Hi, I'm just curious about these variations in performance between creating subs at run-time vs compile-time. Does anyone have some insight into what's going on behind the scenes?

#!/usr/bin/perl
use Benchmark;

BEGIN { *begin = sub {} }

INIT { *init = sub {} }

sub declared {}

*runtime = sub {};

timethese(50000, {
    begin      => sub { begin    for (1 .. 1000) },
    init       => sub { init     for (1 .. 1000) },
    declared   => sub { declared for (1 .. 1000) },
    runtime    => sub { runtime  for (1 .. 1000) }
});

[download]

Results:

Benchmark: timing 50000 iterations of begin, declared, init, runtime...
     begin:  9 wallclock secs ( 9.31 usr +  0.01 sys =  9.32 CPU) @ 5364.81/s (n=50000)
  declared: 10 wallclock secs ( 9.54 usr +  0.01 sys =  9.55 CPU) @ 5235.60/s (n=50000)
      init:  2 wallclock secs ( 2.11 usr +  0.00 sys =  2.11 CPU) @ 23696.68/s (n=50000)
   runtime:  2 wallclock secs ( 2.08 usr +  0.00 sys =  2.08 CPU) @ 24038.46/s (n=50000)
I am running Perl v5.10.0 on Ubuntu 9.04 (Jaunty) x86_64 2.6.28-17-generic. Let me know if you need more info. Thanks!

In reply to Subs created at run-time are faster than those created at compile-time by neodon

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.