I was trying to save memory by not having to load Config.pm. But because of your remark, I decided to do a Benchmark: 
Benchmark: timing 1000 iterations of open, use...
 open: 38 wallclock secs ( 2.62 usr  0.00 sys + 16.14 cusr 12.96 csys = 31.72 CPU) @ 381.68/s (n=1000)
  use: 14 wallclock secs (13.15 usr +  0.00 sys = 13.15 CPU) @ 76.05/s (n=1000)

This surprised me a lot!. The fork() approach with open() seems to be 5 times as fast as loading Config.pm!

Alas, I think I stumbled upon a bug / feature / problem of Benchmark: apparently, only "usr" CPU is taken into account when calculating the number of runs/second, and the "usr" CPU is of course a lot less than with fork/open than it is with use.

Still, the fork/open approach only takes 2.5 times as much CPU as loading Config.pm. I wonder if that is a testament of the efficiency of fork(), or the slowness of Config.pm. ;-)

The code: 

use Benchmark;

timethese( 1000, {
 open => sub {
     open my $handle, $^X.' -V:ccflags |';
     my $ccflags = <$handle>;
     delete $INC{'Config.pm'};
 },
 use => sub {
     require Config; Config->import;
     my $ccflags = $Config{ccflags};
     delete $INC{'Config.pm'};
 },
} );

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Liz

In reply to Re: &bull;Re: Check whether your hash keys have random order by liz
in thread Check whether your hash keys have random order by liz

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