#!/usr/bin/perl
  
use strict;
use warnings;

my $perl    = "/opt/perl/bin/perl";
my $thrperl = "/opt/perl/bin/thrperl";

my $action  = << '--';
    open my $fh => "> /dev/null" or die "open: $!";
    print $fh ".";
    close $fh;
--
    
my $prog    = << '--';
use strict;
use warnings;

my $times = shift;

my @pids;

foreach (1 .. $times) {
    defined (my $pid = fork) or die "fork: $!";
    unless ($pid) {
        ACTION;
        exit;
    }
    push @pids => $pid;
}
    
map {waitpid $_ => 0} @pids;

--


my $thrprog = << '--';
use strict;
use warnings;
use threads;
    
my $times = shift;
 
my @threads;

foreach (1 .. $times) {
    my $thread = threads -> create (sub {ACTION}) or die "threads: $!";
    push @threads => $thread;
}

map {$_ -> join} @threads;

--
    
    
my @amounts = (0, 5, 10, 25, 50, 100, 250, 500, 1000, 2500);
  
print STDERR "Empty childs\n";

(my $t_prog    = $prog)    =~ s/ACTION//;
(my $t_thrprog = $thrprog) =~ s/ACTION//;
for my $amount (@amounts) {
    my $format = sprintf "%5d: %%U user, %%S system, %%E elapsed" => $amount;
    system time => '-f', "(F) $format",    $perl, '-e',    $t_prog, $amount;
    system time => '-f', "(T) $format", $thrperl, '-e', $t_thrprog, $amount;
}

    
print STDERR "\nChilds writing\n";
        
($t_prog    = $prog)    =~ s/ACTION/$action/;
($t_thrprog = $thrprog) =~ s/ACTION/$action/;
for my $amount (@amounts) {
    my $format = sprintf "%5d: %%U user, %%S system, %%E elapsed" => $amount;
    system time => '-f', "(F) $format",    $perl, '-e',    $t_prog, $amount;
    system time => '-f', "(T) $format", $thrperl, '-e', $t_thrprog, $amount;
}

__END__
Empty childs
(F)     0: 0.01 user, 0.00 system, 0:00.01 elapsed
(T)     0: 0.04 user, 0.00 system, 0:00.03 elapsed
(F)     5: 0.01 user, 0.00 system, 0:00.01 elapsed
(T)     5: 0.09 user, 0.00 system, 0:00.09 elapsed
(F)    10: 0.01 user, 0.01 system, 0:00.02 elapsed
(T)    10: 0.16 user, 0.00 system, 0:00.15 elapsed
(F)    25: 0.01 user, 0.02 system, 0:00.03 elapsed
(T)    25: 0.32 user, 0.02 system, 0:00.34 elapsed
(F)    50: 0.03 user, 0.04 system, 0:00.06 elapsed
(T)    50: 0.60 user, 0.08 system, 0:00.70 elapsed
(F)   100: 0.04 user, 0.08 system, 0:00.11 elapsed
(T)   100: 1.25 user, 0.11 system, 0:01.42 elapsed
(F)   250: 0.04 user, 0.12 system, 0:00.50 elapsed
(T)   250: 3.41 user, 0.24 system, 0:03.87 elapsed
(F)   500: 0.02 user, 0.14 system, 0:01.16 elapsed
(T)   500: 7.37 user, 0.55 system, 0:08.42 elapsed
(F)  1000: 0.05 user, 0.19 system, 0:02.49 elapsed
A thread exited while 46 threads were running.
(T)  1000: 15.02 user, 1.36 system, 0:17.42 elapsed
(F)  2500: 0.04 user, 0.71 system, 0:06.73 elapsed
Command terminated by signal 9
(T)  2500: 37.39 user, 3.30 system, 2:10.56 elapsed
    
Childs writing
(F)     0: 0.06 user, 0.21 system, 0:01.60 elapsed
(T)     0: 0.20 user, 0.23 system, 0:01.66 elapsed
(F)     5: 0.01 user, 0.01 system, 0:00.03 elapsed
(T)     5: 0.12 user, 0.02 system, 0:00.28 elapsed
(F)    10: 0.03 user, 0.00 system, 0:00.07 elapsed
(T)    10: 0.17 user, 0.04 system, 0:00.37 elapsed
(F)    25: 0.02 user, 0.06 system, 0:00.08 elapsed
(T)    25: 0.49 user, 0.09 system, 0:01.07 elapsed
(F)    50: 0.04 user, 0.21 system, 0:00.46 elapsed
(T)    50: 0.73 user, 0.12 system, 0:01.72 elapsed
(F)   100: 0.04 user, 0.11 system, 0:00.14 elapsed
(T)   100: 1.22 user, 0.06 system, 0:01.29 elapsed
(F)   250: 0.08 user, 0.12 system, 0:00.52 elapsed
(T)   250: 2.93 user, 0.30 system, 0:04.29 elapsed
(F)   500: 0.06 user, 0.20 system, 0:01.30 elapsed
(T)   500: 6.29 user, 0.67 system, 0:07.79 elapsed
(F)  1000: 0.03 user, 0.24 system, 0:02.50 elapsed
A thread exited while 46 threads were running.
(T)  1000: 11.52 user, 1.46 system, 0:13.84 elapsed
(F)  2500: 0.06 user, 0.72 system, 0:06.78 elapsed
Command terminated by signal 9
(T)  2500: 26.72 user, 13.98 system, 3:57.20 elapsed