmark 'cmpthese';

#16777216

my @num=0..1000;
my ($x,$y,$z);


my $subhash={
    'rangefor' => sub {
            for my $num (0 .. 1000) { $x++ }
            return();
     },
     'c-style' => sub {
            for( my $num = 0; $num < 1000; $num++) { $y++ }
            return();
     },
     'foreach' => sub {
            foreach my $num (@num) { $z++ }
            return();
     },
};

cmpthese(-3,$subhash) for 1..3;

__END__
Benchmark: running c-style, foreach, rangefor, each for at least 3 CPU
+ secs...
   c-style:  3 wall secs ( 3.25 usr + 0 sys =  3.25 CPU) @3039.64/s (n
+=9891)
   foreach:  3 wall secs ( 3.30 usr + 0 sys =  3.30 CPU) @3930.39/s (n
+=12986)
  rangefor:  3 wall secs ( 3.22 usr + 0 sys =  3.22 CPU) @4133.68/s (n
+=13327)
           Rate  c-style  foreach rangefor
c-style  3040/s       --     -23%     -26%
foreach  3930/s      29%       --      -5%
rangefor 4134/s      36%       5%       --
Benchmark: running c-style, foreach, rangefor, each for at least 3 CPU
+ secs...
   c-style:  3 wall secs ( 3.16 usr + 0 sys =  3.16 CPU) @3046.59/s (n
+=9612)
   foreach:  3 wall secs ( 3.20 usr + 0 sys =  3.20 CPU) @3921.37/s (n
+=12568)
  rangefor:  4 wall secs ( 3.18 usr + 0 sys =  3.18 CPU) @4080.31/s (n
+=12955)
           Rate  c-style  foreach rangefor
c-style  3047/s       --     -22%     -25%
foreach  3921/s      29%       --      -4%
rangefor 4080/s      34%       4%       --
Benchmark: running c-style, foreach, rangefor, each for at least 3 CPU
+ secs...
   c-style:  3 wall secs ( 3.14 usr + 0 sys =  3.14 CPU) @3037.84/s (n
+=9554)
   foreach:  3 wall secs ( 3.30 usr + 0 sys =  3.30 CPU) @3941.12/s (n
+=12986)
  rangefor:  3 wall secs ( 3.10 usr + 0 sys =  3.10 CPU) @4079.25/s (n
+=12662)
           Rate  c-style  foreach rangefor
c-style  3038/s       --     -23%     -26%
foreach  3941/s      30%       --      -3%
rangefor 4079/s      34%       4%       --
[download]

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