You lost me there, when might it be less efficient to "specify a multiple step path" ?

I don't really use File::Find much, so I super searched for some example code to try benchmarking, and from what i can tell, all other factors being equal/irrelevant, no_chdir seems to be faster.

Here's an example from one of your snippets... 

#!/usr/local/bin/perl

use Benchmark qw(cmpthese);
use File::Find;

my %results;

my $wanted = sub {
  if (-l) { # it's a symlink
    my ($dev, $ino) = lstat _; # reuse info from -l
    push @{$results{"$dev $ino"}}, $File::Find::name;
    if (-e) { # that points somewhere else
      my ($dev, $ino) = stat _; # reuse info from -e
      push @{$results{"$dev $ino"}}, "symlink:$File::Find::name";
    }
  } else {
    my ($dev, $ino) = stat;
    push @{$results{"$dev $ino"}}, $File::Find::name;
  }
};

my @dirs = qw(/bin /usr/bin /usr/sbin); # change this to "/" to do the


cmpthese(1000, {
    chdir => sub {
    %results=();
    find { wanted=>$wanted }, @dirs;
    }, 
    no_chdir => sub {
    %results=();
    find { wanted=>$wanted, no_chdir=>1}, @dirs;
    }
});

__END__

laptop:~> monk.pl
Benchmark: timing 1000 iterations of chdir, no_chdir...
     chdir: 79 wallclock secs (61.68 usr 13.90 sys +  1.23 cusr  1.03 
+csys = 77.84 CPU) @ 13.23/s (n=1000)
  no_chdir: 82 wallclock secs (61.94 usr 17.99 sys +  1.07 cusr  1.09 
+csys = 82.09 CPU) @ 12.51/s (n=1000)
           Rate no_chdir    chdir
no_chdir 12.5/s       --      -5%
chdir    13.2/s       6%       --

[download]

In reply to Re^2: Why does File::Find chdir? by hossman
in thread Why does File::Find chdir? by jplindstrom

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