in reply to Optimize debugging subs

Your more elegant equivalent achives the same leval of optimization, print $_[0] if ENABLE_DEBUG; evaluates to false.

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Re^2: Optimize debugging subs
by danb (Friar) on Apr 05, 2006 at 04:20 UTC
    This benchmark indicates that you are wrong. 
    sub ENABLE_DEBUG () { 0 }
sub debug_inelegant { print $_[0]; }
sub debug_elegant { print $_[0] if ENABLE_DEBUG; }

use Benchmark qw(:all) ;

cmpthese( 30000000, 
    { 
        'inelegant' => "debug_inelegant 'test' if ENABLE_DEBUG;",
        'elegant'   => "debug_elegant 'test';"
    },
);

    [download]
    Output: 
                    Rate   elegant inelegant
elegant    3337041/s        --      -95%
inelegant 62500000/s     1773%        --

    [download]

    --Dan

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[d/l]
[select]
      According to your benchmark, elegant takes 0.0000003 seconds (0.3 microseconds) to execute. What's the problem?
[reply]
[d/l]

        Good point; what about this?

        Lots debug() calls inside a long-running loop, inside many very frequently called subs, running in a virtual server program (with access to only 10% of the CPU), running on a commodity server (Pentium-III 1.3 Ghz), being accessed by many simultaneous clients.

        That's a lot different than the Benchmark I just ran on a Athlon64 X2 2.4ghz.

        Besides, what about the enjoyment of knowing that there is *no* debugging code in your program?

        --Dan

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