Hi,
at some other forum we had the discussion which is the fastest way to read all files of a directory
at some other forum we had the discussion which is the fastest way to read all files of a directory
- opendir $DIR, $folder; while(my $file = readdir $DIR) ...
- foreach my $file (glob "$folder/*") ...
- opendir $DIR, $folder; my @files = grep { ... } readdir $DIR; foreach my $file (@files) ...
the result does not make sence to me, but maybe you can tell me why#!/usr/bin/perl use strict; use warnings; use Benchmark qw(:all); my %folders = ( Temp1 => 10, Temp2 => 100, Temp3 => 1000, Temp4 => 5000, Temp5 => 10000, # Temp6 => 20000, ); foreach my $folder (sort keys %folders) { print "Folder: $folder, Files: ", $folders{$folder}, "\n"; timethese(5, { 'Way 1' => sub { opendir(my $DIR, $folder) or die "Error: couldn't open dir + '$folder': $!\n"; while(my $file = readdir $DIR) { my $filename = "$folder/$file"; if(-f $filename) { # print STDERR "$filename\n"; } } closedir($DIR); }, 'Way 2' => sub { foreach my $file (glob "$folder/*") { my $filename = $file; if(-f $filename) { # print STDERR "$filename\n"; } } }, 'Way 3' => sub { opendir(my $DIR, $folder) or die "Error: couldn't open dir + '$folder': $!\n"; my @files = map { "$folder/$_" } grep { -f "$folder/$_" } readdir($DIR); closedir($DIR); foreach my $file (@files) { my $filename = $file; # print STDERR "$filename\n"; } }, }); }
Folder: Temp1, Files: 10 Benchmark: timing 5 iterations of Way 1, Way 2, Way 3... Way 1: 0 wallclock secs ( 0.00 usr + 0.00 sys = 0.00 CPU) (warning: too few iterations for a reliable count) Way 2: 0 wallclock secs ( 0.00 usr + 0.00 sys = 0.00 CPU) (warning: too few iterations for a reliable count) Way 3: 0 wallclock secs ( 0.00 usr + 0.00 sys = 0.00 CPU) (warning: too few iterations for a reliable count) Folder: Temp2, Files: 100 Benchmark: timing 5 iterations of Way 1, Way 2, Way 3... Way 1: 0 wallclock secs ( 0.00 usr + 0.05 sys = 0.05 CPU) @ 108.70/s (n=5) (warning: too few iterations for a reliable count) Way 2: 0 wallclock secs ( 0.00 usr + 0.08 sys = 0.08 CPU) @ 63.29/s (n=5) (warning: too few iterations for a reliable count) Way 3: 0 wallclock secs ( 0.03 usr + 0.00 sys = 0.03 CPU) @ 161.29/s (n=5) (warning: too few iterations for a reliable count) Folder: Temp3, Files: 1000 Benchmark: timing 5 iterations of Way 1, Way 2, Way 3... Way 1: 1 wallclock secs ( 0.19 usr + 0.63 sys = 0.81 CPU) @ 6.15/s (n=5) Way 2: 1 wallclock secs ( 0.41 usr + 1.11 sys = 1.52 CPU) @ 3.30/s (n=5) Way 3: 1 wallclock secs ( 0.16 usr + 0.67 sys = 0.83 CPU) @ 6.04/s (n=5) Folder: Temp4, Files: 5000 Benchmark: timing 5 iterations of Way 1, Way 2, Way 3... Way 1: 9 wallclock secs ( 1.20 usr + 7.86 sys = 9.06 CPU) @ 0.55/s (n=5) Way 2: 19 wallclock secs ( 1.73 usr + 16.59 sys = 18.33 CPU) @ 0.27/s (n=5) Way 3: 10 wallclock secs ( 0.92 usr + 7.91 sys = 8.83 CPU) @ 0.57/s (n=5) Folder: Temp5, Files: 10000 Benchmark: timing 5 iterations of Way 1, Way 2, Way 3... Way 1: 43 wallclock secs ( 3.17 usr + 39.39 sys = 42.56 CPU) @ 0.12/s (n=5) Way 2: 85 wallclock secs ( 6.53 usr + 76.41 sys = 82.94 CPU) @ 0.06/s (n=5) Way 3: 42 wallclock secs ( 3.19 usr + 38.06 sys = 41.25 CPU) @ 0.12/s (n=5)
|
---|
Replies are listed 'Best First'. | |
---|---|
Re: List of directory (3 ways)
by blazar (Canon) on Jan 17, 2006 at 09:58 UTC | |
Re: List of directory (3 ways)
by radiantmatrix (Parson) on Jan 17, 2006 at 20:11 UTC | |
Re: List of directory (3 ways) (Win32 glob slow)
by tye (Sage) on Jan 17, 2006 at 21:31 UTC |
Back to
Meditations