Vanity, Vanity, all is Vanity

• What went wrong here?

• The actual code was something like this:

        my @filenames = glob("/tmp/*");

        timethese(10**7, {
                'CODE A' => '@sorted = sort { -M $b <=> -M $a } @filenames;',
                ...
        );

• When you give strings to Benchmark, it executes them with eval

• It does the eval internally, inside of Benchmark.pm

• This is outside the scope of my @filenames

• The benchmark is using @Benchmark::filenames, which is empty

• You can indeed sort an empty list in 3.7 microseconds

• But the results were entirely meaningless

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Copyright © 2003 M. J. Dominus