Any ideas why 'Errno' contants can be inlined but 'Socket' and 'Fcntl' constants can't? 
use Benchmark qw( cmpthese );

use Errno           qw( EAGAIN          );
use Fcntl           qw( O_NONBLOCK      );
use Socket;           # AF_INET

BEGIN {
    our @const = qw( EAGAIN O_NONBLOCK AF_INET );
    for my $const (@const) {
        eval "sub _$const () { ".&$const.' }';
        die $@ if $@;
    }
}

our ($CONST_VALUE, $import, $inline, $scalar);
for my $const (@const) {
    print "\n>>> Testing: $const\n";
    $CONST_VALUE = &$const;
    cmpthese(5000000, {
        import      => '$import =  '.$const.';',
        inline      => '$inline = _'.$const.';',
        scalar      => '$scalar = $CONST_VALUE;',
    });
    printf "Result: %d %d %d\n", $import, $inline, $scalar;
}
__END__
>>> Testing: EAGAIN
            Rate import scalar inline
import 4716981/s     --    -5%   -19%
scalar 4950495/s     5%     --   -15%
inline 5813953/s    23%    17%     --
Result: 11 11 11

>>> Testing: O_NONBLOCK
            Rate import scalar inline
import  904159/s     --   -84%   -84%
scalar 5494505/s   508%     --    -5%
inline 5813953/s   543%     6%     --
Result: 2048 2048 2048

>>> Testing: AF_INET
            Rate import inline scalar
import  927644/s     --   -84%   -84%
inline 5747126/s   520%     --    -1%
scalar 5813953/s   527%     1%     --
Result: 2 2 2

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In reply to Slow constants by powerman

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